Weekly Neuroscience Update

 

 

smellsensiti.jpg

Credit: Herz et. al./Brown University

new study provides the first direct evidence that within each person, smell sensitivity varies over the course of each day. The pattern, according to the data, tracks with the body’s internal day-night cycle, or circadian rhythm.

Researchers have revealed the neural signatures for explicit and implicit learning.

Neuroscientists have discovered precisely where and how to electrically stimulate the human brain to enhance people’s recollection of distinct memories. People with epilepsy who received low-current electrical pulses showed a significant improvement in their ability to recognize specific faces and ignore similar ones.

Adults likely do not develop ADHD, according to new research.

Researchers propose a new theory of memory formation, reporting memory storage does not rely on the strengthening of connection between memory cells, but on the pattern of connections that form within the first few minutes of an event.

A new Finnish study shows that individual circadian preference is associated with brain activity patterns during the night.

According to researchers, the size, shape and number of dendritic spines in the brain may determine whether a person develops Alzheimer’s disease.

Finally this week, migraine triggers can increase oxidative stress, a new study reports. Targeting oxidative stress may help to prevent migraines.

 

 

Weekly Neuroscience Update

By using a novel technique to test brain waves, researchers are discovering how the brain processes external stimuli that do and don’t reach our awareness. Credit Beckman Institute.

By using a novel technique to test brain waves, researchers are discovering how the brain processes external stimuli that do and don’t reach our awareness. Credit Beckman Institute.

Researchers at the Beckman Institute are using a novel technique to test brain waves to see how the brain processes external stimuli that do and don’t reach our awareness. A group of international scientists has for the first time identified genetic mutations that suggest that schizophrenia and autism share underlying mechanisms. The research could help with future understanding of both conditions and may contribute to the development of treatments. Two psychologists have made a discovery that could revolutionize doctors’ perception and treatment of attention-deficit disorders. A newly identified disorder affecting the human nervous system is caused by a mutation in a gene never before implicated in human disease, according to two studies published in the journal Cell. By performing DNA sequencing of children affected by neurological problems, two research teams independently discovered that a disease marked by reduced brain size, as well as sensory and motor defects, is caused by a mutation in a gene called CLP1. Insights into this rare disorder may have important implications for the treatment of common disorders.

Scientists at the Salk Institute have created a new model of memory that explains how neurons retain select memories a few hours after an event. This new framework provides a more complete picture of how memory works, which can inform research into disorders liked Parkinson’s, Alzheimer’s, post-traumatic stress and learning disabilities.

Stanford scientists have developed faster, more energy-efficient microchips based on the human brain – 9,000 times faster and using significantly less power than a typical PC. This offers greater possibilities for advances in robotics and a new way of understanding the brain. For instance, a chip as fast and efficient as the human brain could drive prosthetic limbs with the speed and complexity of our own actions.

Finally this week, laughter triggers brain waves similar to those associated with meditation, according to a small new studyThe study included 31 people whose brain waves were monitored while they watched humorous, spiritual or distressing video clips. While watching the humorous videos, the volunteers’ brains had high levels of gamma waves, which are the same ones produced during meditation, researchers found.

 

Understanding ADHD and Learning Disability Part VIII

‘ADHD is an attention difference not an attention disorder.’

This inspiring video reinforces the view that we as a society must embrace cognitive diversity.

 

Related Reading

Part 1: Understanding ADHD and Learning Disability

Part 2: Understanding ADHD and Learning Disability

Part 3: Understanding ADHD and Learning Disability

Part 4: Understanding ADHD and Learning Disability

Part 5: Understanding ADHD and Learning Disability

Part 6: Understanding ADHD and Learning Disability

Part 7: Understanding ADHD and Learning Disability

 

Top ten blog posts of 2013

Top-10-ListThese were the most popular blog posts on Inside the Brain ranked according to most page views in 2013.

Does Addiction Exist?

What is ‘attention’ and where is it in the brain?

Understanding ADHD and Learning Disability

Understanding ADHD and Learning Disability Part V: Diagnosing ADHD

Could there an evolutionary advantage in having ADHD?

What can mirror neurons teach us about consciousness, mental health and well-being?

Inside The Musical Brain

This Is Your Brain On Poetry

Why Parkinson’s Disease Has Robbed Linda Ronstadt Of Her Singing Voice

How Did Tolerance Kill Cory Monteith?

