Brain connectivity in patients with schizophrenia related to psychological stress

Abstract

Introduction It is commonly accepted that in most patients with schizophrenia external factors act on genetic predisposition to pro- duce active psychotic symptoms. In fact, we showed that patients with schizophrenia have an abnormal brain activation and per- ipheral autonomic response to psychological stress. We sought to characterize the brain connectivity networks of such response in schizophrenia.Methods We studied the pattern of brain connectivity in rela- tion to mental arithmetic stress paradigm in 21 patients and 21 healthy subjects aged 18 to 50 years, using 3T-fMRI. A period of 6minutes of resting state acquisition (PRE) were followed by a block design with three 1-minute CONTROL task (one digit sum), 1- minute STRESS task (two digit subtraction) and 1-minute rest after task (POST). Pairwise Pearson correlations were calculated between 90 regions of interest. Data were analyzed with MATLAB and SPSS software.Results Patients with schizophrenia showed a lower connec- tivity network between fronto-temporal limbic areas compared with control subjects during control and stress task. Moreover, we observed a great variability of link density during resting state in patients but not in controls, and it diminishes in response to task.Conclusions Patients present abnormalities in networks rela- ted to stress response showing an alteration in fronto-temporal connectivity, and a poor and random modulation of these net- works at rest. Current and previous findings suggest abnormal fronto-temporal connectivity that ultimately would lead to psycho- tic symptoms emergency in response to an environmental stressor and, even, could be related to hypervigilance and misattribution feeding into the paranoid cognition characteristic of patients with schizophrenia.