Resting State Functional Magnetic Resonance Imaging Study Of Smoking In Schizophrenic Patients

PART ONE:USING REGIONAL HOMOGENEITY TO EXPLORE THE NEUROIMAGING MECHANISM OF SMOKING IN SCHIZOPHRENIC PATIENTSObjective: The mechanism of high smoking rate in schizophrenia patients is unclear.Resting-state is proved to be a useful technology in studying neurological and psychiatric disorders.Regional homogeneity(ReHo)might be an accessible tool to explore this issue.Methods: Using resting-state functional magnetic resonance imaging,Differences of ReHo were compared between smokers with schizophrenia and nonsmokers with schizophrenia groups,as well as between nonsmokers with schizophrenia and normal nonsmokers controls.Results: Compared to nonsmokers with schizophrenia,smokers with schizophrenia group showed significantly decreased ReHo in the left medial frontal gyrus,as well as increased reho in the left Cerebellum Posterior Lobe and Lingual Gyrus(p<0.001).In addition,ReHo in the left Cerebellum Posterior Lobe of smokers with schizophrenia pisitivelycorrelated with daily smoking count(r=0.635,p=0.027).Compared to normal nonsmokers controls,nonsmokers with schizophrenia group showed increased ReHo in the bilateral Medial Frontal Gyrus,right Temporal Lobe,left Cuneus and decreased ReHo in the right Anterior Cingulate,bilateral Postcentral,bilateral Thalamus.Conclusion:ReHo abnormalities in the left Cerebellum Posterior Lobe,left medial frontal gyrus and left lingual gyrus might be the possible neurological mechanism of schizophrenia patients with high smoking rates.PART TWO:USING AMPLITUDE OF LOW FREQUENCY FLUCTUATION TO EXPLORE THE NEUROIMAGING MECHANISM OF SMOKING IN SCHIZOPHRENIC PATIENTSObjective: The mechanism of high smoking rate in schizophrenia patients is unclear.Resting-state functional magnetic resonance imaging is proved to be a useful technology in studying neurological and psychiatric disorders.Amplitude of spontaneous low frequency fluctuation(ALFF)might be an accessible tool to explore this issue.Methods: Forty-two schizophrenia patients(21 smokers and 21nonsmokers)and 21 sex-and age-matched healthy nonsmokers underwent resting-state functional MRI.Whole brain internal brain activity was measured by the amplitude of spontaneous low frequency fluctuation.Furthermore,correlation analyses between z ALFF,symptom severity and nicotine addiction severity were performed.Results:ALFF values in prefrontal cortex,right caudate,and right postcentral gyrus were related to both schizophrenia and nicotine addiction degree.Compared to schizophrenia nonsmokers,schizophrenia smokers showed reversed internal brain activity in the above brain regions.In addition,compared to nonsmokers,schizophrenia smokers showed altered internal brain activity in the left striatal and motor cortices.The internal brain activity of the right caudate was negatively correlated with symptom severity.The internal brain activity of the right postcentral gyrus was negatively correlated with nicotine addiction severity.Conclusion:Smoking reversed internal brain activity in the right striatal and prefrontal cortices in schizophrenia,which is consistent with the self-medication theory in schizophrenia.Smoking altered left striatal and motor cortices activity,suggesting that the nicotine addiction effect was independent of disease.These results provide a local property of intrinsic brain activity mechanism that contributes to cigarette smoking and schizophrenia.