Inside The Neocortex

The neocortex (Latin for “new bark” or “new rind”) is part of the cerebral cortex of the mammalian brain.  In humans, it is involved in “higher functions” such as sensory perception, generation of motor commands, spatial reasoning, conscious thought and language.

In an overview of the structure of the mammalian neocortex, Professor of Neurobiology, Clay Reid explains how the mammalian cortex is organized in a hierarchy, describing the columnar principle and canonical microcircuits.

This full-length, undergraduate-level lecture is the third of a 12-part series entitled Coding & Vision 101, produced by the Allen Institute for Brain Science as an educational resource for the community.

Weekly Neuroscience Update

medium_46044113Advice to “sleep on it” before making a big decision may be wise, according to new brain-imaging research.

Scientists from the University of Southampton have identified the molecular system that contributes to the harmful inflammatory reaction in the brain during neurodegenerative diseases.An important aspect of chronic neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, Huntington’s or prion disease, is the generation of an innate within the brain. Results from the study open new avenues for the regulation of the inflammatory reaction and provide new insights into the understanding of the biology of , which play a leading role in the development and maintenance of this reaction.

A study conducted at the University of Granada and the University of York in Toronto, Canada, has revealed that bilingual children develop a better working memory –which holds, processes and updates information over short periods of time– than monolingual children.

Good mental health and clear thinking depend upon our ability to store and manipulate thoughts on a sort of “mental sketch pad.” In a new study, Yale School of Medicine researchers describe the molecular basis of this ability — the hallmark of human cognition — and describe how a breakdown of the system contributes to diseases such as schizophrenia and Alzheimer’s disease.

Your eyes aren’t just advanced visual systems capturing images of what’s around you. New research published in the Journal of Neuroscience shows that when our eyes perceive visual stimuli, it gets encoded in our brains in ways that change our emotional reactions.

In a pair of new papers, researchers at the University of California, San Diego School of Medicine and the Royal Netherlands Academy of Arts and Sciences upend a long-held view about the basic functioning of a key receptor molecule involved in signaling between neurons, and describe how a compound linked to Alzheimer’s disease impacts that receptor and weakens synaptic connections between brain cells.

Fear responses can only be erased when people learn something new while retrieving the fear memory. This is the conclusion of a study conducted by scientists from the University of Amsterdam (UvA) and published in the leading journal Science.

Injuries that result in chronic pain, such as limb injuries, and those unrelated to the brain are associated with epigenetic changes in the brain which persist months after the injury, according to researchers at McGill University.

Montreal researchers find that music lessons before age seven create stronger connections in the brain.

A team of political scientists and neuroscientists has shown that liberals and conservatives use different parts of the brain when they make risky decisions, and these regions can be used to predict which political party a person prefers.

Did roid rage lead Oscar Pistorius to murder his girlfriend?

Oscar Pistorius, the South African Paralympic athlete has reportedly been tested for steroids after the banned drug was found at the home where he is accused of murdering his girlfriend.  According to newspaper reports, police asked for blood taken from Mr Pistorius to be tested for steroids, in anticipation that his defence team might claim he acted in “roid rage” – an aggressive condition associated with taking large doses of performance-enhancing drugs.

Reading these reports prompted me to re-visit a blog I wrote in 2011 on Anders Baring Brevik’s Oslo killings.  . In a 1500-page manifesto,  which he wrote in advance of his attack, he  describes how he will be on a “steroid rush”and describes the extensive use of steroids and protein drinks to provide him with more energy for his killing spree.

