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Performance of a damaged brain

Performance of a damaged brain



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I have heard stories/reports that if a certain part of the brain (taking care of certain functions) is damaged other parts take over the function of the damaged part.

Intuitively this could mean 2 things:

  • We are not using the brain to its full capability.

  • The performance of the brain will take a hit due to other brain centers taking over the functionality of the damaged center.

For me the first one does not make sense since evolutionary selection makes sure we are endowed with the most efficient systems. So what is happening exactly when brain centers get damaged?


To the question "what is happening exactly when brain centres get damaged?". The answer is: When any tissue, including neural tissue, in the body gets damaged, the body will try to repair them. The process of reparation involves many distinct processes, such as the process to get rid of the damaged tissue and the process to regenerate new tissue. But compared with other tissues, such as skin, mucosa, and connective tissue in general, neural tissue has a much more limited capability to regenerate, yet it is not zero. Also, in the nervous system, neural plasticity, which is the adaptation of other neural tissue to perform the function that is impaired or lost, plays the role in the process of reparation too. The following articles may help explain this matter in more details: ref1 and ref 2, and ref3. And some animal studies of neural plasticity: ref4 and ref5.


Teen Drinking May Cause Irreversible Brain Damage

The red specks highlight where the integrity of the brain's white matter is significantly less in the teens who binge drink, compared to those who do not. Courtesy of Susan Tapert/Tim McQueeny, UCSD hide caption

The red specks highlight where the integrity of the brain's white matter is significantly less in the teens who binge drink, compared to those who do not.

Courtesy of Susan Tapert/Tim McQueeny, UCSD

For teenagers, the effects of a drunken night out may linger long after the hangover wears off.

A recent study led by neuroscientist Susan Tapert of the University of California, San Diego compared the brain scans of teens who drink heavily with the scans of teens who don't.

Tapert's team found damaged nerve tissue in the brains of the teens who drank. The researchers believe this damage negatively affects attention span in boys, and girls' ability to comprehend and interpret visual information.

"First of all, the adolescent brain is still undergoing several maturational processes that render it more vulnerable to some of the effects of substances," Tapert says.

In other words, key areas of the brain are still under construction during the adolescent years, and are more sensitive to the toxic effects of drugs and alcohol.

Damage to the brain of a teenage drinker, top view Courtesy of Susan Tapert/Tim McQueeny, UCSD hide caption

Thought, Memory Functions Affected

For the study, published last month in the journal Psychology of Addictive Behaviors, Tapert looked at 12- to 14-year-olds before they used any alcohol or drugs. Over time, some of the kids started to drink, a few rather heavily — consuming four or five drinks per occasion, two or three times a month — classic binge drinking behavior in teens.

Comparing the young people who drank heavily with those who remained non-drinkers, Tapert's team found that the binge drinkers did worse on thinking and memory tests. There was also a distinct gender difference.

"For girls who had been engaging in heavy drinking during adolescence, it looks like they're performing more poorly on tests of spatial functioning, which links to mathematics, engineering kinds of functions," Tapert says.

"For boys who engaged in binge drinking during adolescence, we see poor performance on tests of attention — so being able to focus on something that might be somewhat boring, for a sustained period of time," Tapert says. "The magnitude of the difference is 10 percent. I like to think of it as the difference between an A and a B."

Teenage Tendency To Experiment To Blame

Pediatrician and brain researcher Ron Dahl from the University of Pittsburgh notes that adolescents seem to have a higher tolerance for the negative immediate effects of binge drinking, such as feeling ill and nauseated.

"Which makes it easier to consume higher amounts and enjoy some of the positive aspects," Dahl says. "But, of course, that also creates a liability for the spiral of addiction and binge use of these substances."

He adds that there is a unique feature of the teenage brain that drives much behavior during adolescence: The teen brain is primed and ready for intense, all-consuming learning.

"Becoming passionate about a particular activity, a particular sport, passionate about literature or changing the world or a particular religion" is a normal, predictable part of being a teenager, he says.

"But those same tendencies to explore and try new things and try on new identities may also increase the likelihood of starting on negative pathways," he adds.

Damaged Brain Tissue

Tapert wanted to find out in what way binge drinking affects a teen's developing brain. So using brain imaging, she focused on the white matter, or nerve tissue, of the brain.

"White matter is very important for the relay of information between brain cells and we know that it is continuing to develop during adolescence," Tapert says.

So Tapert imaged the brains of two groups of high school students: binge drinkers and a matched group of teens with no history of binge drinking. She reports in her recent study a marked difference in the white matter of the binge drinkers.

"They appeared to have a number of little dings throughout their brains' white matter, indicating poor quality," Tapert says.

And poor quality of the brain's white matter indicates poor, inefficient communication between brain cells.

"These results were actually surprising to me because the binge drinking kids hadn't, in fact, engaged in a great deal of binge drinking. They were drinking on average once or twice a month, but when they did drink, it was to a relatively high quantity of at least four or five drinks an occasion," she says.

In another study, Tapert reported abnormal functioning in the hippocampus — a key area for memory formation — in teen binge drinkers. Reflecting their abnormal brain scans, the teen drinkers did more poorly on learning verbal material than their non-drinking counterparts.

What remains unknown, says Tapert, is if the cognitive downward slide in teenage binge drinkers is reversible.


What Causes Brain Damage?

When the brain is starved of oxygen for a prolonged period of time, brain damage may occur. Brain damage can occur as a result of a wide range of injuries, illnesses, or conditions. Because of high-risk behaviors, males between ages 15 and 24 are most vulnerable. Young children and the elderly also have a higher risk.

Causes of traumatic brain injury include:

  • Car accidents
  • Blows to the head
  • Sports injuries
  • Falls or accidents
  • Physical violence

Causes of acquired brain injury include:

  • Poisoning or exposure to toxic substances
  • Infection
  • Strangulation, choking, or drowning
  • Stroke
  • Tumors
  • Aneurysms
  • Neurological illnesses
  • Abuse of illegal drugs

Multitasking Damages Your Brain And Career, New Studies Suggest

You've likely heard that multitasking is problematic, but new studies show that it kills your performance and may even damage your brain.

Research conducted at Stanford University found that multitasking is less productive than doing a single thing at a time. The researchers also found that people who are regularly bombarded with several streams of electronic information cannot pay attention, recall information, or switch from one job to another as well as those who complete one task at a time.

A Special Skill?

But what if some people have a special gift for multitasking? The Stanford researchers compared groups of people based on their tendency to multitask and their belief that it helps their performance. They found that heavy multitaskers—those who multitask a lot and feel that it boosts their performance—were actually worse at multitasking than those who like to do a single thing at a time. The frequent multitaskers performed worse because they had more trouble organizing their thoughts and filtering out irrelevant information, and they were slower at switching from one task to another. Ouch.

Multitasking reduces your efficiency and performance because your brain can only focus on one thing at a time. When you try to do two things at once, your brain lacks the capacity to perform both tasks successfully.

Multitasking Lowers IQ

Research also shows that, in addition to slowing you down, multitasking lowers your IQ. A study at the University of London found that participants who multitasked during cognitive tasks experienced IQ score declines that were similar to what they'd expect if they had smoked marijuana or stayed up all night. IQ drops of 15 points for multitasking men lowered their scores to the average range of an 8-year-old child.

So the next time you're writing your boss an email during a meeting, remember that your cognitive capacity is being diminished to the point that you might as well let an 8-year-old write it for you.

Brain Damage From Multitasking

It was long believed that cognitive impairment from multitasking was temporary, but new research suggests otherwise. Researchers at the University of Sussex in the UK compared the amount of time people spend on multiple devices (such as texting while watching TV) to MRI scans of their brains. They found that high multitaskers had less brain density in the anterior cingulate cortex, a region responsible for empathy as well as cognitive and emotional control.

While more research is needed to determine if multitasking is physically damaging the brain (versus existing brain damage that predisposes people to multitask), it's clear that multitasking has negative effects. Neuroscientist Kep Kee Loh, the study’s lead author, explained the implications: "I feel that it is important to create an awareness that the way we are interacting with the devices might be changing the way we think and these changes might be occurring at the level of brain structure.”

Learning From Multitasking

If you’re prone to multitasking, this is not a habit you’ll want to indulge—it clearly slows you down and decreases the quality of your work. Even if it doesn’t cause brain damage, allowing yourself to multitask will fuel any existing difficulties you have with concentration, organization, and attention to detail.

Multitasking in meetings and other social settings indicates low self- and social-awareness, two emotional intelligence (EQ) skills that are critical to success at work. TalentSmart has tested more than a million people and found that 90% of top performers have high EQs. If multitasking does indeed damage the anterior cingulate cortex (a key brain region for EQ) as current research suggests, it will lower your EQ in the process.

So every time you multitask you aren't just harming your performance in the moment you may very well be damaging an area of your brain that's critical to your future success at work.


Neuroscience For Kids

Let's look at the possible origins of this "10% brain use" statement and the evidence that we use all of our brain.

Where Did the 10% Myth Begin?

The 10% statement may have been started with a misquote of Albert Einstein or the misinterpretation of the work of Pierre Flourens in the 1800s. It may have been William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, p. 12). Perhaps it was the work of Karl Lashley in the 1920s and 1930s that started it. Lashley removed large areas of the cerebral cortex in rats and found that these animals could still relearn specific tasks. We now know that destruction of even small areas of the human brain can have devastating effects on behavior. That is one reason why neurosurgeons must carefully map the brain before removing brain tissue during operations for epilepsy or brain tumors: they want to make sure that essential areas of the brain are not damaged.

Why Does the Myth Continue?

Somehow, somewhere, someone started this myth and the popular media keep on repeating this false statement (see the figures). Soon, everyone believes the statement regardless of the evidence. I have not been able to track down the exact source of this myth, and I have never seen any scientific data to support it. According to the believers of this myth, if we used more of our brain, then we could perform super memory feats and have other fantastic mental abilities - maybe we could even move objects with a single thought. Again, I do not know of any data that would support any of this.

