ADHD Research Today is a free monthly online journal that collates and summarizes the latest research about ADHD, including details on attention-deficit hyperactivity disorder, drugs, treatment, symptoms. | ||||||||
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The cognitive neuroscience of response inhibition: relevance for genetic research in attention-deficit/hyperactivity disorder.Aron AR, Poldrack RA Department of Psychology and Brain Research Institute, University of California, Los Angeles, California 90095, USA. adamaron@ucla.edu Psychological functions that are behaviorally and neurally well specified may serve as endophenotypes for attention-deficit/hyperactivity disorder (ADHD) research. Such endophenotypes, which lie between genes and symptoms, may relate more directly to relevant genetic variability than does the clinical ADHD syndrome itself. Here we review evidence in favor of response inhibition as an endophenotype for ADHD research. We show that response inhibition--operationalized by Go/NoGo or Stop-signal tasks--requires the prefrontal cortex (PFC), in particular the right inferior frontal cortex (IFC); that patients with ADHD have significant response inhibition deficits and show altered functional activation and gray matter volumes in right IFC; and that a number of studies indicate that response inhibition performance is heritable. Additionally, we review evidence concerning the role of the basal ganglia in response inhibition, as well as the role of neuromodulatory systems. All things considered, a combined right IFC structure/function/response inhibition phenotype is a particularly good candidate for future heritability and association studies. Moreover, a dissection of response inhibition into more basic components such as rule maintenance, vigilance, and target detection may provide yet better targets for association with genes for neuromodulation and brain development. Published 13 June 2005 in Biol Psychiatry, 57(11): 1285-92.
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