The Brain Structure And Function Studies Of Schizophrenia In N-back Task

Part1:The alters of gray matter volumes at different stages of schizophreniaObjective To investigate the differences of gray matter volumes between first-episode (FES) and recurrently ill (REZ) patients with schizophrenia.Methods We examined structural brain changes in 28 first-episode and 27 recurrently ill patients with schizophrenia and 40 matched healthy control subjects by using voxel-based morphometry method. The whole structural differences between three groups were evaluated by using analysis of covariance (ANCOVA) model. The results were corrected by family-wise-error (FWE) method and then were used as ROIs. Then the Easy Volumes was used to measure the gray matter volumes of the ROIs.Results Compared to healthy control subjects, there were significant grey matter volumes reductions in schizophrenia patients, including anterior cingulate, bilateral medial prefrontal cortex, right rolandic operculum, right supramarginal gyrus and left middle frontal gyrus. This pattern was also exist in REZ patients, what is more, REZ patients showed extended alterations within right rolandic operculum and right supramarginal gyrus.Conclusions Progressive grey matter atrophy will also exist after the onset of the disease. We can also think that the pattern of the structural brain changes differs between different stages of disease, and the structural changes of default network is likely to be one of the pathophysiological mechanisms of schizophrenia.Part2:The alterations of cognition in adulthood patients with schizophrenia is correlated with gray mattersObjective To investigate the relationship between gray matters and cognition in adulthood patients with schizophrenia.Methods We collected 56 adulthood patients with schizophrenia and 56 matched healthy control subjects. All subjects were tested with digit span test and semantic fluency test, and their brains were scanned in mri. PANSS was used to evaluate the symptoms of schizophrenia. And then, voxel-based morphometry method was used to examine the structural brain differences between schizophrenia and healthy controls. The results were corrected by family-wise-error (FWE) method and then were used as ROIs. Then the Easy Volumes tool was used to measure the gray matter volumes of the ROIs. Finally, we used the correlation analysis to explore the correlations between the gray matters and cognition and the psychiatric symptoms.Results Compared to healthy control subjects, adulthood patients with schizophrenia had poor performances in digit span test and semantic fluency test, and the poor performances were not correlated with psychiatric symptoms. And there were significant grey matter volumes reductions in schizophrenia patients, including medial frontal gyrus, anterior cingutate, right middle frontal gyrus, right superior frontal gyrus, right insula, superior temporal gyrus and precentral gyrus. In addition, the gray matter volumes of them were correlated with digit span test and semantic fluency test.Conclusions There were significant grey matter volumes reductions and cognition impairments in adulthood patients with schizophrenia. And the cognition impairments were correlated with the gray matter volumes loss. Therefore, the loss of gray matter volumes in schizophrenia may be the structural basis of cognition impairments.Part 3:Brain activations as mediator of the relationship between the brain structure and numeric working memoryObjective To explore the mechanism of working memory impairments in schizophrenia.Methods We collected 70 health controls and 42 schizophrenic patients and compared the status of activations in numeric N-Back task and also measured the task performance and corresponding brain structure. Then a mediation analysis was conduct to test the relationship among brain structures, working memory and gray matter volume in healthy controls and schizophrenia.Results Compared to health controls, patients with schizophrenia showed poor working memory performance in 2-back task, and schizophrenia had reduced positive activation in SMA, left middle frontal gyrus, left precentral gyrus, left superior parietal lobule, left inferior parietal lobule and right cerebellum anterior lobe, cerebellum posterior lobe. For deactivation patterns, reduced negative activation was existed in bilateral middle cingulate, bilateral posterior cingulate, bilateral rectal gyrus, left inferior frontal gyrus, bilateral supplementary motor area, bilateral MPFC, and right supramarginal gyrus, inferior parietal lobule, precentral Gyrus. And overlapped brain areas of lower activations and atrophic gray matter volume in right supramarginal gyrus and bilateral MPFC were observed. There were no mediation effects of regional gray matter volumes of right supramarginal gyrus on numerical working memory, in spite of there were significant associations between the regional volume of right supramarginal gyrus and numerical working memory. On the contrary, the effects of regional MPFC volumes on numerical working memory is complete mediated by the functions of MPFC. And there were significant associations between the regional volume of MPFC and numerical working memory.Conclusion The loss of gray matter volumes in patients with schizophrenia are the structural basis of impaired working memory. And, different brain regions affected the cognitive function of patient in different ways. The loss of gray matter volume of MPFC would affect their own functional activities, and finally leads to the working memory impairments in schizophrenia.