SA69. Neural Basis of Trust Deficits in Schizophrenia: An fMRI Investigation

摘要

>Background: Trust and reciprocity are an integral part of human social interactions. One of the characteristic features of schizophrenia, paranoid delusions, indicates an underlying lack of trust in other human beings. However, only a few studies have examined the neural basis of trust deficits in schizophrenia using fMRI. >Methods: Fourteen patients with schizophrenia (age: 33.50 + 6.01, education: 14.86 + 1.83) and 14 healthy controls (age: 24.39 + 3.79, education: 16.64 ± 2.82) participated in the study. Participants underwent an fMRI scan while engaged in a modified version of trust game. Participants played the role of investors and were told that in 12 trials they would interact with a human counterpart (trustee) while in the other 12 trials they would invest in a lottery. Each participant was endowed with INR 12 in each trial. In each trial, participants had the option of keeping all the money to himself or herself or investing/sharing a part of it (INR 4, 8, or 12). The images were preprocessed and analyzed using SPM 12. Images were corrected for motion and time of acquisition, coregistered to the respective structural images, segmented, normalized, and smoothed. The contrasts comparing decision phases of human and lottery trials were modeled at the individual subject level. For the second-level analysis, the first-level contrasts were entered into a 2-sample t-test to compare patient and healthy control groups. The results were thresholded at P < .001 (uncorrected) and a cluster threshold of 15 voxels. >Results: Compared to controls, patients had significantly lesser activations in right anterior and posterior cingulate gyri (BA 24 and 32), right superior and middle frontal gyri (BA 6, 9, and 10), superior temporal gyrus (BA 38 and 22), right supramarginal gyrus (BA 40), and striate cortex (BA 17). On the other hand, they showed increased activation in posterior cingulate (BA 23). >Conclusion: The results indicate that patients with schizophrenia process situations involving trust differently from healthy controls. Superior frontal cortex especially ventromedial regions have been consistently implicated in attribution of intentions and mentalizing. The lower activation in patients suggest aberrant neural processing which would result in less trusting behavior. If replicated in a larger sample, these preliminary findings would help us to better understand the neural basis of trust deficits in schizophrenia.