Abstract
Background. People with schizophrenia exhibit both visual thalamo-cortical hyperconnectivity and visual cortico-cortical hypoconnectivity (Damaraju et al., 2014; Anticevic et al., 2014), yet it remains unclear whether these two patterns occur equally in primary and secondary visual networks, whether they are specific to schizophrenia, and whether they are related to one another. Method. We addressed these questions by analyzing two independent data sets. In the first, we computed functional connectivity (FC) matrices from 36 people with schizophrenia (SZs), 40 people with bipolar disorder (BPs), and 93 healthy controls (HCs); in the second, we computed matrices from 15 SZs, 13 BPs, and 19 HCs. The primary and higher-order visual networks were defined via a recent brain network partition (Ji et al., 2019). Motion was controlled via scrubbing or spike regression; motion-prone subjects had already been removed (for Method details, see Hearne et al., 2021; Keane et al., 2022). FC was extracted from 718 regions (358 subcortical) via principal components multiple regression. Results. In each data set, in the secondary visual network , SZs exhibited thalamo-cortical hyperconnectivity (ps<.04, Hedges gs>.45) and cortico-cortical hypoconnectivity compared to HCs (ps<.02, Hedges g>.7). BPs exhibited connectivity patterns that were consistently intermediate between the remaining groups. No group differences emerged in the primary visual network. In the larger data set, after normalizing for each subject group and FC variable, a univariate ANOVA revealed that thalamo-cortical connectivity values were negatively associated with cortico-cortical connectivity values (p=.002), and that this relationship itself did not depend on subject group (p=.6). Discussion. Visual dysconnectivity characterizes the secondary visual network in schizophrenia, and to a lesser extent bipolar disorder, perhaps from a failure to regulate thalamic input into visual areas. The clinical and behavioral consequences of these connectivity patterns remain to be investigated.