Psychosis risk is associated with decreased white matter integrity in limbic network corticostriatal tracts

It is thought that altered connectivity between the striatum and the cortex could contribute to psychosis. However, whether psychosis risk is associated with altered white matter connectivity between the striatum and any cortical region is still unclear. Further, no previous study has directly examined whether psychosis risk is associated with altered striatal connectivity with specific cortical networks. The current study examined the integrity of corticostriatal white matter tracts in psychosis risk (n=18) and in non-psychosis risk comparison participants (n=19). We used probabilistic tractography to identify white matter tracts connecting each of four different striatal subregions with their most functionally connected cortical network: limbic, default mode, frontoparietal, and motor networks. We then compared groups on fractional anisotropy in these four tracts. Psychosis risk was associated with decreased fractional anisotropy in white matter tracts connecting the limbic striatum with the limbic cortical network, especially in an anterior right external capsule segment and in tracts specifically connected to the right prefrontal cortex. In contrast, psychosis risk was not associated with decreased white matter integrity in other corticostriatal tracts. Hence, the current research suggests that psychosis risk is especially associated with decreased corticostriatal white matter integrity involved in processing emotional and personally relevant information.