Auditory and Visual Thalamocortical Connectivity Alterations in Unmedicated People With Schizophrenia: An...

Converging evidence from clinical neuroimaging and animal models has strongly implicated dysfunction of thalamocortical circuits in the pathophysiology of schizophrenia (SZ). Preclinical models of genetic risk for SZ have shown reduced synaptic transmission from the auditory thalamus to the primary auditory cortex, which may represent a correlate of auditory disturbances such as hallucinations. However, human neuroimaging studies have found a generalized increase in resting-state functional connectivity (RSFC) between whole thalamus and sensorimotor cortex in people with SZ (PSZ). We aimed to more directly translate preclinical findings by specifically localizing auditory and visual thalamic nuclei in unmedicated PSZ and measuring RSFC to primary sensory cortices.

In this case-control study, 82 unmedicated PSZ and 55 matched healthy control participants (HCs) completed RSFC functional magnetic resonance imaging (fMRI) (N = 137). Auditory and visual thalamic nuclei were localized for 55 unmedicated PSZ and 46 HCs who also completed a sensory thalamic nuclei localizer fMRI task (n = 101). Using localized nuclei as RSFC seeds, we assessed group differences in auditory and visual thalamocortical connectivity and associations with positive symptom severity.

Auditory thalamocortical connectivity was not significantly different between PSZ and HCs, but hyperconnectivity was associated with greater positive symptom severity in the bilateral superior temporal gyrus. Visual thalamocortical connectivity was significantly greater in PSZ relative to HCs in the secondary and higher-order visual cortex but was not predictive of positive symptom severity.

These results indicate that visual thalamocortical hyperconnectivity is a generalized marker of SZ, while hyperconnectivity in auditory thalamocortical circuits relates more specifically to positive symptom severity.