Prefrontal functional dissociation in the semantic network of patients with schizophrenia

We examined whether deficient prefrontal control over the semantic network exists in patients with schizophrenia. Fourteen patients with schizophrenia and 14 healthy controls performed a comparison task, judging semantic congruity according to an abstract category in an event-related functional MRI paradigm. In the control group, prefrontal-temporal networks consisting of the left inferior frontal gyrus and right inferior frontal sulcus converging at the left posterior superior temporal sulcus were identified as activated during semantic demand of incongruence. In the patients with schizophrenia, we observed a loss of the recruitment of the right inferior frontal sulcus and the prefrontal-temporal network. These findings indicate that cognitive modulation of semantic processing may be dysfunctional in patients with schizophrenia.