What Does it Mean to Use Only 10% of Your Brain?

What data were used to come up with the number - 10%? Does this mean that you would be just fine if 90% of your brain was removed? If the average human brain weighs 1,400 grams (about 3 lb) and 90% of it was removed, that would leave 140 grams (about 0.3 lb) of brain tissue. That's about the size of a sheep's brain. It is well known that damage to a relatively small area of the brain, such as that caused by a stroke, may cause devastating disabilities. Certain neurological disorders, such as Parkinson's Disease, also affect only specific areas of the brain. The damage caused by these conditions is far less than damage to 90% of the brain.

The Evidence (or lack of it)

Perhaps when people use the 10% brain statement, they mean that only one out of every ten nerve cells is essential or used at any one time? How would such a measurement be made? Even if neurons are not firing action potentials, they may still be receiving signals from other neurons.

Furthermore, from an evolutionary point of view, it is unlikely that larger brains would have developed if there was not an advantage. Certainly there are several pathways that serve similar functions. For example, there are several central pathways that are used for vision. This concept is called "redundancy" and is found throughout the nervous system. Multiple pathways for the same function may be a type of safety mechanism should one of the pathways fail. Still, functional brain imaging studies show that all parts of the brain function. Even during sleep, the brain is active. The brain is still being "used," it is just in a different active state.

Finally, the saying "Use it or Lose It" seems to apply to the nervous system. During development many new synapses are formed. In fact, some synapses are eliminated later on in development. This period of synaptic development and elimination goes on to "fine tune" the wiring of the nervous system. Many studies have shown that if the input to a particular neural system is eliminated, then neurons in this system will not function properly. This has been shown quite dramatically in the visual system: complete loss of vision will occur if visual information is prevented from stimulating the eyes (and brain) early in development. It seems reasonable to suggest that if 90% of the brain was not used, then many neural pathways would degenerate. However, this does not seem to be the case. On the other hand, the brains of young children are quite adaptable. The function of a damaged brain area in a young brain can be taken over by remaining brain tissue. There are incredible examples of such recovery in young children who have had large portions of their brains removed to control seizures. Such miraculous recovery after extensive brain surgery is very unusual in adults.

So next time you hear someone say that they only use 10% of their brain, you can set them straight. Tell them:

"We use 100% of our brains."

Several people have mentioned that the movie Lucy (2014) promotes the 10% of the brain myth. If you find any news articles or advertisements using the 10% myth, please send them to me: Dr. Eric H. Chudler.


Cognition, Brain, & Behavior

Research in the Cognition, Brain, and Behavior (CBB) group includes studies of sensation and perception, learning and memory, attention, mental imagery, conceptual representation, aging, language, emotion, motor control, social cognition, moral decision making, and neurological disorders. The subjects for these studies range from normal human adults and infants to brain-damaged patients, and various non-human primate and avian species. Methodologies include computer-based behavioral tests and web-based surveys to assess functional patterns in behavior, as well as functional neuroimaging techniques (such as magnetic resonance imaging, electroencephalography, magnetoencephalography and transcranial magnetic stimulation) to study the neural bases of various components of cognition and behavior.


What Occurs in the Brain When You Multitask

Humans are capable of doing two things at a time, especially when one of those activities is so ingrained that it can be done on autopilot.

Most of us can carry on a conversation while walking or drink coffee while driving — no problem.

But what we can’t do is learn or concentrate on two things at once.

" Distracted walking causes pedestrians to get hit by cars, fall off bridges, and stumble onto subway tracks.

When the brain is presented with two tasks at once, it quickly toggles back and forth between them.

But when your brain receives more information than it can process, an area of your brain called the posterior lateral prefrontal cortex (pLPFC) takes over. (3)

It acts as a hub for routing new stimuli.

Your pLPFC will line these stimuli up in a queue, rather than trying to handle them simultaneously.

But if new stimuli come too rapidly, the pLPFC simply queues up the first two pieces of information and ignores the rest.

A quality brain supplement can make a big difference.

Dr. Pat | Be Brain Fit


Contents

Symptoms of brain injuries vary based on the severity of the injury or how much of the brain is affected. The three categories used for classifying the severity of brain injuries are mild, moderate or severe. [2]

Mild brain injuries Edit

Symptoms of a mild brain injury include headaches, confusions, tinnitus, fatigue, changes in sleep patterns, mood or behavior. Other symptoms include trouble with memory, concentration, attention or thinking. [3] Mental fatigue is a common debilitating experience and may not be linked by the patient to the original (minor) incident. Narcolepsy and sleep disorders are common misdiagnoses. [4]

Moderate/severe brain injuries Edit

Cognitive symptoms include confusion, aggressiveness, abnormal behavior, slurred speech, and coma or other disorders of consciousness. Physical symptoms include headaches that worsen or do not go away, vomiting or nausea, convulsions, abnormal dilation of the eyes, inability to awaken from sleep, weakness in extremities and loss of coordination. [3]

Symptoms in children Edit

Symptoms observed in children include changes in eating habits, persistent irritability or sadness, changes in attention, disrupted sleeping habits, or loss of interest in toys. [3]

Location of brain damage predicts symptoms Edit

Symptoms of brain injuries can also be influenced by the location of the injury and as a result impairments are specific to the part of the brain affected. Lesion size is correlated with severity, recovery, and comprehension. [5] Brain injuries often create impairment or disability that can vary greatly in severity.

In cases of severe brain injuries, the likelihood of areas with permanent disability is great, including neurocognitive deficits, delusions (often, to be specific, monothematic delusions), speech or movement problems, and intellectual disability. There may also be personality changes. The most severe cases result in coma or even persistent vegetative state. Even a mild incident can have long-term effects or cause symptoms to appear years later. [6]

Studies show there is a correlation between brain lesion and language, speech, and category-specific disorders. Wernicke's aphasia is associated with anomia, unknowingly making up words (neologisms), and problems with comprehension. The symptoms of Wernicke’s aphasia are caused by damage to the posterior section of the superior temporal gyrus. [7] [8]

Damage to the Broca’s area typically produces symptoms like omitting functional words (agrammatism), sound production changes, dyslexia, dysgraphia, and problems with comprehension and production. Broca’s aphasia is indicative of damage to the posterior inferior frontal gyrus of the brain. [9]

An impairment following damage to a region of the brain does not necessarily imply that the damaged area is wholly responsible for the cognitive process which is impaired, however. For example, in pure alexia, the ability to read is destroyed by a lesion damaging both the left visual field and the connection between the right visual field and the language areas (Broca's area and Wernicke's area). However, this does not mean one suffering from pure alexia is incapable of comprehending speech—merely that there is no connection between their working visual cortex and language areas—as is demonstrated by the fact that pure alexics can still write, speak, and even transcribe letters without understanding their meaning. [10]

Lesions to the fusiform gyrus often result in prosopagnosia, the inability to distinguish faces and other complex objects from each other. [11] Lesions in the amygdala would eliminate the enhanced activation seen in occipital and fusiform visual areas in response to fear with the area intact. Amygdala lesions change the functional pattern of activation to emotional stimuli in regions that are distant from the amygdala. [12]

Other lesions to the visual cortex have different effects depending on the location of the damage. Lesions to V1, for example, can cause blindsight in different areas of the brain depending on the size of the lesion and location relative to the calcarine fissure. [13] Lesions to V4 can cause color-blindness, [14] and bilateral lesions to MT/V5 can cause the loss of the ability to perceive motion. Lesions to the parietal lobes may result in agnosia, an inability to recognize complex objects, smells, or shapes, or amorphosynthesis, a loss of perception on the opposite side of the body. [15]

Non-localizing features Edit

Brain injuries have far-reaching and varied consequences due to the nature of the brain as the main source of bodily control. Brain-injured people commonly experience issues with memory. [16] This can be issues with either long or short-term memories depending on the location and severity of the injury. Sometimes memory can be improved through rehabilitation, although it can be permanent. Behavioral and personality changes are also commonly observed due to changes of the brain structure in areas controlling hormones or major emotions. Headaches and pain can also occur as a result of a brain injury either directly from the damage or due to neurological conditions stemming from the injury. Due to the changes in the brain as well as the issues associated with the change in physical and mental capacity, depression and low self-esteem are common side effects that can be treated with psychological help. Antidepressants must be used with caution in brain injury people due to the potential for undesired effects because of the already altered brain chemistry.

Long term psychological and physiological effects Edit

There are multiple responses of the body to brain injury, occurring at different times after the initial occurrence of damage, as the functions of the neurons, nerve tracts, or sections of the brain can be affected by damage. The immediate response can take many forms. Initially, there may be symptoms such as swelling, pain, bruising, or loss of consciousness. [17] Post-traumatic amnesia is also common with brain damage, as is temporary aphasia, or impairment of language. [18]

As time progresses, and the severity of injury becomes clear, there are further responses that may become apparent. Due to loss of blood flow or damaged tissue, sustained during the injury, amnesia and aphasia may become permanent, and apraxia has been documented in patients. Amnesia is a condition in which a person is unable to remember things. [19] Aphasia is the loss or impairment of word comprehension or use. Apraxia is a motor disorder caused by damage to the brain, and may be more common in those who have been left brain damaged, with loss of mechanical knowledge critical. [20] Headaches, occasional dizziness, and fatigue—all temporary symptoms of brain trauma—may become permanent, or may not disappear for a long time.

There are documented cases of lasting psychological effects as well, such as emotional changes often caused by damage to the various parts of the brain that control human emotions and behavior. [21] Individuals who have experienced emotional changes related to brain damage may have emotions that come very quickly and are very intense, but have very little lasting effect. [21] Emotional changes may not be triggered by a specific event, and can be a cause of stress to the injured party and their family and friends. [22] Often, counseling is suggested for those who experience this effect after their injury, and may be available as an individual or group session.

It is important to note that the long term psychological and physiological effects will vary by person and injury. For example, perinatal brain damage has been implicated in cases of neurodevelopmental impairments and psychiatric illnesses. If any concerning symptoms, signs, or changes to behaviors are occurring, a healthcare provider should be consulted.

