Functional and structural brain markers of the genetic vulnerability to schizophrenia: A neuroimaging investigation of schizophrenia patients, non -psychotic adult relatives, and community ontrols

Diffuse functional and structural brain abnormalities are commonly found in schizophrenia patients and are reported in patients' first-degree non-psychotic relatives. Previously, investigators have reported functional and structural abnormalities in the prefrontal and parietal cortices of schizophrenia patients and non-psychotic relatives compared to controls. The goal of the present study was to recruit a new sample of schizophrenia patients, non-psychotic relatives, and community controls to investigate in tandem, functional and structural correlates of the schizophrenia diathesis at varying genetic loads. Imaging data were collected on 27 patients, 23 non-psychotic relatives, and 36 controls. Functional imaging was conducted during a context processing task that required the active suppression of an automatic tendency to complete a weaker task-relevant response. Analysis of behavioral data demonstrated all groups had more difficulty overriding an automatic response evidenced by longer mean reaction times on these trials compared to automatic response trials. Schizophrenia patients demonstrated more difficulty inhibiting automatic responses than completing an automatic response compared to relatives and controls. Schizophrenia patients and relatives demonstrated less activity than controls during maintenance of context-related information in the left inferior prefrontal region (BA 45/46). In addition structurally, schizophrenia patients demonstrated thinner superior frontal, inferior parietal, and supramarginal regions compared to controls and relatives. Impairments associated with the genetic vulnerability to schizophrenia in this sample were the greatest when neural correlates were taxed using a cognitive paradigm and measured directly using fMRI.