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What have we learned about ADHD from the functional imaging studies?

Małgorzata Dąbkowska

Affiliacja i adres do korespondencji
PSYCHIATR. PSYCHOL. KLIN. 2010, 10 (3), p. 195-199
Streszczenie

Functional imaging techniques provide information about metabolic activity and neural signalling in populations of neurons. Brain activation in ADHD has been assessed using a variety of techniques. The studies have been conducted in resting subjects and under varying conditions of cognitive stress. The aim of this article is to review the neuroimaging literature in ADHD, mainly in functional magnetic resonance imaging, positron emission tomography and single photon emission tomography. Through the use of various functional imaging techniques in conjunction with behavioural data and lesion studies we are now able to learn not only about the function of a brain region, but also about the use of covert behavioural and cognitive strategies. The impaired flexibility in recruiting brain regions and associated strategies limit adaptation to new cognitive demands as they present and may require more effort in processing. This article presents findings suggesting that ADHD should be characterized not only by neural hypoactivity, but neural hyperactivity as well, in regions of the brain that may relate to compensatory brain and behavioural functioning. The frontostriatal dysfunction may be central to the pathophysiology of ADHD, but there is now substantial evidence of functional alterations in regions outside the frontostriatal circuitry in ADHD, most notably in the cerebellum and the parietal lobes. More research is needed to elucidate the nature of contributions of nonfrontostriatal regions to the pathophysiology of ADHD.

Słowa kluczowe
attention-deficit/hyperactivity disorder, functional imaging, brain, children, physiopathology, cognitive strategies, functional connectivity