Unlike some of the more obvious responses to brain damage, the body also has invisible physical responses which can be difficult to notice. These will generally be identified by a healthcare provider, especially as they are normal physical responses to brain damage. Cytokines are known to be induced in response to brain injury. [23] These have diverse actions that can cause, exacerbate, mediate and/or inhibit cellular injury and repair. TGFβ seems to exert primarily neuroprotective actions, whereas TNFα might contribute to neuronal injury and exert protective effects. IL-1 mediates ischaemic, excitotoxic, and traumatic brain injury, probably through multiple actions on glia, neurons, and the vasculature. Cytokines may be useful in order to discover novel therapeutic strategies. At the current time, they are already in clinical trials. [24]

Brain injuries can result from a number of conditions including: [25]

Chemotherapy Edit

Chemotherapy can cause brain damage to the neural stem cells and oligodendrocyte cells that produce myelin. Radiation and chemotherapy can lead to brain tissue damage by disrupting or stopping blood flow to the affected areas of the brain. This damage can cause long term effects such as but not limited to memory loss, confusion, and loss of cognitive function. The brain damage caused by radiation depends on where the brain tumor is located, the amount of radiation used, and the duration of the treatment. Radiosurgery can also lead to tissue damage that results in about 1 in 20 patients requiring a second operation to remove the damaged tissue. [29] [30]

Wernicke-Korsakoff syndrome Edit

Wernicke-Korsakoff syndrome can cause brain damage and results from a Vitamin B deficiency. This syndrome presents with two conditions, Wernicke’s encephalopathy and Korsakoff psychosis. Typically Wernicke’s encephalopathy precedes symptoms of Korsakoff psychosis. Wernicke’s encephalopathy causes bleeding in the thalamus or hypothalamus, which controls the nervous and endocrine system. Due to the bleeding, brain damage occurs causing problems with vision, coordination, and balance. Korsakoff psychosis typically follows after the symptoms of Wernicke’s decrease and result from chronic brain damage. [31] Korsakoff psychosis affect memory. Wernicke-Korsakoff syndrome is typically caused by chronic heavy alcohol use or by conditions that affect nutritional absorption, including colon cancer, eating disorders and gastric bypass. [32]

Iatrogenic Edit

Brain lesions are sometimes intentionally inflicted during neurosurgery, such as the carefully placed brain lesion used to treat epilepsy and other brain disorders. These lesions are induced by excision or by electric shocks (electrolytic lesions) to the exposed brain or commonly by infusion of excitotoxins to specific areas. [33]

Diffuse axonal Edit

Diffuse axonal injury is caused by shearing forces on the brain leading to lesions in the white matter tracts of the brain. [34] These shearing forces are seen in cases where the brain had a sharp rotational acceleration, and is caused by the difference in density between white matter and grey matter. [35]

Glasgow Coma Scale (GCS) is the most widely used scoring system used to assess the level of severity of a brain injury. This method is based on the objective observations of specific traits to determine the severity of a brain injury. It is based on three traits: eye opening, verbal response, and motor response, gauged as described below. [36] Based on the Glasgow Coma Scale severity is classified as follows, severe brain injuries score 3–8, moderate brain injuries score 9–12 and mild score 13–15. [36]

There are several imaging techniques that can aid in diagnosing and assessing the extent of brain damage, such as computed tomography (CT) scan, magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and single-photon emission tomography (SPECT). CT scans and MRI are the two techniques widely used and are most effective. CT scans can show brain bleeds, fractures of the skull, fluid build up in the brain that will lead to increased cranial pressure. MRI is able to better to detect smaller injuries, detect damage within the brain, diffuse axonal injury, injuries to the brainstem, posterior fossa, and subtemporal and subfrontal regions. However, patients with pacemakers, metallic implants, or other metal within their bodies are unable to have an MRI done. Typically the other imaging techniques are not used in a clinical setting because of the cost, lack of availability. [37]

Acute Edit

The treatment for emergency traumatic brain injuries focuses on assuring the person has enough oxygen from the brain blood supply, and on maintaining normal blood pressure to avoid further injuries of the head or neck. The person may need surgery to remove clotted blood or repair skull fractures, for which cutting a hole in the skull may be necessary. Medicines used for traumatic injuries are diuretics, anti-seizure or coma-inducing drugs. Diuretics reduce the fluid in tissues lowering the pressure on the brain. In the first week after a traumatic brain injury, a person may have a risk of seizures, which anti-seizure drugs help prevent. Coma-inducing drugs may be used during surgery to reduce impairments and restore blood flow.

In the case of brain damage from traumatic brain injury, dexamethasone and/or Mannitol may be used. [38]

Chronic Edit

Various professions may be involved in the medical care and rehabilitation of someone suffering impairment after a brain injury. Neurologists, neurosurgeons, and physiatrists are physicians specialising in treating brain injury. Neuropsychologists (especially clinical neuropsychologists) are psychologists specialising in understanding the effects of brain injury and may be involved in assessing the severity or creating rehabilitation strategies. Occupational therapists may be involved in running rehabilitation programs to help restore lost function or help re-learn essential skills. Registered nurses, such as those working in hospital intensive care units, are able to maintain the health of the severely brain-injured with constant administration of medication and neurological monitoring, including the use of the Glasgow Coma Scale used by other health professionals to quantify extent of orientation. [39]

Physiotherapists also play a significant role in rehabilitation after a brain injury. In the case of a traumatic brain injury (TBIs), physiotherapy treatment during the post-acute phase may include: sensory stimulation, serial casting and splinting, fitness and aerobic training, and functional training. [40] Sensory stimulation refers to regaining sensory perception through the use of modalities. There is no evidence to support the efficacy of this intervention. [41] Serial casting and splinting are often used to reduce soft tissue contractures and muscle tone. Evidence based research reveals that serial casting can be used to increase passive range of motion (PROM) and decrease spasticity. [41] Studies also report that fitness and aerobic training will increase cardiovascular fitness however the benefits will not be transferred to the functional level. [42] Functional training may also be used to treat patients with TBIs. To date, no studies supports the efficacy of sit to stand training, arm ability training and body weight support systems (BWS). [43] [44] Overall, studies suggest that patients with TBIs who participate in more intense rehabilitation programs will see greater benefits in functional skills. [42] More research is required to better understand the efficacy of the treatments mentioned above. [45]

Prognosis, or the likely progress of a disorder, depends on the nature, location, and cause of the brain damage (see Traumatic brain injury, Focal and diffuse brain injury, Primary and secondary brain injury).

In general, neuroregeneration can occur in the peripheral nervous system but is much rarer and more difficult to assist in the central nervous system (brain or spinal cord). However, in neural development in humans, areas of the brain can learn to compensate for other damaged areas, and may increase in size and complexity and even change function, just as someone who loses a sense may gain increased acuity in another sense – a process termed neuroplasticity. [46]

There are many misconceptions that revolve around brain injuries and brain damage. One misconception is that if someone has brain damage then they cannot fully recover. Recovery depends a variety of factors such as severity and location. Testing is done to note severity and location. Not everyone fully heals from brain damage, but it is possible to have a full recovery. Brain injuries are very hard to predict in outcome. Many tests and specialists are needed to determine the likelihood of the prognosis. People with minor brain damage can have debilitating side effects not just severe brain damage has debilitating effects. [47] The side- effects of a brain injury depend on location and the body’s response to injury. [47] Even a mild concussion can have long term effects that may not resolve. [48] Another misconception is that children heal better from brain damage. Children are at greater risk for injury due to lack of maturity. It makes future development hard to predict. [48] [ dead link ] This is because different cortical areas mature at different stages, with some major cell populations and their corresponding cognitive faculties remaining unrefined until early adulthood. In the case of a child with frontal brain injury, for example, the impact of the damage may be undetectable until that child fails to develop normal executive functions in his or her late teens and early twenties. [49]

The foundation for understanding human behavior and brain injury can be attributed to the case of Phineas Gage and the famous case studies by Paul Broca. The first case study on Phineas Gage’s head injury is one of the most astonishing brain injuries in history. In 1848, Phineas Gage was paving way for a new railroad line when he encountered an accidental explosion of a tamping iron straight through his frontal lobe. Gage observed to be intellectually unaffected but exemplified post injury behavioral deficits. These deficits include: becoming sporadic, disrespectful, extremely profane, and gave no regard for other workers. Gage started having seizures in February, dying only four months later on May 21, 1860. [50]

Ten years later, Paul Broca examined two patients exhibiting impaired speech due to frontal lobe injuries. Broca’s first patient lacked productive speech. He saw this as an opportunity to address language localization. It wasn't until Leborgne, formally known as "tan", died when Broca confirmed the frontal lobe lesion from an autopsy. The second patient had similar speech impairments, supporting his findings on language localization. The results of both cases became a vital verification of the relationship between speech and the left cerebral hemisphere. The affected areas are known today as Broca’s area and Broca’s Aphasia. [51]

A few years later, a German neuroscientist, Carl Wernicke, consulted on a stroke patient. The patient experienced neither speech nor hearing impairments, but suffered from a few brain deficits. These deficits included: lacking the ability to comprehend what was spoken to him and the words written down. After his death, Wernicke examined his autopsy that found a lesion located in the left temporal region. This area became known as Wernicke's area. Wernicke later hypothesized the relationship between Wernicke's area and Broca's area, which was proven fact. [52]


This Is How Your Brain Reacts To Losing A Loved One

Grief can be healthy&mdashbut it changes your brain, too. These steps ensure a strong recovery.

Recently, my 58-year-old younger brother, a fit-and-sturdy Marine combat veteran, was diagnosed with lung cancer and died. Two weeks later, after an almost entirely disease-free life, I had to undergo eye surgery for cataracts. Since then, I've been thinking a lot about the inevitable setbacks we all encounter and how our brains deal with them. (Boost your memory and age-proof your mind with these natural solutions.)

