Increased global cognition correlates with increased thalamo-temporal connectivity in response to targeted cognitive training for recent onset schizophrenia

Abstract

Patients with schizophrenia exhibit disrupted thalamocortical connections that relate to aspects of symptoms and deficits in cognition. Targeted cognitive training (TCT) of the auditory system in schizophrenia has been shown to improve cognition, but its impact on thalamocortical connectivity is not known. Here we examined thalamocortical connections that may be neuroplastic in response to TCT using a region of interest (ROI) approach. Participants were randomly assigned to either 40 h of TCT (N = 24) or an active control condition (CG; N = 20). Participants underwent resting state fMRI and cognitive testing both before and after training. Changes in thalamocortical connectivity were measured in 15 ROIs derived from a previous study comparing a large sample of schizophrenia subjects with healthy controls. A significant group by time interaction was observed in a left superior temporal ROI which was previously found to exhibit thalamocortical hyper-connectivity in patients with schizophrenia. Changes in this ROI reflected thalamic connectivity increases in the TCT group, while the CG group showed decreases. Additionally, the relationship between connectivity change and change in global cognition showed a slope difference between groups, with increases in thalamo-temporal connectivity correlating with improvements in global cognition in TCT. No significant relationships were observed with changes in clinical symptoms or functioning. These findings demonstrate that TCT may influence intrinsic functional connections in young individuals with schizophrenia, such that improvements in cognition correspond to compensatory increases in connectivity in a temporal region previously shown to exhibit thalamic hyper-connectivity.

Keywords: Cognition; Cognitive training; Connectivity; Schizophrenia; Thalamus.

Figure 1

Note: (A) Region of the left superior temporal gyrus (STG; Z=10) found to show a group × time interaction in response to TCT versus CG. (B) Significant group × time interaction (F=12.12; p=.0008) characterized by increased connectivity in the TCT group, and decreased connectivity in the CG group. (C) Slopes difference between groups correlating change in connectivity and change in global cognition (t=2.85; p=.007), characterized by a positive correlation in the TCT group (r=.50; p=.02), and a non-significant negative correlation in the CG group (r=−.34; p=.14).