Understanding ADHD and Learning Disability Part VII

In this final part of my series on understanding Attention Deficit/Hyperactivity Disorder (ADHD),  we delve more into the underlying mechanisms of the disorder.

Hyperactive flies can help us understand ADHD and learning disability.

Many researchers are seeking a better understanding of ADHD and the medications used to treat it by studying ADHD’s underlying mechanisms and working towards a better knowledge of this disorder.  In this video Professor David Anderson explains how our current understanding of ADHD (and the learning disability which can accompany it) as merely chemical imbalances in dopamine and noradrenaline is not working and shows that by studying a strain of hyperactive fruit fly (Drosophila) we can study the different nerve pathways involved in ADHD and learning disability which will help in providing safer and more effective treatments.

Small cold-water fish

There is no cure for ADHD at this time. However a recent (2012) study in the Journal of the American Medical Association  reports that fish consumption during pregnancy protects against ADHD in the child. In addition, many ADHD sufferers also report a beneficial effect of daily fish oil. If you are considering including fish in your diet then the study recommends small cold-water fish such as herring, mackerel, sardines and salmon rather than larger fish such as tuna which live much longer and thereby may accumulate the toxic metal mercury.

Further reading for those interested in the scientific experiments:

  1. Lebestky et al. (2009). Neuron, 64 (4), 522-36 PMID: 19945394
  2. Wang L, & Anderson DJ (2010). Nature, 463 (7278), 227-31 PMID: 19966787

Other Sources:

http://www.brainfacts.org/Diseases-Disorders/Childhood-Disorders/Articles/2012/Confronting-Attention-Deficit-Hyperactivity-Disorder

Related Reading

Part 1: Understanding ADHD and Learning Disability

Part 2: Understanding ADHD and Learning Disability

Part 3: Understanding ADHD and Learning Disability

Part 4: Understanding ADHD and Learning Disability

Part 5: Understanding ADHD and Learning Disability

Part 6: Understanding ADHD and Learning Disability

 

 

Understanding ADHD and Learning Disability Part VI: How is ADHD treated?

This is the sixth in a series on understanding Attention Deficit/Hyperactivity Disorder (ADHD).

Treatment

ADHD is commonly treated with parent education, school-based interventions, and medications such as stimulants (e.g., methylphenidate) and newer, nonstimulant drugs such as atomoxetine. Adults benefit from the same medications as children and may find some behavioural therapies helpful. On the behavioral side, children can be taught strategies for staying focused on a task such as following a detailed schedule, or for organizing materials. Adult ADHD can be a family problem as well as an individual problem. Because the symptoms of the disorder often wreak havoc on every member of the family, not just the individual with adult ADHD, it’s important for the entire group to undergo family therapy, even if the ADHD parent is already getting individual counselling. It is best to begin family therapy as soon as it becomes clear that the symptoms of adult ADHD are interfering with normal family functioning and thus avoid crises and emergencies that may take months or years to resolve. Family therapy may include teaching family members new skills and coping strategies, and therapy in which family members support and encourage each other and learn to communicate more effectively.

Drug treatment of ADHD

Many children with ADHD may also need medication. The use of stimulants to treat ADHD was first described in 1937.Since the late 1960s, stimulants such as Ritalin® or Adderall® have been prescribed to treat children with ADHD.

2011-12 shortage in U.S. market

In 2011 and 2012, there was a shortage of Ritalin® and Adderall® in U.S. pharmacies. Some say the shortage was caused by the US Drug Enforcement Administration’s (DEA) annual limits on the manufacture of controlled substances. The DEA argues that drug manufacturers had caused the shortage by applying their quotas toward more lucrative kinds of amphetamine-based medications. The shortage was resolved by November 2012. Currently, between 4 and 6 million children in the United States take one of these medications, which reduce hyperactivity and impulsivity, help improve the ability to focus, and even improve physical coordination. In fact, medications are so effective in helping people with ADHD that a recent shortage wreaked havoc for many families

Drug action

Nonetheless, there is concern about giving children a drug that is potentially addictive. Methylphenidate, the active ingredients in Ritalin®, acts like a weak form of cocaine to increase dopamine and noradrenaline levels but tend to do it all over the brain sometimes resulting in unwanted side-effects such as nervousness, drowsiness, insomnia, suspicion and paranoia. Concerta®is a slow release of methylphenidate while Daytranta® delivers the drug via a skin patch, similar to those used for nicotine replacement therapy.Adderall® is a mixture of amphetamine salts which also increase dopamine and noradrenaline levels but has a higher potential for abuse than Ritalin®.

