Daydreaming Linked To ADHD Gene

Posted on: Monday, 22 November 2010, 07:56 CST

(Ivanhoe Newswire) -- A recent study finds a gene linked to attention deficit hyperactivity disorder (ADHD) leads to daydreaming.? Researchers believe these findings are the first to show ? through brain scanning ? the dissimilarities in the brain network relationships between individuals with this specific form of gene and others with a different form.

"Our goal is to narrow down the function of candidate genes associated with ADHD, and in this study, we find this gene is tied to competition between brain networks.? This could lead to increased inattention, but it likely has nothing to do with hyperactivity," which the study's lead author, Evan Gordon, a doctoral candidate in the interdisciplinary program in neuroscience at Georgetown University Medical Center, was quoted as saying.? "This is just one gene, and it does not cause ADHD but likely contributes to it. The disorder is believed to be due to a myriad of genetic factors."

DAT1 is the gene in question. Its protein produces the dopamine transporter that aids in regulating dopamine transmission between brain cells.? Furthermore, the DAT1 gene comes in two alleles (forms): DAT1 10 and DAT1 9.? Individuals who inherit two 10 alleles (10/10) are at greater risk for developing ADHD than those who inherit one of each allele (10/9).? Gordon adds that people rarely inherit two 9 alleles, and that the 10 allele is more frequent than the 9 allele.

The biological significance in regards to inheriting a DAT1 10 allele is that the brain produces excess quantities of dopamine transporters, which results in less dopamine signaling between neurons.? If too many dopamine transporters scoop up the dopamine released by those neurons, then fewer of them are able to actually reach other neurons and pass on a signal.? If there are fewer transporters, more dopamine stays in the synapse between neurons, resulting in a triggered reaction.

The dopamine is important for “gating” the transfer of information between brain regions ? allowing or preventing new information to come in.? "The belief is that dopamine helps teach certain brain regions how and when to gate, and that 10/10 carriers are not gating as quickly or effectively as is possible," Gordon said.?? That is exactly what the researchers discovered when they used functional MRI (fMRI) on 38 individuals who participated in the study.? Half of the groups were 10/10 carriers and half were 10/9 carriers; none of them were diagnosed with ADHD.

Researchers ultimately investigated the activity in two areas of the brain, the default mode network (DMN) ? associated with mind wondering or daydreaming ? and task-positive networks (TPNs) ? which are triggered and stay active during problem solving as well as other cognitive work.? In the study, participants were asked to remember letters they saw on a screen inside the fMRI machine, and to recall them, thus activating TPNs.

Scanning determined that in 10/10 carriers, the mind wandering areas tended to communicate with regions engaged in memory tasks much stronger than it did in 10/9 carriers.

"Dopamine in the 10/10 carriers was not doing a good enough job in preventing the mind wandering regions from interfering with memory performance regions, resulting in less efficient cognition," Gordon adds.

They also found no differences between genotype when the participants were at rest after their memory tasks.? "That tells us that the DAT1 genotype affects gating only when release of dopamine is high, such as during a memory task, and that less dopamine signaling leads to increased inattention," he concluded.

SOURCE: Annual Meeting of the Society for Neuroscience, November 2010

Source: Ivanhoe Newswire

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Gene Linked To ADHD Allows Memory Task To Be Interrupted By Brain Regions Tied To Daydreaming

Main Category: ADHD
Also Included In: Genetics;??Neurology / Neuroscience
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Neuroscientists at Georgetown University Medical Center (GUMC) say brain scans show that a gene nominally linked to attention deficit hyperactivity disorder (ADHD) leads to increased interference by brain regions associated with mind wandering during mental tasks.

Presented at the annual meeting of the Society for Neuroscience, these researchers believe their findings are the first to show, through brain scanning, the differences in brain network relationships between individuals with this particular form of gene and others with a different form.

