K. Rubia et al., Hypofrontality in attention deficit hyperactivity disorder during higher-order motor control: A study with functional MRI, AM J PSYCHI, 156(6), 1999, pp. 891-896
Objective: Functional magnetic resonance imaging (MRI) was used to investig
ate the hypothesis that attention deficit hyperactivity disorder (ADHD) is
associated with a dysfunction of prefrontal brain regions during motor resp
onse inhibition and motor timing. Method: Generic brain activation of seven
adolescent boys with ADHD was compared to that of nine comparison subjects
equivalent in sex, age, and IQ while they were performing a stop task, req
uiring inhibition of a planned motor response, and a motor timing task, req
uiring timing of a motor response to a sensory cue. Results: The hyperactiv
e adolescents showed lower power of response in the right mesial prefrontal
cortex during both tasks and in the right inferior prefrontal cortex and l
eft caudate during the stop task. Conclusions: ADHD is associated with subn
ormal activation of the prefrontal systems responsible for higher-order mot
or control. Functional MRI is a feasible technique for investigation of neu
ral correlates of ADHD.