Neural Substrates of Inhibitory Control Deficits in 22q11.2 Deletion Syndrome.

[22q11.2 deletion syndrome]

22 q 11 .2 deletion syndrome (22 q 11 DS ) is associated with elevated levels of impulsivity , inattention , and distractibility , which may be related to underlying neurobiological dysfunction due to haploinsufficiency for genes involved in dopaminergic neurotransmission (i .e . catechol-O-methyltransferase ). The Stop-signal task has been employed to probe the neural circuitry involved in response inhibition (RI ); findings in healthy individuals indicate that a fronto-basal ganglia network underlies successful inhibition of a prepotent motor response . However , little is known about the neurobiological substrates of RI difficulties in 22 q 11 DS . Here , we investigated this using functional magnetic resonance imaging while 45 adult participants (15 22 q 11 DS patients , 30 matched controls ) performed the Stop-signal task . Healthy controls showed significantly greater activation than 22 q 11 DS patients within frontal cortical and basal ganglia regions during successful RI , whereas 22 q 11 DS patients did not show increased neural activity relative to controls in any regions . Using the Barratt Impulsivity Scale , we also investigated whether neural dysfunction during RI was associated with cognitive impulsivity in 22 q 11 DS patients . RI -related activity within left middle frontal gyrus and basal ganglia was associated with severity of self-reported cognitive impulsivity . These results suggest reduced engagement of RI -related brain regions in 22 q 11 DS patients , which may be relevant to characteristic behavioral manifestations of the disorder .