OBJECTIVETo compare resting-state functional magnetic resonance imaging (fMRI) findings of children with attention-deficit hyperactivity disorder (ADHD) and normal children, and to investigate the possible mechanism of brain dysfunction in children with ADHD.

METHODSResting-state fMRI was performed on 18 children who met the DSM-IV diagnostic criteria for ADHD (ADHD group) and 18 normal children (control group) matched for age, sex, IQ, degree of education and handedness. The two groups were compared in terms of amplitude of low frequency fluctuation (ALFF) and regional homogeneity (ReHo).

RESULTSCompared with the control group, the ADHD group had decreased ALFF in the bilateral posterior lobes of the cerebellum and the left side of the pons, increased ALFF in the right precentral gyrus, decreased ReHo in the left medial frontal gyrus, right superior frontal gyrus, and left precuneus, and increased ReHo in the left anterior lobe of the cerebellum, left caudate nucleus, right parahippocampal gyrus, left precentral gyrus, and right middle frontal gyrus.

CONCLUSIONSIn resting state, children with ADHD have decreased brain activity in some regions, including the cerebellum and frontal cortex, compared with normal children, which supports the hypothesis of dysfunctional fronto-cerebellar circuits in ADHD.