Controversy

In addition, there is a worry that ADHD may be over-diagnosed, leading to the diagnosis and treatment of high-energy children who have difficulty in the classroom, but are medically normal. For this reason the effectiveness of treatments should be re-evaluated in each person on a regular basis to determine if the current treatment continues to be optimal. There are some reports that daily intake of fish oil can be helpful.

Related Reading

Part 1: Understanding ADHD and Learning Disability

Part 2: Understanding ADHD and Learning Disability

Part 3: Understanding ADHD and Learning Disability

Part 4: Understanding ADHD and Learning Disability

Part 5: Understanding ADHD and Learning Disability

 

 

Could there an evolutionary advantage in having ADHD?

Ariaal Elder

Ariaal Elder. The Ariaal are northern Kenyan pastoralists.

This is the fourth in a series on understanding Attention Deficit/Hyperactivity Disorder (ADHD). Today I want to examine if there is in fact an evolutionary advantage in having ADHD.

ADHD is strongly genetic and the genes involved regulate the levels of two neurotransmitters called dopamine and noradrenaline (noradrenaline is called norepinephrine in North America) – chemicals which act as messengers between nerve cells.

Hyperactivity has long been part of the human condition and some ADHD – linked genes are more common in nomadic populations and those with more of a history of migration. In fact,the health status of nomadic men such as those from the Ariaal people in northern Kenya was higher if they had an ADHD – linked gene. However, recently settled Ariaal men seemed to have slightly worse health.

ADHD – ‘the don’t fence me in’ gene

In nomadic Ariaal society,  those with ADHD may be better in tasks involving risk, competition, and/or unpredictable behavior (i.e. exploring new areas, finding new food sources, etc.). For instance, an Ariaal person killing a lion is highly respected and in these situations, ADHD would have been beneficial to the society as a whole even while severely detrimental to the individual.In addition, women in general are more attracted to males who are risk takers, thereby promoting ADHD in the gene pool. This might help explain why ADHD-linked genes have survived to the present day but are more suited to a previous nomadic, risk-taking lifestyle.

Like mother – like son

More recent research suggests that because ADHD is more common in mothers who are anxious or stressed that ADHD is a mechanism of priming the child with the necessary traits for a stressful or dangerous environment, such as increased impulsivity and explorative behaviour etc.

Journal reference: BMC Evolutionary Biology (DOI: 10.1186/1471-2148-8-173)

Part 1: Understanding ADHD and Learning Disability

Part 2: Understanding ADHD and Learning Disability

Part 3: Understanding ADHD and Learning Disability

 

 

 

Weekly Neuroscience Update

mgr_correl_all_wparavol

Composite of the scans of 20 individuals. Regions in yellow and red are linked to the parietal lobe of the brain’s right hemisphere.

Scientists say they have published the most detailed brain scans “the world has ever seen” as part of a project to understand how the organ works.

Psychologists at the University of Amsterdam (UvA) have discovered that changes in patterns of brain activity during fearful experiences predict whether a long-term fear memory is formed.

New findings about how the brain functions to suppress pain have been published in the leading journal in the field Pain, by National University of Ireland Galway (NUI Galway) researchers. For the first time, it has been shown that suppression of pain during times of fear involves complex interplay between marijuana-like chemicals and other neurotransmitters in a brain region called the amygdala.

Some of the dramatic differences seen among patients with schizophrenia may be explained by a single gene that regulates a group of other schizophrenia risk genes. These findings appear in a new imaging-genetics study from the Centre for Addiction and Mental Health (CAMH).

Research published in the March 2013 journal GENETICS explains a novel interaction between aging and how neurons dispose of unwanted proteins and why this impacts the rising prevalence of dementia with advancing age.

The brain adds new cells during puberty to help navigate the complex social world of adulthood, two Michigan State University neuroscientists report in the current issue of the Proceedings of the National Academy of Sciences.