"Our goal is to narrow down the function of candidate genes associated with ADHD, and in this study, we find this gene is tied to competition between brain networks. This could lead to increased inattention, but it likely has nothing to do with hyperactivity," says the study's lead author, Evan Gordon, a doctoral candidate in the Interdisciplinary Program in Neuroscience at GUMC. "This is just one gene, and it does not cause ADHD but likely contributes to it. The disorder is believed to be due to a myriad of genetic factors."

The gene in question is DAT1; its protein produces the dopamine transporter that helps regulate dopamine transmission between brain cells. The DAT1 gene comes in two alleles, or forms - DAT1 10 and DAT1 9. People who inherit two 10 alleles (10/10) are said to be at greater risk for developing ADHD than people who inherit 10/9 alleles. Rarely does someone inherit two 9 alleles, according to Gordon; he says, in fact, that the10 allele is slightly more common than the 9 allele.

The biological significance of inheriting a DAT1 10 allele is that the brain produces excess quantities of dopamine transporters, and that results in less dopamine signaling between neurons. Too many dopamine transporters quickly scoop up dopamine released by neurons, leaving fewer available to actually reach other neurons and pass on a signal. If there are fewer transporters, more dopamine stays in the synapse between neurons, triggering a reaction.

That is important, Gordon says, because dopamine is important for "gating" the transfer of information between brain regions - that is, allowing or preventing new information to come in. "The belief is that dopamine helps teach certain brain regions how and when to gate, and that 10/10 carriers are not gating as quickly or effectively as is possible."

That is exactly what the researchers found when they used functional MRI (fMRI) on a group of 38 participants. Half of the groups were 10/10 carriers and half were 10/9 carriers, and none of the participants were diagnosed with ADHD.

The researchers investigated the activity in two areas of the brain, the default mode network (DMN), which is associated with mind wandering or daydreaming and is active when the mind is at rest, and task-positive networks (TPNs), which are active during problem solving and other cognitive work. In this study, participants were asked to remember letters they saw on a screen inside the fMRI machine, and to recall them, thus activating TPNs.

Scanning demonstrated that in 10/10 carriers, the mind wandering areas tended to communicate with regions performing memory tasks more strongly than in did in 10/9 carriers. "Dopamine in the 10/10 carriers was not doing a good enough job in preventing the mind wandering regions from interfering with memory performance regions, resulting in less efficient cognition," Gordon says.

They also found no differences between genotype when the participants were at rest after their memory tasks.

"That tells us that the DAT1 genotype affects gating only when release of dopamine is high, such as during a memory task, and that less dopamine signaling leads to increased inattention," he says.

"Being a DAT1 10/10 carrier does not mean a person has ADHD; it is not a diagnostic marker," Gordon says. "It has been viewed as a contributing factor, and now we know one reason why."

The study was funded by the National Institute of Mental Health.

Source:
Karen Mallet
Georgetown University Medical Center

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Two Hours At TV Or Computer Screen Linked To Psychological Problems In Kids

Editor's Choice
Main Category: Pediatrics / Children's Health
Also Included In: Psychology / Psychiatry;??ADHD;??Mental Health
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A child who spends at least two hours a day in front of a TV screen or computer monitor has a significantly higher risk of developing psychological problems, no matter how much physical activity they do, researchers from the University of Bristol's Centre for Exercise, Nutrition and Health Sciences, England reported in an article published in the American Journal of Pediatrics. The more physically active children who were in front of a screen for at least two hours a day appeared to do better than their sedentary peers in emotional and peer problems, but fared worse in behavioral areas, including hyperactivity.

This latest study, called The PEACH project, assessed over 1,000 kids aged ten and eleven years. The investigators gathered data on how long they spent in front of a computer monitor and/or TV screen, as well as their mental health. The children's levels of physical activity were measured and recorded using an activity monitor.

The researchers found that those children who spend at least two hours watching TV and/or using their computer for non-homework use (recreational use) had higher psychological difficulty scores compared to their peers who spent less time in front of screens. The investigators add that the difficulty scores persisted, irrespective of how physically active the children were.

In other words, it appears that regular prolonged exposure to monitors/screens increases the risk of psychological problems, and exercise does not seem to get rid of the problem.