Playing with fire

Steroids are dangerous drugs, and when used inappropriately, they can cause serious behavioural and psychiatric problems – possibly by interfering with the brain’s ability to regulate a hormone called vasopressin – which is linked to aggression1.  Research has shown that the inappropriate use of anabolic steroids – man-made versions of the male sex hormone testosterone – can have catastrophic behavioural consequences including aggression (also known as roid rage or the “steroid rush” mentioned in Brevik’s manifesto) such as fighting, physical and sexual assault, armed robbery and property crimes such as burglary and vandalism.  The full-blown aggression can last for up to two weeks after withdrawal. As if this is not bad enough, the psychiatric consequences of inappropriate use of anabolic steroids include jealousy, irritability, deluded thinking, mood swings and bad judgement due to a feeling of invincibility.  Why would anyone even dream of taking such a drug – I hear you ask?

The upside of anabolic steroids

Anabolic steroids are powerful body-building drugs. They promote rapid growth of muscle bone, the larynx (voice box) and a decrease in body fat leading to increased strength and endurance. For this reason anabolic steroid abuse is widespread among athletes, bodybuilders, weightlifters and football players at all levels. However, in this case anabolic steroids are taken to simply replace the discipline required for the long hours of training needed to build up more muscle – as nature intended – and are thus a “shortcut” to an athletic body. These bulking-up effects of steroids on muscle can boost confidence and strength leading the abuser to overlook the potential serious long-term damage that these substances can cause. These drugs are also abused by people who believe that they look underweight, are the wrong shape, to stop being bullied, beaten up or sexually attacked.

Anabolic steroids are very effective in treating conditions such as delayed puberty, some types of impotence, body wasting in patients with AIDS, and other diseases that occur when the body produces abnormally low amounts of testosterone. However, the doses prescribed to treat these medical conditions are 10 to 100 times lower than the doses that are abused for performance enhancement usually by some athletes, nightclub bouncers and others interested in beefing-up their muscles.

Why are anabolic steroids addictive?

By enhancing certain types of performance or appearance anabolic steroid abuse is increasing in adolescents and most rapidly among females. Abuse of anabolic steroids differs from the abuse of other illegal drugs because the initial use of anabolic steroids is not driven by the immediate euphoria that accompanies most drugs of abuse, such as cocaine, heroin, alcohol and marijuana, but by the desire of the abuser to change their appearance and performance, characteristics of great importance to adolescents and young adults.

Route of administration

They can be taken orally (by mouth) as tablets or capsules (Anadrol® [oxymetholone], Oxandrin® [oxandrolone], Dianabol® [methandrostenolone], Winstrol® [stanozolol], and others), by injection into muscles (Deca-Durabolin® [nandrolone decanoate], Durabolin® [nandrolone phenpropionate], Depo-Testosterone® [testosterone cypionate], Equipoise® [boldenone undecylenate], and others) or by ointment preparations rubbed into the skin and are often taken together with drinks rich in protein – the building blocks of muscle.  Health food supplements such as dehydroepiandrosterone (DHEA) and androsterone (street name Andro) arenot anabolic steroids.

Enough is never enough

Anabolic steroids are legally available only on prescription and for the illegal market are manufactured in illegal laboratories (poor quality), smuggled in from other countries or stolen from hospitals and pharmacies. One of the hallmarks of addiction is an inability to control drug intake and anabolic steroid abuse is no exception to this. Abusers use two ways of maximizing the effect of the drug on muscle growth – stacking and pyramiding. Both can cause very high levels of steroids to accumulate quickly in the body resulting in acute behavioural and psychiatric problems such as the controlled rage or “steroid rush” described by Brevik.

Stack ‘em high

Stacking is the term used when abusers take two or more anabolic steroids together, mixing oral and/or injectable types, sometimes adding drugs such as stimulants (caffeine, nicotine) or painkillers (codeine, morphine, heroin, diazepam).  Stacking is thought to produce a greater effect on muscle size than could be obtained by simply increasing the dose of a single drug.

The ultimate pyramid scheme

In a separate procedure called pyramiding at the beginning of a cycle, the abuser starts with low doses of the stacked substances – gradually increasing the doses for 6 to 12 weeks.  In the second half of the cycle, the doses are slowly decreased to zero.  This is followed by a second cycle during which the person continues to train, but without drugs. Abusers believe that pyramiding allows the body time to adjust to the high doses, and the drug-free cycle allows time for the body’s natural hormonal system to recover.

