| ObjectivesThe purpose of this study is to explore the similarities and differences of response inhibition and brain activation between Attention-deficit/hyperactivity disorder(ADHD)and normal children by neuropsychological tests and brain imaging techniques.Methods1.Children with ADHD(7-14 years old)diagnosed by DSM-V,was investigated by a set of measurement tools,the results of which were compared with normal developed children,matched by gender,age and educational level.Behavioral feature was also collected by parents reported questionnaires.2.Functional Magnetic Resonance Imaging(fMRI)scans were acquired under Go/NoGo task,using the SPM8 software to process the functional data.At the 1st-level,define two conditions: correct NoGo and correct Go trials.correct NoGo minus correct Go trials to get the contrast image for each subject.Then,at the 2nd-level,a random effects statistical model was used for group analysis,and the single-sample t-test was used to obtain the brain-activated image.The difference of brain activation between the two groups was analyzed by two-sample t-test.Results Part One Demographic and clinical characteristicsThere were no significant differences in age,sex and total IQ among the ADHD group and the control group.Compared with the control group,the ADHD group had significantly higher scores in PSQ,including conduct problems(t=5.114,P=0.000),learning problems(Z=-10.309,P=0.000),somatic factor(Z=-5.200,P=0.046),impulsivity hyperactivity(Z=-10.684,P=0.000),and hyperactivity index(Z=-11.549,P=0.000).while in anxiety score was no significant difference(t=0.865,p=0.394).Part Two Comparison of original scores of the neuropsychological test between the ADHD group and control groupThere were significant differences in sustained error number of WCST(t=2.668,P=0.012),correct number in test B of stroop test(t=-3.414,P=0.020)and response time of Go trail in Go/NoGo task(t=3.391,P=0.002)between the ADHD group and control group.Part Three fMRI Data 1.Within-Group AnalysisDuring successful Inhibition(NoGo>Go contrast),ADHD group have significantly increased activation in the inferior frontal gyrus,superior frontal gyrus,while decreased activation of area is in the left postcentral gyrus,posterior cingulate(left precuneus),medial frontal gyrus,cerebellum anterior lobe,left middle temporal gyrus.Control group in the inferior frontal gyrus(insula),precentral gyrus,frontal gyrus,cuneus(calcarine),right precuneus,inferior parietal lobule had obvious increased activation,while in the left postcentral gyrus,posterior cingulate(left precuneus),medial frontal gyrus,posterior lobe and left the thalamus significantly decreased activation.Regions with overlapping increased activation included: inferior frontal gyrus.Regions with overlapping decreased activation included: left postcentral gyrus,posterior cingulate gyrus(left precuneus),left medial frontal gyrus,cerebellum.2.Between-Group AnalysesADHD group had markedly greater activation of Left lingual gyrus and Right Rolandic Operculum during successful responses Inhibition than control group Conclusions1.Children with ADHD have the deficit of response inhibition,the difference of response inhibition is not obvious between ADHD and normal children in special situation,may be associated with the existence of compensatory mechanisms in children with ADHD.2.The inferior frontal gyrus is an important brain region involved in the process of response inhibition.3.The deficit of response inhibition in children with ADHD may be associated with abnormal default mode network.4.Children with ADHD showed greater activity in the left lingual gyrus,suggesting that increased visual cortex activation may be one of compensatory mechanism to make up for the deficit of its response inhibition. |
