ADHD children make poor decisions due to less differentiated learning processes

Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most common psychiatric disorders among school children. Pupils with ADHD often make poorer decisions than their unaffected classmates.

Researchers from the University of Zurich now discovered that different learning and decision-making mechanisms are responsible for these behaviors, and localized the underlying impairments in the brain.

Which shirt do we put on in the morning? Do we drive to work or take the train? From which takeaway joint do we want to buy lunch?

We make hundreds of different decisions every day. Even if these often only have a minimal impact, it is extremely important for our long-term personal development to make decisions that are as optimal as possible.

People with ADHD often find this difficult, however. They are known to make impulsive decisions, often choosing options which bring a prompt but smaller reward instead of making a choice that yields a greater reward later on down the line.

Researchers from the University Clinics for Child and Adolescent Psychiatry, University of Zurich, now reveal that different decision-making processes are responsible for such suboptimal choices and that these take place in the middle of the frontal lobe.

Mathematical models help to understand the decision-making processes
In the study, the decision-making processes in 40 young people with and without ADHD were examined.

Lying in a functional magnetic resonance imaging (fMRI) scanner to record the brain activity, the participants played a game where they had to learn which of two images carried more frequent rewards.

To understand the impaired mechanisms of participants with ADHD better, learning algorithms which originally stemmed from the field of artificial intelligence were used to evaluate the data.

These mathematical models help to understand the precise learning and decision-making mechanisms better.

"We were able to demonstrate that young people with ADHD do not inherently have difficulties in learning new information; instead, they evidently use less differentiated learning patterns, which is presumably why sub-optimal decisions are often made", says first author Tobias Hauser.

Multimodal imaging affords glimpses inside the brain
To study the brain processes that triggered these impairments, the authors used multimodal imaging methods, where the participants were examined using a combined measurement of functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to record the electrical activity and the blood flow in the brain.

It became apparent that participants with ADHD exhibit an altered functioning in the medial prefrontal cortex, a region in the middle of the frontal lobe.

This part of the brain is heavily involved in decision-making processes, especially if you have to choose between several options, and in learning from errors.

Although a change in activity in this region was already discovered in other contexts for ADHD, the Zurich researchers were now also able to pinpoint the precise moment of this impairment, which already occurred less than half a second after a feedback, i.e. at a very early stage.

Psychologist Tobias Hauser, who is now researching at the Wellcome Trust Centre for Neuroimaging, University College London, is convinced that the results fundamentally improve our understanding of the mechanisms of impaired decision-making behaviour in people with ADHD.

The next step will be to study the brain messenger substances. "If our findings are confirmed, they will provide key clues as to how we might be able to design therapeutic interventions in future," explains Hauser.

More information: Tobias U. Hauser, Reto Iannaccone, Juliane Ball, Christoph Mathys, Daniel Brandeis, Susanne Walitza & Silvia Brem: Role of Medial Prefrontal "Cortex in Impaired Decision Making in Juvenile Attention-Deficit/Hyperactivity Disorder," in: JAMA Psychiatry, DOI: 10.1001/jamapsychiatry.2014.1093

Dyslexia, less brain tissue not to blame for reading difficulties

It has previously been suggested that people with dyslexia have less gray matter in the brain and this has been  reportedly linked to reading disabilities.

Thankfully this ridiculous notion has been debunked.

New evidence suggests that the amount of brain material in people with dyslexia may be a result and consequence of their poorer reading experiences and not the root cause of the disorder.

It has been assumed that the difference in the amount of gray matter might, in part, explain why dyslexic children have difficulties correctly and fluently mapping the sounds in words to their written counterparts during reading but this assumption of causality has now been rightly turned on its head.

Guinevere Eden

The findings from anatomical brain studies conducted at Georgetown University Medical Center (GUMC) in the Center for the Study of Learning led by neuroscientist Guinevere Eden, DPhil, were published online today in The Journal of Neuroscience.

The study compared a group of dyslexic children with two different control groups: an age-matched group included in most previous studies, and a group of younger children who were matched at the same reading level as the children with dyslexia.

"This kind of approach allows us to control for both age as well as reading experience," explains Eden, a professor of pediatrics at GUMC.

"If the differences in brain anatomy in dyslexia were seen in comparison with both control groups, it would have suggested that reduced gray matter reflects an underlying cause of the reading deficit. But that's not what we observed."

The dyslexic groups showed less gray matter compared with a control group matched by age, consistent with previous findings.

However, the result was not replicated when a control group matched by reading level was used as the comparison group with the dyslexics.

Anthony Krafnick

"This suggests that the anatomical differences reported in left hemisphere language processing regions appear to be a consequence of reading experience as opposed to a cause of dyslexia," says Anthony Krafnick, PhD, lead author of the publication.

"These results have an impact on how we interpret the previous anatomical literature on dyslexia and it suggests the use of anatomical MRI would not be a suitable way to identify children with dyslexia," he says.

The work also helps to determine the fine line between experience-induced changes in the brain and differences that are the cause of cognitive impairment.

For example, it is known from studies in illiterate people who attain reading skills as adults that this type of learning induces growth of brain matter.

Similar learning-induced changes in typical readers may result in discrepancies between them and their dyslexic peers, who have not enjoyed the same reading experiences and thus have not undergone similar changes in brain structure.

Your Opinion Required: Firstborn children are 25% less trusting and reciprocating

Popular (mis)conceptions say that 'First-born children are more likely to achieve greatness', but recent research claims that if this is true, then it comes at a price. Scientists say that the only-child and the first-born child is more likely to be less trusting, and have a less generous or a less cooperative disposition.

Previous Research
Previous studies would lead us to believe that firstborns are generally smarter than their younger siblings and perhaps more likely to become leaders, while younger brood-members tend to be more rebellious. It would be interesting to know if you have found this to be proven, in the real world.

Recent Research
To see if trust in adults might also be affected by birth order, Alexandre Courtiol at the Institute of Evolutionary Sciences in Montpellier, France, paired 510 students with anonymous partners to play a finance-based game.

It is a standard game used to shows a umber of things:

• the level of trust a person has in other people,
  
• their willingness to take part in collaborative and cooperative behaviour and
  
• the level of risk they are willing to take.

It can also be used to try and understand the level of 'greed' a person has but that's a much more intangible trait that needs other coroborating data.

The Rules of the Game
Both players were given 30 monetary units and told that whatever they had left at the end of the game would be converted into real cash. Player A was told to give any sum of money to player B, with the knowledge that this would be tripled for player B's pot. Player B then had the option of giving any sum of money back to player A.

The Results
The selfish decision would have been for neither player to give any money away, but less than 1 in 10 participants played this way. The more money player A gave away, the more trusting they were judged to be and the more money player B tended to return, showing reciprocity.

Summary
On average, an only-child or the eldest of a number of sibling, gave 25 per cent less "money" than non-firstborns or only children, whether they were in role A or B. Courtiol interprets this as meaning firstborns were 25 per cent less trusting and reciprocating (Animal Behaviour, DOI: 10.1016/j.anbehav.2009.09.016).