Researchers completed an intriguing study that illustrates just how profound and widespread the effect of negative personal events can be and how your brain reacts to grief. Three finance professors from major business schools tracked the performance of 75,000 Danish companies in the 2 years before and after the CEO had experienced a family death. Financial performance declined 20% after the loss of a child, 15% after the death of a spouse, and almost 10% after the demise of any other family member.

Indeed, when brain imaging studies are done on people who are grieving, increased activity is seen along a broad network of neurons. These link areas associated not only with mood but also with memory, perception, conceptualization, and even the regulation of the heart, the digestive system, and other organs. This shows the pervasive impact loss or even disappointment can have. And the more we dwell on negative thoughts, the more developed these neural pathways become. The result can be chronic preoccupation, sadness, or even depression.

So how can we learn to deal with loss, disappointment, and everyday setbacks more constructively? Keep in mind these coping strategies for grief, which are working for me:

Be on the alert for "intruders." As soon as you recognize an intrusive negative thought, visualize a stop sign. Even go so far as to say "Stop!" if it helps. Or try wearing a rubber band around your wrist and snap yourself out of it.

Schedule your sad memories. Just as you don't immediately indulge every pang of hunger, put off sad remembrances for a time when you don't need to be productive or engaged (say, during your lunch hour). Never examine such thoughts before bed, however. This is an invitation for negativity and blame to gather strength. Prior to sleep, electrical activity diminishes in brain regions associated with analytical reasoning, and we become less objective.

Don't tolerate self-accusing or superstitious thoughts. Examples of these would be If only I had been, or Bad things happen in threes. Such thinking has no logical basis or benefit.

View setbacks as opportunities. Effectively dealing with difficulties that don't incapacitate you will make you stronger.

Finally, keep in mind that during these emotionally vulnerable times, we all create illusions. We focus almost exclusively on how wonderful those who've disappeared from our lives made us feel, and we convince ourselves that no one could ever affect us like that again. I miss my brother, no doubt about it. I know that I can't avoid illness and death in my life, but I can choose how to deal with them. I'm lucky to have known my brother for 58 years, but I'm not going to dwell on the thought that our time together could have been longer.


Introduction

Beginning with the discovery of the left-hemispheric dominance of language (Broca, 1861 Dax, 1865) it has now been shown that practically all higher functions including memory, learning, perception, spatial cognition, attention, complex motor skills, and emotion processing show some degree of hemispheric specialization (Hellige, 1993 Davidson and Hugdahl, 1995). At first, lateralization was believed to be a unique human feature (Crow, 2002) but in the meantime it has been documented in a wide range of species (Vallortigara and Rogers, 2005). Brain asymmetries in humans, however, are typically more pronounced than in animals and it has been argued that they gave rise to our superior verbal and intellectual skills (Corballis, 1991, 2009). Previous research has shown that the degree of lateralization in humans is subject to inter- and intraindividual differences. For example, some individuals show strong left-hemispheric language lateralization, others strong-right-hemispheric language lateralization, and still others possess a more bilateral language representation (Knecht et al., 2000). Even within individuals lateralization changes as a function of, for example, sex hormones (Hausmann and Güntürkün, 2000 Bayer and Hausmann, 2009 Hjelmervik et al., 2012) or emotional states (Papousek et al., 2011, 2012). However, not much is known about how degree of lateralization and performance in selected functions are related, which we refer to as the 𠇊symmetry-performance relationship”, and the few studies available provide incoherent results. For example, Everts et al. (2009) found that a stronger language lateralization, determined with functional magnetic resonance imaging (fMRI), was correlated with a higher verbal IQ. Chiarello et al. (2009) used visual half-field paradigms to assess language lateralization and also found a positive correlation between the degree of lateralization in these tasks and reading skills. On the other hand, there are also studies showing that performance deteriorates with increasing asymmetry. For example, less lateralized participants outperform more lateralized individuals in a face discrimination task (Ladavas and Umilta, 1983) and when two cognitive tasks (i.e., face discrimination and lexical decision) are performed in parallel (Hirnstein et al., 2008). Moreover, individuals with higher degrees of language lateralization as determined with fMRI (van Ettinger-Veenstra et al., 2010) or magnetic resonance diffusion tensor imaging (Catani et al., 2007) performed better on tests assessing verbal abilities (van Ettinger-Veenstra et al., 2010) or verbal memory (Catani et al., 2007) than individuals with lower degrees of lateralization. The inconsistent findings are neatly illustrated by Razafimandimby et al. (2011) who found that verb generation correlated both positively with precuneus asymmetry and negatively with cerebellum asymmetry (as determined with fMRI).

Boles et al. (2008) carried out the most extensive investigations regarding the asymmetry-performance relationship. They had data from several visual half-field and dichotic listening (DL) tasks that assessed various verbal and non-verbal cognitive functions. To obtain the asymmetry-performance relationship, they correlated the degree of lateralization derived from these tasks with the overall accuracy (or reaction times) – also derived from these tasks. The results are in line with the inconsistent findings described above. Boles et al. (2008) found positive asymmetry-performance relationships in four tasks assessing auditory linguistic and spatial positional functions. Negative relationships emerged in seven tasks assessing planar categorical, spatial emergent, spatial quantitative, and visual lexical functions. The authors concluded that the asymmetry-performance relationship is function-dependent and suggested a neurodevelopmental model according to which functions that lateralize very early (until 5 years of age) and very late in the ontogenetic development (after 11 years of age) yield positive asymmetry-performance correlations. Functions that lateralize at intermediate stages on the other hand show negative correlations.

The neurodevelopmental theory of Boles et al. (2008) may account for some of the strikingly inconsistent results. However, there are a number of methodological pitfalls which might contribute to the inconsistencies above. One of these issues is the “task purity problem” (Boles and Barth, 2011). If lateralization is assessed with one task and then correlated with performance in another task, correlations between lateralization and performance might be confounded by a third variable and do not reveal the pure asymmetry-performance relationship (Boles and Barth, 2011 but see also the reply of Chiarello et al., 2011). If one derives the performance and lateralization from the same task, however, one is faced with the problem of interdependency between left (L) and right (R) scores. Both the overall accuracy (i.e., sum or mean of L and R) and the degree of lateralization [i.e., (R - L)/(R + L) or (R - L)/(200 - R - L)] are derived from the same L and R scores. Given that L and R scores are typically correlated with each other, there is a risk that the asymmetry-performance relationship is simply the result of, or at least confounded with, this correlation between L and R scores.

The vast majority of studies that investigated the asymmetry-performance relationship in one task do not address the interdependency issue. To solve this problem, Leask and Crow (1997, 2006) developed a method that compares the asymmetry-performance relationship based on R and L scores with reference models in which R and L scores have been modeled such that they do not correlate. Another advantage of this procedure is that it is data-driven and can detect any form of asymmetry-performance relationships. Most studies simply assume linear asymmetry-performance relationships. By applying the procedure suggested by Leask and Crow (1997, 2006) to data from two visual half-field paradigms (i.e., word recognition, face discrimination), Hirnstein et al. (2010) found an inverted u-shaped association between asymmetry and performance. That is, individuals with a symmetric brain organization performed best and performance deteriorated with increasing left or right lateralization. However, the calculation of the degree of asymmetry [(R - L)/(R + L)] in this study has been criticized by Boles and Barth (2011).

It should be noted that almost all of the aforementioned studies that investigated the asymmetry-performance relationship tested right-handed adults (Catani et al., 2007 Boles et al., 2008 Hirnstein et al., 2010 van Ettinger-Veenstra et al., 2010) leaving it unclear whether the findings also apply to other populations such as left-handers, children and adolescents, which are assumed to be less lateralized in verbal and non-verbal functions (e.g., Rasmussen and Milner, 1977 Everts et al., 2009). In general, interindividual differences in the asymmetry-performance relationship are hardly investigated even though there are hints that they exist. Chiarello et al. (2009) reported that the positive correlation between language lateralization and reading skills was stronger in individuals with a consistent hand preference as compared to participants with an inconsistent hand preference. Hirnstein et al. (2010) found that males with a strong left-hemispheric lateralization in a face discrimination task performed rather poorly, while females with a strong left-hemispheric lateralization performed rather well. Thus the asymmetry-performance relationship might also be sex-specific. Finally, little is known about age effects. Only Barth et al. (2012) studied whether the positive asymmetry-performance relationship that they found in a verbal DL task in adults (Boles et al., 2008) also emerged in children. Moreover, they examined whether, in accordance with their neurodevelopmental model, adults but not children showed a negative relationship in emotional face discrimination. While the results mostly confirmed their hypotheses, some of the correlations did not reach statistical significance. According to the authors this was due to the relatively small sample size (25 children, 32 adults) emphasizing that sufficient statistical power is needed to reveal the asymmetry-performance relationship.

With some exceptions (Boles et al., 2008 van Ettinger-Veenstra et al., 2010 Barth et al., 2012) most of the studies on the asymmetry-performance relationship used visual tasks and visual asymmetry (Ladavas and Umilta, 1983 Boles et al., 2008 Hirnstein et al., 2008, 2010 Chiarello et al., 2009). Since the relationship between brain asymmetry and task performance should be generic and not dependent on sensory modality, similar relationships should be possible to obtain in the auditory modality, using, e.g., a DL task, which is perhaps the most frequently used task for assessing hemispheric asymmetry (see Hugdahl, 2011 Kimura, 2011 for recent overviews of the use of DL in asymmetry research). Over the years, Kenneth Hugdahl and our research group at the University of Bergen have built up a database with DL data, which now comprises 1839 individuals (see Hugdahl, 2003 for a description of the database). The sample covers a wide age range (5� years), has a balanced sex ratio (927 females, 912 males) and a proportion of non-right-handers of 8.9% which is close to the 10% typically observed in the general population (McManus, 2002). The large number of participants allows a comprehensive examination of the asymmetry-performance relationship and further provides an ideal opportunity to also take into account sex, handedness, and age effects. Two previous studies found that overall accuracy in verbal DL increased as asymmetries became stronger (Boles et al., 2008 Barth et al., 2012), however, leaving the interdependency issue of L and R scores unsolved. Using the approach by Boles et al. (2008), the present study examined first whether we could replicate the positive asymmetry-performance relationship found by this group. In a second step, we applied the approach by Leask and Crow (1997, 2006) which controls for the interdependency issues. By applying this approach, we also took sex, handedness, and age into account. In line with Boles et al. (2008), we hypothesized that individuals with stronger ear advantages (corresponding to a stronger degree of language lateralization) would generally report more stimuli correctly. Consequently, non-right-handers, women, and children, who are assumed to be less lateralized for language, should generally report less syllables correctly. However, this requires asymmetry-performance relationships to be consistent across all subsamples.


