Hippocampal Resting State Functional Connectivity in Patients With Schizophrenia and Unaffected Family Members.

E Kale Edmiston,Ke Xu,Miao Chang,Qian Zhou,Yanzhuo Song,Zhiyang Yin,Fei Wang,Yanqing Tang,Yifang Zhou,Xiaowei Jiang,Shengnan Wei

doi:10.3389/fpsyt.2020.00278

Abstract

The hippocampus is an important candidate region in the study of functional connectivity alterations in schizophrenia (SZ) given its role as a functional hub for multiple brain networks. Although studies have implicated the hippocampus in SZ, no studies have compared hippocampal functional connectivity in healthy participants, patients with SZ, and unaffected family members (UAFMs). Patients and UAFM likely share biomarkers associated with susceptibility to SZ; the study of UAFM may also reveal compensatory markers. Patients with SZ, UAFM, and healthy control (HC) participants underwent resting state magnetic resonance imagingty and completed the Wisconsin Card Sort Task (WCST) as a measure of general cognitive function. We compared functional coupling with a hippocampus seed across the three groups. SZ and UAFM groups shared reductions in connectivity between the hippocampus and the striatum relative to HC. We also identified a significant positive correlation between WCST errors and hippocampal-striatal connectivity in the UAFM group. Hippocampal-striatal rsFC may be associated with familial susceptibility to SZ and with subtle cognitive deficits in the UAFM of individuals with SZ.

Highlights

Schizophrenia (SZ) is a highly heritable psychiatric disorder characterized by disruptions in multiple cognitive domains, including attention, associative learning, and set shifting[1]
Comparison of patients relative to unaffected family members (UAFMs) and healthy control (HC) could elucidate functional network alterations specific to illness onset, illness susceptibility, as well as compensatory factors
For neuroimaging findings in data preprocessed without global signal regression, we examined correlations between the hippocampus and regions identified in the original analyses

Summary

Introduction

Schizophrenia (SZ) is a highly heritable psychiatric disorder characterized by disruptions in multiple cognitive domains, including attention, associative learning, and set shifting[1]. These deficits are often present in the unaffected family members (UAFMs) of patients with SZ and are likely due to shared alterations in brain functional networks [2]. Others have shown that hippocampal functional deficits predict transition to psychosis in at-risk subjects [7] While this literature implicates the hippocampus in the pathophysiology of SZ, it is unclear if functional deficits are related to susceptibility or conversion to psychosis. It could be that alterations in hippocampal functional networks underlie the cognitive impairment that is observed in both at-risk cohorts and patients with SZ, i.e., that hippocampal alterations are a matter of degree and not of kind

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Conclusion