Life is not just about winning

Most adolescents already know that anabolic steroids build muscles and can increase athletic prowess and a failure to acknowledge these potential benefits creates a credibility problem and can actually make youths more likely to try the drugs.  Young people need to see the benefits of working with what nature has provided – such as the importance of proper nutrition and exercise and other techniques for improving performance – and not “cheat” by using steroids and thereby exposing themselves to the negative side-effects associated with these drugs.  Participating in sports offers many benefits, but young people and adults shouldn’t take unnecessary health risks in an effort to win.  By giving a balanced picture of what these drugs can do for you and to you I hope that this blog post will help in those prevention and education efforts by reaching young people, their parents, and others who may think that anabolic steroids are a harmless way to ‘bulk up’ or achieve athletic goals.

  1. Plasticity in anterior hypothalamic vasopressin correlates with aggression during anabolic-androgenic steroid withdrawal in hamsters.  Grimes, Jill M.; Ricci, Lesley A.; Melloni, Richard H., Jr.  Behavioral Neuroscience, Vol 120(1), Feb 2006, 115-124. doi:10.1037/0735-7044.120.1.115

For those interested in the topic of steroid abuse more information can be found at:

www.steroidabuse.gov

http://www.nida.nih.gov/Drugpages/PSAhome.html

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Inside the Mammalian Visual System

From the retina to the superior colliculus, the lateral geniculate nucleus into primary visual cortex and beyond, R. Clay Reid gives a tour of the mammalian visual system highlighting the Nobel-prize winning discoveries of Hubel & Wiesel. This is the first lecture of a 12-part series entitled Coding & Vision 101, produced by the Allen Institute for Brain Science as an educational resource for the community.

Brain networks of social comparison

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A new study of the neural correlates of social comparison, that is, the process of comparing oneself to other people tests the hypothesis that social comparisons are supported by partly dissociated networks, depending on whether the dimension under comparison concerns a physical or a psychological attribute.

Researchers measured brain activity with functional MRI, with participants comparing their own height or intelligence to that of individuals they personally know. Height comparisons were associated with higher activity in a frontoparietal network involved in spatial and numerical cognition. Conversely, intelligence comparisons recruited a network of midline areas that have been previously implicated in the attribution of mental states to oneself and others (Theory of mind). These findings suggest that social comparisons rely on diverse domain-specific mechanisms rather than on one unitary process.

Source: http://www.ncbi.nlm.nih.gov/pubmed/23407275

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How your brain remembers

How do you remember where you parked your car? How do you know if you’re moving in the right direction? In this video, neuroscientist Neil Burgess  who studies the neural mechanisms that map the space around us, explains how they link to memory and imagination.

Weekly Neuroscience Update

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The brains of deaf people reorganize not only to compensate for the loss of hearing, but also to process language from visual stimuli—sign language, according to a study published  in Nature Communications. Despite this reorganization for interpreting visual language, however, language processing is still completed in the same brain region.

Our love of music and appreciation of musical harmony is learnt and not based on natural ability – a new study by University of Melbourne researchers has found.

For many patients with difficult-to-treat neuropathic pain, deep brain stimulation (DBS) can lead to long-term improvement in pain scores and other outcomes, according to a study in the February issue of Neurosurgery.

New brain imaging research from Carnegie Mellon University provides some of the first evidence showing how the brain unconsciously processes decision information in ways that lead to improved decision making. Published in the journal Social Cognitive and Affective Neuroscience, the study found that the brain regions responsible for making decisions continue to be active even when the conscious brain is distracted with a different task.

An interdisciplinary team of researchers has found a new way to influence the vital serotonin signaling system—possibly leading to more effective medications with fewer side effects.