Neuroscience For Kids

Let's look at the possible origins of this "10% brain use" statement and the evidence that we use all of our brain.

Where Did the 10% Myth Begin?

The 10% statement may have been started with a misquote of Albert Einstein or the misinterpretation of the work of Pierre Flourens in the 1800s. It may have been William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, p. 12). Perhaps it was the work of Karl Lashley in the 1920s and 1930s that started it. Lashley removed large areas of the cerebral cortex in rats and found that these animals could still relearn specific tasks. We now know that destruction of even small areas of the human brain can have devastating effects on behavior. That is one reason why neurosurgeons must carefully map the brain before removing brain tissue during operations for epilepsy or brain tumors: they want to make sure that essential areas of the brain are not damaged.

Why Does the Myth Continue?

Somehow, somewhere, someone started this myth and the popular media keep on repeating this false statement (see the figures). Soon, everyone believes the statement regardless of the evidence. I have not been able to track down the exact source of this myth, and I have never seen any scientific data to support it. According to the believers of this myth, if we used more of our brain, then we could perform super memory feats and have other fantastic mental abilities - maybe we could even move objects with a single thought. Again, I do not know of any data that would support any of this.

What Does it Mean to Use Only 10% of Your Brain?

What data were used to come up with the number - 10%? Does this mean that you would be just fine if 90% of your brain was removed? If the average human brain weighs 1,400 grams (about 3 lb) and 90% of it was removed, that would leave 140 grams (about 0.3 lb) of brain tissue. That's about the size of a sheep's brain. It is well known that damage to a relatively small area of the brain, such as that caused by a stroke, may cause devastating disabilities. Certain neurological disorders, such as Parkinson's Disease, also affect only specific areas of the brain. The damage caused by these conditions is far less than damage to 90% of the brain.

The Evidence (or lack of it)

Perhaps when people use the 10% brain statement, they mean that only one out of every ten nerve cells is essential or used at any one time? How would such a measurement be made? Even if neurons are not firing action potentials, they may still be receiving signals from other neurons.

Furthermore, from an evolutionary point of view, it is unlikely that larger brains would have developed if there was not an advantage. Certainly there are several pathways that serve similar functions. For example, there are several central pathways that are used for vision. This concept is called "redundancy" and is found throughout the nervous system. Multiple pathways for the same function may be a type of safety mechanism should one of the pathways fail. Still, functional brain imaging studies show that all parts of the brain function. Even during sleep, the brain is active. The brain is still being "used," it is just in a different active state.

Finally, the saying "Use it or Lose It" seems to apply to the nervous system. During development many new synapses are formed. In fact, some synapses are eliminated later on in development. This period of synaptic development and elimination goes on to "fine tune" the wiring of the nervous system. Many studies have shown that if the input to a particular neural system is eliminated, then neurons in this system will not function properly. This has been shown quite dramatically in the visual system: complete loss of vision will occur if visual information is prevented from stimulating the eyes (and brain) early in development. It seems reasonable to suggest that if 90% of the brain was not used, then many neural pathways would degenerate. However, this does not seem to be the case. On the other hand, the brains of young children are quite adaptable. The function of a damaged brain area in a young brain can be taken over by remaining brain tissue. There are incredible examples of such recovery in young children who have had large portions of their brains removed to control seizures. Such miraculous recovery after extensive brain surgery is very unusual in adults.

So next time you hear someone say that they only use 10% of their brain, you can set them straight. Tell them:

"We use 100% of our brains."

Several people have mentioned that the movie Lucy (2014) promotes the 10% of the brain myth. If you find any news articles or advertisements using the 10% myth, please send them to me: Dr. Eric H. Chudler.


Cognition, Brain, & Behavior

Research in the Cognition, Brain, and Behavior (CBB) group includes studies of sensation and perception, learning and memory, attention, mental imagery, conceptual representation, aging, language, emotion, motor control, social cognition, moral decision making, and neurological disorders. The subjects for these studies range from normal human adults and infants to brain-damaged patients, and various non-human primate and avian species. Methodologies include computer-based behavioral tests and web-based surveys to assess functional patterns in behavior, as well as functional neuroimaging techniques (such as magnetic resonance imaging, electroencephalography, magnetoencephalography and transcranial magnetic stimulation) to study the neural bases of various components of cognition and behavior.


Contents

Symptoms of brain injuries vary based on the severity of the injury or how much of the brain is affected. The three categories used for classifying the severity of brain injuries are mild, moderate or severe. [2]

Mild brain injuries Edit

Symptoms of a mild brain injury include headaches, confusions, tinnitus, fatigue, changes in sleep patterns, mood or behavior. Other symptoms include trouble with memory, concentration, attention or thinking. [3] Mental fatigue is a common debilitating experience and may not be linked by the patient to the original (minor) incident. Narcolepsy and sleep disorders are common misdiagnoses. [4]

Moderate/severe brain injuries Edit

Cognitive symptoms include confusion, aggressiveness, abnormal behavior, slurred speech, and coma or other disorders of consciousness. Physical symptoms include headaches that worsen or do not go away, vomiting or nausea, convulsions, abnormal dilation of the eyes, inability to awaken from sleep, weakness in extremities and loss of coordination. [3]

Symptoms in children Edit

Symptoms observed in children include changes in eating habits, persistent irritability or sadness, changes in attention, disrupted sleeping habits, or loss of interest in toys. [3]

Location of brain damage predicts symptoms Edit

Symptoms of brain injuries can also be influenced by the location of the injury and as a result impairments are specific to the part of the brain affected. Lesion size is correlated with severity, recovery, and comprehension. [5] Brain injuries often create impairment or disability that can vary greatly in severity.

In cases of severe brain injuries, the likelihood of areas with permanent disability is great, including neurocognitive deficits, delusions (often, to be specific, monothematic delusions), speech or movement problems, and intellectual disability. There may also be personality changes. The most severe cases result in coma or even persistent vegetative state. Even a mild incident can have long-term effects or cause symptoms to appear years later. [6]

Studies show there is a correlation between brain lesion and language, speech, and category-specific disorders. Wernicke's aphasia is associated with anomia, unknowingly making up words (neologisms), and problems with comprehension. The symptoms of Wernicke’s aphasia are caused by damage to the posterior section of the superior temporal gyrus. [7] [8]

Damage to the Broca’s area typically produces symptoms like omitting functional words (agrammatism), sound production changes, dyslexia, dysgraphia, and problems with comprehension and production. Broca’s aphasia is indicative of damage to the posterior inferior frontal gyrus of the brain. [9]

An impairment following damage to a region of the brain does not necessarily imply that the damaged area is wholly responsible for the cognitive process which is impaired, however. For example, in pure alexia, the ability to read is destroyed by a lesion damaging both the left visual field and the connection between the right visual field and the language areas (Broca's area and Wernicke's area). However, this does not mean one suffering from pure alexia is incapable of comprehending speech—merely that there is no connection between their working visual cortex and language areas—as is demonstrated by the fact that pure alexics can still write, speak, and even transcribe letters without understanding their meaning. [10]

Lesions to the fusiform gyrus often result in prosopagnosia, the inability to distinguish faces and other complex objects from each other. [11] Lesions in the amygdala would eliminate the enhanced activation seen in occipital and fusiform visual areas in response to fear with the area intact. Amygdala lesions change the functional pattern of activation to emotional stimuli in regions that are distant from the amygdala. [12]

Other lesions to the visual cortex have different effects depending on the location of the damage. Lesions to V1, for example, can cause blindsight in different areas of the brain depending on the size of the lesion and location relative to the calcarine fissure. [13] Lesions to V4 can cause color-blindness, [14] and bilateral lesions to MT/V5 can cause the loss of the ability to perceive motion. Lesions to the parietal lobes may result in agnosia, an inability to recognize complex objects, smells, or shapes, or amorphosynthesis, a loss of perception on the opposite side of the body. [15]

Non-localizing features Edit

Brain injuries have far-reaching and varied consequences due to the nature of the brain as the main source of bodily control. Brain-injured people commonly experience issues with memory. [16] This can be issues with either long or short-term memories depending on the location and severity of the injury. Sometimes memory can be improved through rehabilitation, although it can be permanent. Behavioral and personality changes are also commonly observed due to changes of the brain structure in areas controlling hormones or major emotions. Headaches and pain can also occur as a result of a brain injury either directly from the damage or due to neurological conditions stemming from the injury. Due to the changes in the brain as well as the issues associated with the change in physical and mental capacity, depression and low self-esteem are common side effects that can be treated with psychological help. Antidepressants must be used with caution in brain injury people due to the potential for undesired effects because of the already altered brain chemistry.

Long term psychological and physiological effects Edit

There are multiple responses of the body to brain injury, occurring at different times after the initial occurrence of damage, as the functions of the neurons, nerve tracts, or sections of the brain can be affected by damage. The immediate response can take many forms. Initially, there may be symptoms such as swelling, pain, bruising, or loss of consciousness. [17] Post-traumatic amnesia is also common with brain damage, as is temporary aphasia, or impairment of language. [18]

As time progresses, and the severity of injury becomes clear, there are further responses that may become apparent. Due to loss of blood flow or damaged tissue, sustained during the injury, amnesia and aphasia may become permanent, and apraxia has been documented in patients. Amnesia is a condition in which a person is unable to remember things. [19] Aphasia is the loss or impairment of word comprehension or use. Apraxia is a motor disorder caused by damage to the brain, and may be more common in those who have been left brain damaged, with loss of mechanical knowledge critical. [20] Headaches, occasional dizziness, and fatigue—all temporary symptoms of brain trauma—may become permanent, or may not disappear for a long time.

