Brain, Dopamine And ADHD

There are no confirmed causes of ADHD but it seems that ADHD runs in families, e.g. if your parent has ADHD, you have 10-25% chance of having it too. This suggests presence of a genetic component that impacts the structure and functioning of brain, e.g. how certain circuits are wired, the chemicals they use and how they use those chemicals.

Specifically, in an ADHD brain the default mode network and task related networks are correlated which means they get activated at the same time. This is a problem because they are kind of opposite things. The default mode network should be on when we do nothing and task related networks should be active when we do stuff. Thus, if they are on at the same time, they get into each others way.

Since dopamine regulates which networks should be active, it looks that there is something about the dopamine system in an ADHD brain that stops the networks from anti-correlating. That something seems to be a reduced transmission of dopamine between neurons due to malfunctioning dopamine transporters and receptors in particular circuits in the prefrontal brain. This then leads to low levels of dopamine which causes unnecessary firing of neurons that are not related to the task one is trying to do or the information one is trying to focus on. Thus, increasing the dopamine levels (e.g. via medication, a lot of coffee or smoking) helps networks anti-correlate and improve symptoms of ADHD.

Reference

One response to “Brain, Dopamine And ADHD”

  1. […] brings us back to the role of dopamine in the brain. Dopamine not only regulates anti-correlation of the default mode network and task related networks, but when it is released, it turns on the brain areas that narrow our visual and auditory […]

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