ObjectiveTo investigate the difference of the spontaneous neuronal activity between attention-deficit hyperactivity disorder (ADHD) and normal children with amplitude of low-frequency fluctuation (ALFF) of the resting-state fMRI,and to discuss the correlation between the activity level of brain and symptom severity.MethodsThirty-two children with ADHD of school age and thirty age-and gender-matched controls were experienced with resting-state fMRI scans while blood oxygenation level dependent (BOLD) signal was acquired to calculate the amplitude of low-frequency fluctuation (ALFF).Linear correlations were performed between the aggregate score of RS-Ⅳ and ALFF voxels in ADHD patients.ResultsCompared to the controls,the ADHD group exhibited decreased ALFF in right superior frontal gyrus ( BA9,t =- 4.61 ),left superior medial frontal gyrus ( BA10,t =- 3.63 ),left mediate frontal ( BA46,t =- 4.09 ),and left anterior cingulate cortex ( BA24,t =- 4.02).Meanwhile,it showed increased ALFF in the medial orbitofrontal cortex( BA11,t =3.52 ),right cuneus gyrus ( t =3.93 ),right mediate occipital gyrus ( BA 19,t =3.82),right cerebellum ( BA37,t =3.77),right mediate temporal gyrus( BA37,t =3.76),and left paracentral lobe ( BA6,t =3.77 ).Altered ALFF in left superior medial frontal gyrus(P=0.009,r=0.492)and the right cuneus gyrus(P=0.024,r=0.433) showed correlation with the aggregate score of RS-Ⅳ.ConclusionThe spontaneous neuronal activity decreases in prefrontal cortex and increases in default mode network of ADHD group,the activity level of left prefrontal and right cuneus gyrus is positively correlated with symptom severity.