There are documented cases of lasting psychological effects as well, such as emotional changes often caused by damage to the various parts of the brain that control human emotions and behavior. [21] Individuals who have experienced emotional changes related to brain damage may have emotions that come very quickly and are very intense, but have very little lasting effect. [21] Emotional changes may not be triggered by a specific event, and can be a cause of stress to the injured party and their family and friends. [22] Often, counseling is suggested for those who experience this effect after their injury, and may be available as an individual or group session.

It is important to note that the long term psychological and physiological effects will vary by person and injury. For example, perinatal brain damage has been implicated in cases of neurodevelopmental impairments and psychiatric illnesses. If any concerning symptoms, signs, or changes to behaviors are occurring, a healthcare provider should be consulted.

Unlike some of the more obvious responses to brain damage, the body also has invisible physical responses which can be difficult to notice. These will generally be identified by a healthcare provider, especially as they are normal physical responses to brain damage. Cytokines are known to be induced in response to brain injury. [23] These have diverse actions that can cause, exacerbate, mediate and/or inhibit cellular injury and repair. TGFβ seems to exert primarily neuroprotective actions, whereas TNFα might contribute to neuronal injury and exert protective effects. IL-1 mediates ischaemic, excitotoxic, and traumatic brain injury, probably through multiple actions on glia, neurons, and the vasculature. Cytokines may be useful in order to discover novel therapeutic strategies. At the current time, they are already in clinical trials. [24]

Brain injuries can result from a number of conditions including: [25]

Chemotherapy Edit

Chemotherapy can cause brain damage to the neural stem cells and oligodendrocyte cells that produce myelin. Radiation and chemotherapy can lead to brain tissue damage by disrupting or stopping blood flow to the affected areas of the brain. This damage can cause long term effects such as but not limited to memory loss, confusion, and loss of cognitive function. The brain damage caused by radiation depends on where the brain tumor is located, the amount of radiation used, and the duration of the treatment. Radiosurgery can also lead to tissue damage that results in about 1 in 20 patients requiring a second operation to remove the damaged tissue. [29] [30]

Wernicke-Korsakoff syndrome Edit

Wernicke-Korsakoff syndrome can cause brain damage and results from a Vitamin B deficiency. This syndrome presents with two conditions, Wernicke’s encephalopathy and Korsakoff psychosis. Typically Wernicke’s encephalopathy precedes symptoms of Korsakoff psychosis. Wernicke’s encephalopathy causes bleeding in the thalamus or hypothalamus, which controls the nervous and endocrine system. Due to the bleeding, brain damage occurs causing problems with vision, coordination, and balance. Korsakoff psychosis typically follows after the symptoms of Wernicke’s decrease and result from chronic brain damage. [31] Korsakoff psychosis affect memory. Wernicke-Korsakoff syndrome is typically caused by chronic heavy alcohol use or by conditions that affect nutritional absorption, including colon cancer, eating disorders and gastric bypass. [32]

Iatrogenic Edit

Brain lesions are sometimes intentionally inflicted during neurosurgery, such as the carefully placed brain lesion used to treat epilepsy and other brain disorders. These lesions are induced by excision or by electric shocks (electrolytic lesions) to the exposed brain or commonly by infusion of excitotoxins to specific areas. [33]

Diffuse axonal Edit

Diffuse axonal injury is caused by shearing forces on the brain leading to lesions in the white matter tracts of the brain. [34] These shearing forces are seen in cases where the brain had a sharp rotational acceleration, and is caused by the difference in density between white matter and grey matter. [35]

Glasgow Coma Scale (GCS) is the most widely used scoring system used to assess the level of severity of a brain injury. This method is based on the objective observations of specific traits to determine the severity of a brain injury. It is based on three traits: eye opening, verbal response, and motor response, gauged as described below. [36] Based on the Glasgow Coma Scale severity is classified as follows, severe brain injuries score 3–8, moderate brain injuries score 9–12 and mild score 13–15. [36]

There are several imaging techniques that can aid in diagnosing and assessing the extent of brain damage, such as computed tomography (CT) scan, magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and single-photon emission tomography (SPECT). CT scans and MRI are the two techniques widely used and are most effective. CT scans can show brain bleeds, fractures of the skull, fluid build up in the brain that will lead to increased cranial pressure. MRI is able to better to detect smaller injuries, detect damage within the brain, diffuse axonal injury, injuries to the brainstem, posterior fossa, and subtemporal and subfrontal regions. However, patients with pacemakers, metallic implants, or other metal within their bodies are unable to have an MRI done. Typically the other imaging techniques are not used in a clinical setting because of the cost, lack of availability. [37]

Acute Edit

The treatment for emergency traumatic brain injuries focuses on assuring the person has enough oxygen from the brain blood supply, and on maintaining normal blood pressure to avoid further injuries of the head or neck. The person may need surgery to remove clotted blood or repair skull fractures, for which cutting a hole in the skull may be necessary. Medicines used for traumatic injuries are diuretics, anti-seizure or coma-inducing drugs. Diuretics reduce the fluid in tissues lowering the pressure on the brain. In the first week after a traumatic brain injury, a person may have a risk of seizures, which anti-seizure drugs help prevent. Coma-inducing drugs may be used during surgery to reduce impairments and restore blood flow.

In the case of brain damage from traumatic brain injury, dexamethasone and/or Mannitol may be used. [38]

Chronic Edit

Various professions may be involved in the medical care and rehabilitation of someone suffering impairment after a brain injury. Neurologists, neurosurgeons, and physiatrists are physicians specialising in treating brain injury. Neuropsychologists (especially clinical neuropsychologists) are psychologists specialising in understanding the effects of brain injury and may be involved in assessing the severity or creating rehabilitation strategies. Occupational therapists may be involved in running rehabilitation programs to help restore lost function or help re-learn essential skills. Registered nurses, such as those working in hospital intensive care units, are able to maintain the health of the severely brain-injured with constant administration of medication and neurological monitoring, including the use of the Glasgow Coma Scale used by other health professionals to quantify extent of orientation. [39]

Physiotherapists also play a significant role in rehabilitation after a brain injury. In the case of a traumatic brain injury (TBIs), physiotherapy treatment during the post-acute phase may include: sensory stimulation, serial casting and splinting, fitness and aerobic training, and functional training. [40] Sensory stimulation refers to regaining sensory perception through the use of modalities. There is no evidence to support the efficacy of this intervention. [41] Serial casting and splinting are often used to reduce soft tissue contractures and muscle tone. Evidence based research reveals that serial casting can be used to increase passive range of motion (PROM) and decrease spasticity. [41] Studies also report that fitness and aerobic training will increase cardiovascular fitness however the benefits will not be transferred to the functional level. [42] Functional training may also be used to treat patients with TBIs. To date, no studies supports the efficacy of sit to stand training, arm ability training and body weight support systems (BWS). [43] [44] Overall, studies suggest that patients with TBIs who participate in more intense rehabilitation programs will see greater benefits in functional skills. [42] More research is required to better understand the efficacy of the treatments mentioned above. [45]

Prognosis, or the likely progress of a disorder, depends on the nature, location, and cause of the brain damage (see Traumatic brain injury, Focal and diffuse brain injury, Primary and secondary brain injury).

In general, neuroregeneration can occur in the peripheral nervous system but is much rarer and more difficult to assist in the central nervous system (brain or spinal cord). However, in neural development in humans, areas of the brain can learn to compensate for other damaged areas, and may increase in size and complexity and even change function, just as someone who loses a sense may gain increased acuity in another sense – a process termed neuroplasticity. [46]

There are many misconceptions that revolve around brain injuries and brain damage. One misconception is that if someone has brain damage then they cannot fully recover. Recovery depends a variety of factors such as severity and location. Testing is done to note severity and location. Not everyone fully heals from brain damage, but it is possible to have a full recovery. Brain injuries are very hard to predict in outcome. Many tests and specialists are needed to determine the likelihood of the prognosis. People with minor brain damage can have debilitating side effects not just severe brain damage has debilitating effects. [47] The side- effects of a brain injury depend on location and the body’s response to injury. [47] Even a mild concussion can have long term effects that may not resolve. [48] Another misconception is that children heal better from brain damage. Children are at greater risk for injury due to lack of maturity. It makes future development hard to predict. [48] [ dead link ] This is because different cortical areas mature at different stages, with some major cell populations and their corresponding cognitive faculties remaining unrefined until early adulthood. In the case of a child with frontal brain injury, for example, the impact of the damage may be undetectable until that child fails to develop normal executive functions in his or her late teens and early twenties. [49]

The foundation for understanding human behavior and brain injury can be attributed to the case of Phineas Gage and the famous case studies by Paul Broca. The first case study on Phineas Gage’s head injury is one of the most astonishing brain injuries in history. In 1848, Phineas Gage was paving way for a new railroad line when he encountered an accidental explosion of a tamping iron straight through his frontal lobe. Gage observed to be intellectually unaffected but exemplified post injury behavioral deficits. These deficits include: becoming sporadic, disrespectful, extremely profane, and gave no regard for other workers. Gage started having seizures in February, dying only four months later on May 21, 1860. [50]

Ten years later, Paul Broca examined two patients exhibiting impaired speech due to frontal lobe injuries. Broca’s first patient lacked productive speech. He saw this as an opportunity to address language localization. It wasn't until Leborgne, formally known as "tan", died when Broca confirmed the frontal lobe lesion from an autopsy. The second patient had similar speech impairments, supporting his findings on language localization. The results of both cases became a vital verification of the relationship between speech and the left cerebral hemisphere. The affected areas are known today as Broca’s area and Broca’s Aphasia. [51]

A few years later, a German neuroscientist, Carl Wernicke, consulted on a stroke patient. The patient experienced neither speech nor hearing impairments, but suffered from a few brain deficits. These deficits included: lacking the ability to comprehend what was spoken to him and the words written down. After his death, Wernicke examined his autopsy that found a lesion located in the left temporal region. This area became known as Wernicke's area. Wernicke later hypothesized the relationship between Wernicke's area and Broca's area, which was proven fact. [52]


What Causes Brain Damage?