The authors believe that limiting a child's exposure to TV/Computer screens could play an important role in protecting their current and future mental health and well-being.

The activity monitor indicated that: Kids whose physical activity were gauged as sedentary appeared to get better overall psychological scores.Children with moderate physical activity seemed to have more behavior problems, including hyperactivity, but had better scores relating to peer problems and emotional issues.Their psychological well-being was evaluated via questionnaires which asked them to rate their strengths and difficulties in areas of hyperactivity, behavior (conduct), emotional, and peer problems. They read a series of statements and were asked to rate their truth value with a score of 1 to 3 - with 1 being untrue and 3 being certainly true. En example of statements they had to rate regarding emotional well-being included; "I am often unhappy, down-hearted or tearful', while statements to assess their peer problems included; 'I am usually on my own', 'I generally play alone or keep to myself."

Lead author, Angie Page said:

Whilst low levels of screen viewing may not be problematic, we cannot rely on physical activity to 'compensate' for long hours of screen viewing.

Watching TV or playing computer games for more than two hours a day is related to greater psychological difficulties irrespective of how active children are.

Source: University of Bristol's Centre for Exercise, Nutrition and Health Sciences

"Children's Screen Viewing is Related to Psychological Difficulties Irrespective of Physical Activity"
Angie Page et al
Published online October 11, 2010
PEDIATRICS (doi:10.1542/peds.2010-1154d)

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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posted by pj on 11 Oct 2010 at 5:46 am

It's wrong to conclude that screen usage causes psychological problems.

Results of statistical tests such as these cannot determine cause and effect. It could be that kids with psychological problems use screens for over 2 hours, or that a 3rd factor, perhaps low birth weight makes both increased screen usage and psychological problems occur.

The strongest language you can use is 'linked'. Which caused which cannot be determined.

So please stop sensationalizing the results of these types of experiments.

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posted by anonymous on 11 Oct 2010 at 5:58 am

If the issue is exposure to the screen itself, why does it matter whether computer usage is recreational or for homework?

Is there any trend toward higher correlations with specific types of screens? Would using an iPad to read eBooks instead of paper books cause the same issues? What if it was a Kindle, which emits no light of its own but rather uses ambient light?

If the message here is "Keep your kids away from the computer screen!", there are far greater implications as schools require more Internet research for homework and eBooks gain greater market share... assuming there isn't really some special exemption for homework use.

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posted by rob on 11 Oct 2010 at 6:15 am

These kinds of surveys are proven time and again to be very skewed and not enough information collated to give a absolute scientific answer. did all the children survey have exactly the same environment such as parents social wealth? Also the content of what is view I feel would have a great bearing such as discovery planet or grand theft auto! It gets my goat these headline quotes to scare parents today! If anyone has psychological it's mothers who take all this information in and stress the kids out by being dithering wrecks.

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posted by Dr Billy Levin on 12 Oct 2010 at 9:22 am

The authors are confused. Children with problems like ADHD will naturally gravitrate to the TV/computer because of their right brains talents. The author has put the cart before the horse. These right brain vision talented children have the ability to also have more emotional problems, not caused by the TV but as a genetically inherited condition.

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posted by evelyn haskins on 14 Oct 2010 at 10:44 pm

While I agree with previous posters re kids with psychological problems or potential for psychological problems (as Asperger's kids) are far more likely to use the computer for hours a day, I also know from bitter experience that with some children too long watching a TV screen makes them both lethargic and aggressive.

Known as "Zombie TV viewers" these kids seem to go into an hypnotised state, even though when asked later they seem to not even remember what they were watching. With my son, we found that IF we MADE him look away from the screen and talk to use during the commercials he seemed to be OK.

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posted by Catherine Doyle on 5 Nov 2010 at 8:09 am

Is it just me? It would seem this study also shows a relationship between physical activity and problems when it shows that sedentary children fared better psychologically than more active subjects as measured by the activity monitor. Maybe physical activity is the culprit. lol

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