Study On Resting - State Magnetic Resonance Of Forced Obstruction

Objective:Obsessive-compulsive disorder(OCD) is a chronic psychiatric disorder typically associated with recurrent thoughts and repetitive behaviors. Patients experience substantial distress and impairment within daily life, social and occupational settings for the early onset age and high incidence. The prevailing models of OCD pathophysiology have focused on cortex-striatal-thalamus-cortex circuitry. However, more recent neuroimaging evidence points to some other brain areas as the pathophysiology of the disorder, in addition to the CSTC circuitry. Magnetic Resonance Imaging technology had been used to investigate the further sub-circuitries formatted the recent model of OCD pathophysiology from structural and functional areas.Methods:Patients were admitted from the outpatients in Nanjing Brain Hospital Affiliated to Nanjing Medical University during October 2011 to October 2014, and healthy control subjects were recruited during the same time. The Yale-Brown Obsessive Compulsive Scale(Y-BOCS), Hamilton Rating Scale for Depression 17-Item(HAMD-17) and Hamilton Anxiety Rating Scale(HAMA) were used to assess the clinical symptoms. All of the participants were scanned with magnetic resonance imaging(MRI) for grey matter volume, regional homogeneity, amplitude of low frequency fluctuation, fractional amplitude of low frequency fluctuation, and functional connectivity by using SPM8, VBM8, DPARSF, REST and AFNI software tools. Independent-samples T test was used to compare the changes between the OCD patients and the healthy controls. Pearson’s correlation analysis, partial correlation analysis or linear regression analysis was used to analysis the relationship between the changes of structure or function. Overlapping the aforementioned results might create the valid result that show significantly correlation with the scale score.Results:1) All of the 68 OCD patients were separated to four dimensions: unacceptable mind(21, 30.9%), checking(18, 26.5%), washing(17, 25%), ordering(7, 10.3%), and two participants were mixed symptom. 2) As compared with the controls, the studied patients with OCD showed significantly reduced gray matter volume(GMV) in the left calcarine, left precuneus and right cingulate gyrus(P<0.05). Significant positive correlation was observed between the decreased volume in left calcarine and total Y-BOCS scores(r=0.380, P=0.009). 3) Compared with the controls, the patients showed higher Re Ho in the left prefrontal lobe, and lower in the left occipitotemporal regions and bilateral fusiform gyrus. But no significant correlation was found between the different areas and the clinical symptom score. 4) Compared with the controls, the patients showed lower ALFF in the left prefrontal lobe, but no f ALFF changing. 5) Compared with the controls, the patients showed significant reduce grey matter volume in bilateral orbitalfrontal cortex(OFC), cingulate gyrus, olfactory, insula, thalamus, caudate, middle temporal gyrus, central gyrus and right parietal lobe, angular gyrus and left precuneus(P<0.05). There was significant positive correlation between the changes of grey matter volume in left middle occipital gyrus and the HAMD-17 scores or HAMA scores.6) The overlap of the changes of grey matter volume and the correlational brain areas were right lingual gyrus in checking dimension subjects, that show positive correlation between the GMV and the Y-BOC scales, and right mid cingulate gyrus in unacceptable dimension subjects, that show negative correlation between the GMV and the HAMD scales. 7) Compared with the controls, the patients showed increased functional connectivity in temporal lobe and occipital lobe when cingulate gyrus was set as seed. Active connectivity was shown in right parietal lobe and mid cingulate gyrus, and reduced connectivity was shown in right cingulate gyrus, left parietal lobe and right precuneus when orbitalfrontal cortex(OFC) was set as seed. Caudate-related functional network had shown reduced connectivity in right cingulate gyrus, left precuneus, left insula, left putamen and right inferior parietal lobe. Precuneus-related functional network had shown active connectivity in bilateral temporal lobe, right frontal lobe and left precuneus, and reduced connectivity in left frontal lobe, right superior parietal cortex and right cerebellum.Conclusion:1) The pathophysiology models of OCD are cortex-striatal-thalamus-cortex(CSTC) circuitry and some other areas beyond the CSTC circuitry. 2) The cortex-striatal-thalamus-cortex circuitry and the other areas beyond the CSTC circuitry are formed by the complex structural and functional sub-circuitries, the heterogeneity of OCD and the multi-dimension of symptom.