When the brain is starved of oxygen for a prolonged period of time, brain damage may occur. Brain damage can occur as a result of a wide range of injuries, illnesses, or conditions. Because of high-risk behaviors, males between ages 15 and 24 are most vulnerable. Young children and the elderly also have a higher risk.

Causes of traumatic brain injury include:

  • Car accidents
  • Blows to the head
  • Sports injuries
  • Falls or accidents
  • Physical violence

Causes of acquired brain injury include:

  • Poisoning or exposure to toxic substances
  • Infection
  • Strangulation, choking, or drowning
  • Stroke
  • Tumors
  • Aneurysms
  • Neurological illnesses
  • Abuse of illegal drugs

Introduction

Beginning with the discovery of the left-hemispheric dominance of language (Broca, 1861 Dax, 1865) it has now been shown that practically all higher functions including memory, learning, perception, spatial cognition, attention, complex motor skills, and emotion processing show some degree of hemispheric specialization (Hellige, 1993 Davidson and Hugdahl, 1995). At first, lateralization was believed to be a unique human feature (Crow, 2002) but in the meantime it has been documented in a wide range of species (Vallortigara and Rogers, 2005). Brain asymmetries in humans, however, are typically more pronounced than in animals and it has been argued that they gave rise to our superior verbal and intellectual skills (Corballis, 1991, 2009). Previous research has shown that the degree of lateralization in humans is subject to inter- and intraindividual differences. For example, some individuals show strong left-hemispheric language lateralization, others strong-right-hemispheric language lateralization, and still others possess a more bilateral language representation (Knecht et al., 2000). Even within individuals lateralization changes as a function of, for example, sex hormones (Hausmann and Güntürkün, 2000 Bayer and Hausmann, 2009 Hjelmervik et al., 2012) or emotional states (Papousek et al., 2011, 2012). However, not much is known about how degree of lateralization and performance in selected functions are related, which we refer to as the 𠇊symmetry-performance relationship”, and the few studies available provide incoherent results. For example, Everts et al. (2009) found that a stronger language lateralization, determined with functional magnetic resonance imaging (fMRI), was correlated with a higher verbal IQ. Chiarello et al. (2009) used visual half-field paradigms to assess language lateralization and also found a positive correlation between the degree of lateralization in these tasks and reading skills. On the other hand, there are also studies showing that performance deteriorates with increasing asymmetry. For example, less lateralized participants outperform more lateralized individuals in a face discrimination task (Ladavas and Umilta, 1983) and when two cognitive tasks (i.e., face discrimination and lexical decision) are performed in parallel (Hirnstein et al., 2008). Moreover, individuals with higher degrees of language lateralization as determined with fMRI (van Ettinger-Veenstra et al., 2010) or magnetic resonance diffusion tensor imaging (Catani et al., 2007) performed better on tests assessing verbal abilities (van Ettinger-Veenstra et al., 2010) or verbal memory (Catani et al., 2007) than individuals with lower degrees of lateralization. The inconsistent findings are neatly illustrated by Razafimandimby et al. (2011) who found that verb generation correlated both positively with precuneus asymmetry and negatively with cerebellum asymmetry (as determined with fMRI).

Boles et al. (2008) carried out the most extensive investigations regarding the asymmetry-performance relationship. They had data from several visual half-field and dichotic listening (DL) tasks that assessed various verbal and non-verbal cognitive functions. To obtain the asymmetry-performance relationship, they correlated the degree of lateralization derived from these tasks with the overall accuracy (or reaction times) – also derived from these tasks. The results are in line with the inconsistent findings described above. Boles et al. (2008) found positive asymmetry-performance relationships in four tasks assessing auditory linguistic and spatial positional functions. Negative relationships emerged in seven tasks assessing planar categorical, spatial emergent, spatial quantitative, and visual lexical functions. The authors concluded that the asymmetry-performance relationship is function-dependent and suggested a neurodevelopmental model according to which functions that lateralize very early (until 5 years of age) and very late in the ontogenetic development (after 11 years of age) yield positive asymmetry-performance correlations. Functions that lateralize at intermediate stages on the other hand show negative correlations.

The neurodevelopmental theory of Boles et al. (2008) may account for some of the strikingly inconsistent results. However, there are a number of methodological pitfalls which might contribute to the inconsistencies above. One of these issues is the “task purity problem” (Boles and Barth, 2011). If lateralization is assessed with one task and then correlated with performance in another task, correlations between lateralization and performance might be confounded by a third variable and do not reveal the pure asymmetry-performance relationship (Boles and Barth, 2011 but see also the reply of Chiarello et al., 2011). If one derives the performance and lateralization from the same task, however, one is faced with the problem of interdependency between left (L) and right (R) scores. Both the overall accuracy (i.e., sum or mean of L and R) and the degree of lateralization [i.e., (R - L)/(R + L) or (R - L)/(200 - R - L)] are derived from the same L and R scores. Given that L and R scores are typically correlated with each other, there is a risk that the asymmetry-performance relationship is simply the result of, or at least confounded with, this correlation between L and R scores.

The vast majority of studies that investigated the asymmetry-performance relationship in one task do not address the interdependency issue. To solve this problem, Leask and Crow (1997, 2006) developed a method that compares the asymmetry-performance relationship based on R and L scores with reference models in which R and L scores have been modeled such that they do not correlate. Another advantage of this procedure is that it is data-driven and can detect any form of asymmetry-performance relationships. Most studies simply assume linear asymmetry-performance relationships. By applying the procedure suggested by Leask and Crow (1997, 2006) to data from two visual half-field paradigms (i.e., word recognition, face discrimination), Hirnstein et al. (2010) found an inverted u-shaped association between asymmetry and performance. That is, individuals with a symmetric brain organization performed best and performance deteriorated with increasing left or right lateralization. However, the calculation of the degree of asymmetry [(R - L)/(R + L)] in this study has been criticized by Boles and Barth (2011).

It should be noted that almost all of the aforementioned studies that investigated the asymmetry-performance relationship tested right-handed adults (Catani et al., 2007 Boles et al., 2008 Hirnstein et al., 2010 van Ettinger-Veenstra et al., 2010) leaving it unclear whether the findings also apply to other populations such as left-handers, children and adolescents, which are assumed to be less lateralized in verbal and non-verbal functions (e.g., Rasmussen and Milner, 1977 Everts et al., 2009). In general, interindividual differences in the asymmetry-performance relationship are hardly investigated even though there are hints that they exist. Chiarello et al. (2009) reported that the positive correlation between language lateralization and reading skills was stronger in individuals with a consistent hand preference as compared to participants with an inconsistent hand preference. Hirnstein et al. (2010) found that males with a strong left-hemispheric lateralization in a face discrimination task performed rather poorly, while females with a strong left-hemispheric lateralization performed rather well. Thus the asymmetry-performance relationship might also be sex-specific. Finally, little is known about age effects. Only Barth et al. (2012) studied whether the positive asymmetry-performance relationship that they found in a verbal DL task in adults (Boles et al., 2008) also emerged in children. Moreover, they examined whether, in accordance with their neurodevelopmental model, adults but not children showed a negative relationship in emotional face discrimination. While the results mostly confirmed their hypotheses, some of the correlations did not reach statistical significance. According to the authors this was due to the relatively small sample size (25 children, 32 adults) emphasizing that sufficient statistical power is needed to reveal the asymmetry-performance relationship.

With some exceptions (Boles et al., 2008 van Ettinger-Veenstra et al., 2010 Barth et al., 2012) most of the studies on the asymmetry-performance relationship used visual tasks and visual asymmetry (Ladavas and Umilta, 1983 Boles et al., 2008 Hirnstein et al., 2008, 2010 Chiarello et al., 2009). Since the relationship between brain asymmetry and task performance should be generic and not dependent on sensory modality, similar relationships should be possible to obtain in the auditory modality, using, e.g., a DL task, which is perhaps the most frequently used task for assessing hemispheric asymmetry (see Hugdahl, 2011 Kimura, 2011 for recent overviews of the use of DL in asymmetry research). Over the years, Kenneth Hugdahl and our research group at the University of Bergen have built up a database with DL data, which now comprises 1839 individuals (see Hugdahl, 2003 for a description of the database). The sample covers a wide age range (5� years), has a balanced sex ratio (927 females, 912 males) and a proportion of non-right-handers of 8.9% which is close to the 10% typically observed in the general population (McManus, 2002). The large number of participants allows a comprehensive examination of the asymmetry-performance relationship and further provides an ideal opportunity to also take into account sex, handedness, and age effects. Two previous studies found that overall accuracy in verbal DL increased as asymmetries became stronger (Boles et al., 2008 Barth et al., 2012), however, leaving the interdependency issue of L and R scores unsolved. Using the approach by Boles et al. (2008), the present study examined first whether we could replicate the positive asymmetry-performance relationship found by this group. In a second step, we applied the approach by Leask and Crow (1997, 2006) which controls for the interdependency issues. By applying this approach, we also took sex, handedness, and age into account. In line with Boles et al. (2008), we hypothesized that individuals with stronger ear advantages (corresponding to a stronger degree of language lateralization) would generally report more stimuli correctly. Consequently, non-right-handers, women, and children, who are assumed to be less lateralized for language, should generally report less syllables correctly. However, this requires asymmetry-performance relationships to be consistent across all subsamples.


This Is How Your Brain Reacts To Losing A Loved One

Grief can be healthy&mdashbut it changes your brain, too. These steps ensure a strong recovery.

Recently, my 58-year-old younger brother, a fit-and-sturdy Marine combat veteran, was diagnosed with lung cancer and died. Two weeks later, after an almost entirely disease-free life, I had to undergo eye surgery for cataracts. Since then, I've been thinking a lot about the inevitable setbacks we all encounter and how our brains deal with them. (Boost your memory and age-proof your mind with these natural solutions.)

