Distinct inter-hemispheric dysconnectivity in schizophrenia patients with and without auditory verbal hallucinations

Abstract

Evidence from behavioral, electrophysiological and diffusion-weighted imaging studies suggest that schizophrenia patients suffer from deficiencies in bilateral brain communication, and this disruption may be related to the occurrence of auditory verbal hallucinations (AVH). To increase our understanding of aberrant inter-hemispheric communication in relation to AVH, we recruited two groups of first-episode schizophrenia patients: one group with AVH (N = 18 AVH patients) and one without hallucinations (N = 18 Non-AVH patients), and 20 healthy controls. All participants received T1 structural imaging and resting-state fMRI scanning. We adopted a newly developed index, voxel-mirrored homotopic connectivity (VMHC), to quantitatively describe bilateral functional connectivity. The whole-brain VMHC measure was compared among the three groups and correlation analyses were conducted between symptomology scores and neurological measures. Our findings suggest all patients shared abnormalities in parahippocampus and striatum. Aberrant bilateral connectivity of default mode network (DMN), inferior frontal gyrus and cerebellum only showed in AVH patients, whereas aberrances in superior temporal gyrus and precentral gyrus were specific to Non-AVH patients. Meanwhile, inter-hemispheric connectivity of DMN correlated with patients’ symptomatology scores. This study corroborates that schizophrenia is characterized by inter-hemispheric dysconnectivity, and suggests the localization of such abnormalities may be crucial to whether auditory verbal hallucinations develop.

Aberrant connectivity in auditory precision encoding in schizophrenia spectrum disorder and across the continuum of psychotic-like experiences

“…The SZS group showed reduced connectivity in lateral connections from left to right IFG and from right to left A1 as compared to the NP patient group suggesting that such reductions are specific to schizophrenia spectrum disorders. This is in line with previous results as it is robustly found that schizophrenia is associated with an interhemispheric disconnection 36–39 . Previous results on functional connectivity have shown that interhemispheric connectivity can distinguish schizophrenia patients from patients with depression, indicating specificity for schizophrenia 40 .…”

Early- and late-latency gamma auditory steady-state response in schizophrenia during closed eyes: Does hallucination status matter?

“…Taking into account the more impaired sensory gating (i.e. inability to filter out irrelevant stimuli) in patients with a history of hallucination (Smith et al, 2013;Smucny et al, 2013) and differences in the connectivity of the DMN between AVH and NH subjects (Kindler et al, 2015;Chang et al, 2015), it is possible that eyes closure might have an effect in NH group but not in AVH group. Our results thus suggest that the hyperexcitability in AVH was not modified by general subjects' state.…”

Reduction of Interhemispheric Functional Connectivity in Sensorimotor and Visual Information Processing Pathways in Schizophrenia

“…[ 21 ] Chang et al . [ 22 ] reported that the altered VMHC in the default mode network, inferior frontal gyrus, and cerebellum was associated with auditory hallucination symptoms, and aberrant VMHC in the sensorimotor region has been found only in schizophrenia patients experiencing nonauditory hallucination.…”