Hyperactivity: Genetic and Neurological Aspects

If the environment promotes attention deficit hyperactivity, this disorder also has a genetic basis and meets certain neurobiological mechanisms.

The share of genes

Twin and adoption studies show that ADHD has a genetic base strong.

An estimated 75% heritability of hyperactivity (that is, 75% of the differences between free subjects and patients from their genetic differences).

Several candidate genes are explored. They probably Act interact, each explaining to him only a small part of the observed variance. These genes relate to the production, transport and the capture of dopamine and other neurotransmitters in the nervous system (D2/D3, SLC6A4, 5-HT2A, 5-HT1B, DAT1, DRD4, etc.).

Some researchers observed high prevalences in contemporary populations of hunter-gatherers have suggested that hyperactivity was most common in the early stages of human evolution, because it presented Adaptive advantages. Genes would be transmitted up to modern times, where social life is less compatible with the hyperactive tendencies.

In the hyperactive brain

Functional magnetic resonance imaging allows the doctor and the researcher to observe the functioning of the brain of patients.

This brain imaging shows that certain cortical areas of hyperactive children are less glucose mobilizing and are therefore less effective. The lateral prefrontal cortex and anterior dorsal Cingulate cortex are the two most often weakened areas. They are involved in the ability to lead and control his impulses to plan actions.

Neuromolecular perspective, a malfunction of the transport networks of dopamine, linking the neocortex base nuclei and the cerebellum, was highlighted in many patients.

Dopamine is a substance naturally produced by the brain. It is associated with disorders, mood and behaviour, but the motor (as in Parkinson's disease).