Researchers completed an intriguing study that illustrates just how profound and widespread the effect of negative personal events can be and how your brain reacts to grief. Three finance professors from major business schools tracked the performance of 75,000 Danish companies in the 2 years before and after the CEO had experienced a family death. Financial performance declined 20% after the loss of a child, 15% after the death of a spouse, and almost 10% after the demise of any other family member.

Indeed, when brain imaging studies are done on people who are grieving, increased activity is seen along a broad network of neurons. These link areas associated not only with mood but also with memory, perception, conceptualization, and even the regulation of the heart, the digestive system, and other organs. This shows the pervasive impact loss or even disappointment can have. And the more we dwell on negative thoughts, the more developed these neural pathways become. The result can be chronic preoccupation, sadness, or even depression.

So how can we learn to deal with loss, disappointment, and everyday setbacks more constructively? Keep in mind these coping strategies for grief, which are working for me:

Be on the alert for "intruders." As soon as you recognize an intrusive negative thought, visualize a stop sign. Even go so far as to say "Stop!" if it helps. Or try wearing a rubber band around your wrist and snap yourself out of it.

Schedule your sad memories. Just as you don't immediately indulge every pang of hunger, put off sad remembrances for a time when you don't need to be productive or engaged (say, during your lunch hour). Never examine such thoughts before bed, however. This is an invitation for negativity and blame to gather strength. Prior to sleep, electrical activity diminishes in brain regions associated with analytical reasoning, and we become less objective.

Don't tolerate self-accusing or superstitious thoughts. Examples of these would be If only I had been, or Bad things happen in threes. Such thinking has no logical basis or benefit.

View setbacks as opportunities. Effectively dealing with difficulties that don't incapacitate you will make you stronger.

Finally, keep in mind that during these emotionally vulnerable times, we all create illusions. We focus almost exclusively on how wonderful those who've disappeared from our lives made us feel, and we convince ourselves that no one could ever affect us like that again. I miss my brother, no doubt about it. I know that I can't avoid illness and death in my life, but I can choose how to deal with them. I'm lucky to have known my brother for 58 years, but I'm not going to dwell on the thought that our time together could have been longer.


What Occurs in the Brain When You Multitask

Humans are capable of doing two things at a time, especially when one of those activities is so ingrained that it can be done on autopilot.

Most of us can carry on a conversation while walking or drink coffee while driving — no problem.

But what we can’t do is learn or concentrate on two things at once.

" Distracted walking causes pedestrians to get hit by cars, fall off bridges, and stumble onto subway tracks.

When the brain is presented with two tasks at once, it quickly toggles back and forth between them.

But when your brain receives more information than it can process, an area of your brain called the posterior lateral prefrontal cortex (pLPFC) takes over. (3)

It acts as a hub for routing new stimuli.

Your pLPFC will line these stimuli up in a queue, rather than trying to handle them simultaneously.

But if new stimuli come too rapidly, the pLPFC simply queues up the first two pieces of information and ignores the rest.

A quality brain supplement can make a big difference.

Dr. Pat | Be Brain Fit


Teen Drinking May Cause Irreversible Brain Damage

The red specks highlight where the integrity of the brain's white matter is significantly less in the teens who binge drink, compared to those who do not. Courtesy of Susan Tapert/Tim McQueeny, UCSD hide caption

The red specks highlight where the integrity of the brain's white matter is significantly less in the teens who binge drink, compared to those who do not.

Courtesy of Susan Tapert/Tim McQueeny, UCSD

For teenagers, the effects of a drunken night out may linger long after the hangover wears off.

A recent study led by neuroscientist Susan Tapert of the University of California, San Diego compared the brain scans of teens who drink heavily with the scans of teens who don't.

Tapert's team found damaged nerve tissue in the brains of the teens who drank. The researchers believe this damage negatively affects attention span in boys, and girls' ability to comprehend and interpret visual information.

"First of all, the adolescent brain is still undergoing several maturational processes that render it more vulnerable to some of the effects of substances," Tapert says.

In other words, key areas of the brain are still under construction during the adolescent years, and are more sensitive to the toxic effects of drugs and alcohol.

Damage to the brain of a teenage drinker, top view Courtesy of Susan Tapert/Tim McQueeny, UCSD hide caption

Thought, Memory Functions Affected

For the study, published last month in the journal Psychology of Addictive Behaviors, Tapert looked at 12- to 14-year-olds before they used any alcohol or drugs. Over time, some of the kids started to drink, a few rather heavily — consuming four or five drinks per occasion, two or three times a month — classic binge drinking behavior in teens.

Comparing the young people who drank heavily with those who remained non-drinkers, Tapert's team found that the binge drinkers did worse on thinking and memory tests. There was also a distinct gender difference.

"For girls who had been engaging in heavy drinking during adolescence, it looks like they're performing more poorly on tests of spatial functioning, which links to mathematics, engineering kinds of functions," Tapert says.

"For boys who engaged in binge drinking during adolescence, we see poor performance on tests of attention — so being able to focus on something that might be somewhat boring, for a sustained period of time," Tapert says. "The magnitude of the difference is 10 percent. I like to think of it as the difference between an A and a B."

Teenage Tendency To Experiment To Blame

Pediatrician and brain researcher Ron Dahl from the University of Pittsburgh notes that adolescents seem to have a higher tolerance for the negative immediate effects of binge drinking, such as feeling ill and nauseated.

"Which makes it easier to consume higher amounts and enjoy some of the positive aspects," Dahl says. "But, of course, that also creates a liability for the spiral of addiction and binge use of these substances."

He adds that there is a unique feature of the teenage brain that drives much behavior during adolescence: The teen brain is primed and ready for intense, all-consuming learning.

"Becoming passionate about a particular activity, a particular sport, passionate about literature or changing the world or a particular religion" is a normal, predictable part of being a teenager, he says.

"But those same tendencies to explore and try new things and try on new identities may also increase the likelihood of starting on negative pathways," he adds.

Damaged Brain Tissue

Tapert wanted to find out in what way binge drinking affects a teen's developing brain. So using brain imaging, she focused on the white matter, or nerve tissue, of the brain.

"White matter is very important for the relay of information between brain cells and we know that it is continuing to develop during adolescence," Tapert says.

So Tapert imaged the brains of two groups of high school students: binge drinkers and a matched group of teens with no history of binge drinking. She reports in her recent study a marked difference in the white matter of the binge drinkers.

"They appeared to have a number of little dings throughout their brains' white matter, indicating poor quality," Tapert says.

And poor quality of the brain's white matter indicates poor, inefficient communication between brain cells.

"These results were actually surprising to me because the binge drinking kids hadn't, in fact, engaged in a great deal of binge drinking. They were drinking on average once or twice a month, but when they did drink, it was to a relatively high quantity of at least four or five drinks an occasion," she says.

In another study, Tapert reported abnormal functioning in the hippocampus — a key area for memory formation — in teen binge drinkers. Reflecting their abnormal brain scans, the teen drinkers did more poorly on learning verbal material than their non-drinking counterparts.

What remains unknown, says Tapert, is if the cognitive downward slide in teenage binge drinkers is reversible.


Multitasking Damages Your Brain And Career, New Studies Suggest

You've likely heard that multitasking is problematic, but new studies show that it kills your performance and may even damage your brain.

Research conducted at Stanford University found that multitasking is less productive than doing a single thing at a time. The researchers also found that people who are regularly bombarded with several streams of electronic information cannot pay attention, recall information, or switch from one job to another as well as those who complete one task at a time.

A Special Skill?

But what if some people have a special gift for multitasking? The Stanford researchers compared groups of people based on their tendency to multitask and their belief that it helps their performance. They found that heavy multitaskers—those who multitask a lot and feel that it boosts their performance—were actually worse at multitasking than those who like to do a single thing at a time. The frequent multitaskers performed worse because they had more trouble organizing their thoughts and filtering out irrelevant information, and they were slower at switching from one task to another. Ouch.

Multitasking reduces your efficiency and performance because your brain can only focus on one thing at a time. When you try to do two things at once, your brain lacks the capacity to perform both tasks successfully.

Multitasking Lowers IQ

Research also shows that, in addition to slowing you down, multitasking lowers your IQ. A study at the University of London found that participants who multitasked during cognitive tasks experienced IQ score declines that were similar to what they'd expect if they had smoked marijuana or stayed up all night. IQ drops of 15 points for multitasking men lowered their scores to the average range of an 8-year-old child.

So the next time you're writing your boss an email during a meeting, remember that your cognitive capacity is being diminished to the point that you might as well let an 8-year-old write it for you.

Brain Damage From Multitasking

It was long believed that cognitive impairment from multitasking was temporary, but new research suggests otherwise. Researchers at the University of Sussex in the UK compared the amount of time people spend on multiple devices (such as texting while watching TV) to MRI scans of their brains. They found that high multitaskers had less brain density in the anterior cingulate cortex, a region responsible for empathy as well as cognitive and emotional control.

While more research is needed to determine if multitasking is physically damaging the brain (versus existing brain damage that predisposes people to multitask), it's clear that multitasking has negative effects. Neuroscientist Kep Kee Loh, the study’s lead author, explained the implications: "I feel that it is important to create an awareness that the way we are interacting with the devices might be changing the way we think and these changes might be occurring at the level of brain structure.”

Learning From Multitasking

If you’re prone to multitasking, this is not a habit you’ll want to indulge—it clearly slows you down and decreases the quality of your work. Even if it doesn’t cause brain damage, allowing yourself to multitask will fuel any existing difficulties you have with concentration, organization, and attention to detail.

Multitasking in meetings and other social settings indicates low self- and social-awareness, two emotional intelligence (EQ) skills that are critical to success at work. TalentSmart has tested more than a million people and found that 90% of top performers have high EQs. If multitasking does indeed damage the anterior cingulate cortex (a key brain region for EQ) as current research suggests, it will lower your EQ in the process.

So every time you multitask you aren't just harming your performance in the moment you may very well be damaging an area of your brain that's critical to your future success at work.