The first large, population-based study to follow children with attention-deficit hyperactivity disorder into adulthood shows that ADHD often doesn’t go away and that children with ADHD are more likely to have other psychiatric disorders as adults. They also appear more likely to commit suicide and to be incarcerated as adults.

The infant brain does not control its blood flow in the same way as the adult brain, researchers have discovered.

Hypnosis has begun to attract renewed interest from neuroscientists interested in using hypnotic suggestion to test predictions about normal cognitive functioning. To demonstrate the future potential of this growing field, guest editors Professor Peter Halligan from the School of Psychology at Cardiff University and David A. Oakley of University College London, brought together leading researchers from cognitive neuroscience and hypnosis to contribute to this month’s special issue of the international journal, Cortex.

What is ‘attention’ and where is it in the brain?

This is the third in a series on Understanding Attention Deficit/Hyperactivity Disorder (ADHD). Today we look closer at the nature of attentiveness and its location in the brain.

english_brainAttention is the ability of the brain to selectively concentrate on one aspect of the environment while ignoring other things. There are two types of attention in two separate regions of the brain. The prefrontal cortex (directly behind the forehead) is in charge of willful concentration; if you are studying for a test or writing a novel, the impetus and the orders come from there. But if there is a sudden, riveting event – the attack of a tiger or the scream of a child – it is the parietal cortex (behind the ear) that is activated. Scientists have learned that these two brain regions sustain concentration when the neurons emit pulses of electricity at specific rates – faster frequencies for the automatic processing of the parietal region, slower frequencies for the deliberate, intentional work of the prefrontal region.

ADHD medications increase activity in the prefrontal cortex and attention-related areas of the parietal cortex during challenging mental tasks; these are the same areas that the study I cited yesterday demonstrated to be underactive in ADHD brains. However, there may be different forms of ADHD and there is an urgent need to develop more effective drugs to regulate these two different frequencies in order to improve attention for specific forms of the disorder.

Part 1: Understanding ADHD and Learning Disability

Part 2: Understanding ADHD and Learning Disability

Understanding Attention Deficit/Hyperactivity Disorder (ADHD) Part 2

In part two of my latest series on attention deficit/hyperactivity disorder (ADHD) we take a closer look at the nature of the disorder.

These positron emission tomography (PET) scans show that patients with ADHD had lower levels of dopamine transporters in the nucleus accumbens, a part of the brain’s reward center, than control subjects.

What is attention deficit/hyperactivity disorder?

Do you remember a classmate who just could not sit still or another who just sat quietly in the corner, day dreaming and looking out the window but when called on by the teacher did not know what was going on? Today both of these children might be diagnosed with ADHD. Indeed some still argue that there is no such thing as ADHD – that it is an artificially conceived diagnosis to aid the selling of prescription drugs and that in previous times a child with ‘ADHD’ was no more than considered to be no more than ‘bored’,’ restless’ or ‘giddy’.

Prognosis

ADHD was first described more than 100 years ago and its symptoms include excessively inattentive, hyperactive, or impulsive behaviours. For instance, children with ADHD find it more difficult to focus and to complete their schoolwork. ADHD affects up to eight in one hundred children and in over half the cases, it continues to persist into adulthood.Although most individuals with ADHD do not outgrow the disorder, their symptoms often change as they grow older, with less hyperactivity as adults. Problems with attention tend to continue into adulthood. There is no cure for ADHD at this time.

Possible causes

Recent brain imaging studies have shown a reduction in the levels of the neurotransmitters dopamine and noradrenaline in at least some people with the disorder. Because the nerve circuits in the prefrontal brain regions, which are normally involved in attention, require high levels of dopamine and noradrenaline stimulation, reduced levels of these two neurotransmitters could potentially lead to the weakened regulation of attention and behavior observed in ADHD .Altered brain activity also has been observed in particular nerve circuits connecting the cortex (outer part), striatum (deeper parts), and cerebellum (back of the neck), particularly in the right brain hemisphere with a delay in cortical development seen in some children with ADHD.
In part three of this series,  I will explain more what neuroscientists mean by ‘attention’, where it is found in the brain and how it is affected in ADHD.

Other Sources:
http://www.webmd.com/add-adhd/guide/

Part 1: Understanding ADHD and Learning Disability