Weekly Neuroscience Update

UCL Medical staff discussing an image of a human brain

Researchers at University College London have made a breakthrough in the way that drugs could be delivered to the brain, tackling the difficult problem of constructing drugs which are able to pass through the blood-brain barrier – a mechanism which prevents many chemicals in the bloodstream from passing into the brain, including synthetic compounds administered as medication as well as harmful environmental toxins.

For older adults looking to sharpen their mental abilities, it might be time to log on to Facebook. Preliminary research findings from the University of Arizona suggest that men and women older than 65 who learn to use Facebook could see a boost in cognitive function.

A single concussion may cause lasting structural damage to the brain, according to a new study published online in the journal Radiology.

In an effort to better evaluate and prevent concussions and head traumas, researchers at Johns Hopkins University have developed a computer model to identify what types of jarring movements to the body can cause injury to the brain

A team of sleep researchers has confirmed the mechanism that enables the brain to consolidate memory and found that a commonly prescribed sleep aid enhances the process. Those discoveries could lead to new sleep therapies that will improve memory for aging adults and those with dementia, Alzheimer’s and schizophrenia.

How do neurons store information about past events? In the Nencki Institute of Experimental Biology of the Polish Academy of Sciences in Warsaw, a previously unknown mechanism of memory trace formation has been discovered. It appears that at least some events are remembered thanks to geometry.

It is possible to tell who a person is thinking about by analyzing images of his or her brain. Our mental models of people produce unique patterns of brain activation, which can be detected using advanced imaging techniques according to a study by Cornell University neuroscientist Nathan Spreng and his colleagues.

Columbia University Medical Center (CUMC) researchers have found the first evidence that selective activation of the dentate gyrus, a portion of the hippocampus, can reduce anxiety without affecting learning.

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

 

 

Understanding ADHD and Learning Disability Part V: Diagnosing ADHD

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

Diagnosing ADHD – it’s harder than you think.

Currently there is no diagnostic test for ADHD. Diagnosis requires a clinical interview, parent and teacher ratings for children, and self and other ratings for adults. In addition, it is estimated that two-thirds of children diagnosed with ADHD have additional learning disorders or other mental health or neurodevelopmental conditions.   This makes it all the more important that the diagnosis is made in a multi-disciplinary environment, where the child or adult is assessed by a medical doctor, counsellor, clinical psychologist and if necessary by a psychiatrist. This is important because problems with attention can be triggered by many other conditions; in particular, adults may have attention issues along with other disorders such as depression.

….and there’s more…

Other factors have been found to affect diagnosis of ADHD. For example, the youngest children in a class are much more likely to be diagnosed as having ADHD compared to their older counterparts in the same year. This is because these children may behave more hyperactively, not because they have ADHD, but because they are younger and developmentally behind their classmates. In fact, it is estimated that about 20% of children given a diagnosis of ADHD are misdiagnosed because of the month they were born with children born in December (the youngest in class) 39% more likely to be diagnosed with ADHD than those born in January (the oldest in class).

Journal reference: http://www.ncbi.nlm.nih.gov/pubmed/22392937

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

 

 

 

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

 

Understanding ADHD and Learning Disability

Attention deficit/hyperactivity disorder (ADHD)and the learning disability which often accompanies it came up in conversation with students on the Family Support Course during my recent visit to the Bedford Row Family Project in Limerick. There was concern that ADHD was not being accurately diagnosed and that its treatment was inadequate at best.

In this first in a series of posts on ADHD Professor David Anderson explains how the current medical understanding of ADHD as merely a chemical imbalance in the levels of the two neurotransmitters dopamine and noradrenaline is not working and shows that by investigating a strain of hyperactive fruit fly (Drosophila), ADHD and learning disability involve two separate nerve pathways in the brain. These new findings may help scientists discover more selective treatments for these surprisingly commonplace disorders.

If you suffer from ADHD and/or a learning disability then this video may help you connect your personal experience with what the scientists are now discovering

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

Weekly Neuroscience Update

A run of poor sleep can have a potentially profound effect on the internal workings of the human body, say UK researchers.

As a bird sings, some neurons in its brain prepare to make the next sounds while others are synchronized with the current notes—a coordination of physical actions and brain activity that is needed to produce complex movements, new research at the University of Chicago shows. In an article in the current issue of Nature, neuroscientist Daniel Margoliash and colleagues show, for the first time, how the brain is organized to govern skilled performance—a finding that may lead to new ways of understanding human speech production.

Deep brain stimulation has helped people with severe obsessive-compulsive disorder, and new research begins to explain why. A Dutch study appearing in the Feb. 24 online issue of the journal Nature Neuroscience found the procedure essentially restored normal function in a part of the brain called the nucleus accumbens.

Researchers have identified a possible treatment window of several years for plaques in the brain that are thought to cause memory loss in diseases such as Alzheimer’s. The Mayo Clinic study is published in the Feb. 27 online issue of Neurology.

Though it’s most often associated with disorders like diabetes, Harvard researchers have shown how the signaling pathway of insulin and insulin-like peptides plays another critical role in the body – helping to regulate learning and memory.

Researchers in Scotland and Germany have discovered a molecular mechanism that shows promise for developing a cure for Huntington’s Disease (HD).

Some people do not learn from their mistakes because of the way their brain works, according to research led by an academic at Goldsmiths, University of London. The research examined what it is about the brain that defines someone as a ‘good learner’ from those who do not learn from their mistakes.

Scientists from the University of Oxford say they have discovered how the brain protects itself from damage that occurs in stroke.

A team of French researchers has discovered that the human brain is capable of distinguishing between different types of syllables as early as three months prior to full term birth. 

The Art of the Brain

Hippocampus

Greg Dunn  swapped the life of a scientist for that of artist when he finished his Ph.D. in neuroscience at Penn in 2011.

Cerebellum – a region of the brain important for movement, balance, and motor memory

He has sold commissioned works to research labs and hospitals, and he says his prints are popular with neuroscientists, neurologists, and others with a special interest in the brain, including people with neurodegenerative disorders.

Developing cortex

This painting shows the developing human cerebral cortex, at about week 15 of gestation.