Researchers at the University of Pittsburgh School of Medicine and UPMC describe in PLoS ONE how an electrode array sitting on top of the brain enabled a 30-year-old paralyzed man to control the movement of a character on a computer screen in three dimensions with just his thoughts. It also enabled him to move a robot arm to touch a friend’s hand for the first time in the seven years since he was injured in a motorcycle accident.

Researchers have discovered a molecule that accumulates with age and inhibits the formation of new neurons. The finding might help scientists design therapies to prevent age-related cognitive decline.

Wearing a nerve stimulator for 20 minutes a day may be a new option for migraine sufferers, according to new research published in the February 6, 2013, online issue of Neurology®, the medical journal of the American Academy of Neurology.

photo credit: Hindrik S via photopin cc

Weekly Neuroscience Update

medium_5188555841Addiction to cigarettes and other drugs may result from abnormal wiring in the brain’s frontal cortex, an area critical for self-control, a new study finds.

An international study has made a major contribution to the ongoing scientific debate about how processes in the human brain support memory and recognition. The study used a rare technique in which data was obtained from within the brain itself, using electrodes placed inside the brains of surgery patients. The study used a rare technique in which data was obtained from within the brain itself, using electrodes placed inside the brains of .

Scientists have for the first time visualized the molecular changes in a critical cell death protein that force cells to die. The finding provides important insights into how cell death occurs, and could lead to new classes of medicines that control whether diseased cells live or die.

Differences in the physical connections of the brain are at the root of what make people think and behave differently from one another. Researchers reporting in the February 6 issue of the Cell Press journal Neuron shed new light on the details of this phenomenon, mapping the exact brain regions where individual differences occur. Their findings reveal that individuals’ brain connectivity varies more in areas that relate to integrating information than in areas for initial perception of the world.
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Weekly Neuroscience Update

xbox

When selecting a video game to play, opting to turn on your Wii may provide a different experience than playing your Xbox, according to a study from Mississippi State University.

Excessive alcohol use accounts for 4% of the global burden of disease, and binge drinking particularly is becoming an increasing health issue. A new review article published Cortex highlights the significant changes in brain function and structure that can be caused by alcohol misuse in young people.

Working with patients with electrodes implanted in their brains, researchers have shown for the first time that areas of the brain work together at the same time to recall memories. The unique approach promises new insights into how we remember details of time and place.

Researchers at the University of Glasgow are hoping to help victims of stroke to overcome physical disabilities by helping their brains to ‘rewire’ themselves.

Keeping active can slow down the progression of memory loss in people with Alzheimer’s disease, a study has shown.

Neuroscientists have released the results of a new study that examines how fear responses are learned, controlled, and memorized. They show that a particular class of neurons in a subdivision of the amygdala plays an active role in these processes.

Neuroscience researchers from Tufts University have found that our star-shaped brain cells, called astrocytes, may be responsible for the rapid improvement in mood in depressed patients after acute sleep deprivation. This in vivo study, published in the current issue ofTranslational Psychiatry, identified how astrocytes regulate a neurotransmitter involved in sleep. The researchers report that the findings may help lead to the development of effective and fast-acting drugs to treat depression, particularly in psychiatric emergencies.

UC Berkeley neuroscientists have found that the slow brain waves generated during the deep, restorative sleep we typically experience in youth play a key role in transporting memories from the hippocampus – which provides short-term storage for memories – to the prefrontal cortex’s longer term “hard drive.”

Researchers have found altered connectivity in the brain network for body perception in people with anorexia: The weaker the connection, the greater the misjudgement of body shape.

A group of scientists planning to map all the major connections in the human brain began studying their first test subjects in August. The $30 million Human Connectome Project will trace the main neural pathways that link the roughly 500 major regions in the brain, illuminating how biological circuitry underlies our mental functions. MRI scans of 1,200 people, including 300 pairs of twins, will be used to compile an atlas of communication routes throughout the brain. The resulting blueprint will also reveal how brain connectivity varies from person to person.