Event related brain potential evidence for preserved attentional set switching in schizophrenia.

Pervasive deficits of attention and set switching have been reported in schizophrenia, prompting efforts to identify the information processing mechanisms associated with these deficits. Recent evidence suggests that set switching may be intact in schizophrenia when the task switch requires only a change in the relevance of perceptual dimensions (e.g., attentional set switches) but decision-to-response mappings (intentional set) are maintained across trials in a cued task switching procedure. The goal of the present research was to replicate this finding and to test its direct corollary, which is the unconventional prediction that individuals with schizophrenia will evidence an intact, switch-sensitive P3(b) brain response to cued switches of attentional set. This prediction was tested in a group of 20 individuals with schizophrenia and 20 healthy comparison participants using event-related brain potential methodology and a cued task-switching task. Attentional set switching costs were equivalent between the two groups despite a set maintenance deficit in schizophrenia. Moreover, a posterior-parietal P3(b) component of the ERP was found to be equally sensitive to attentional set switching in schizophrenia and comparison groups, indicating a "healthy" brain response to switches of attentional set in schizophrenia. These results suggest that the dynamic control of attentional set may be preserved in schizophrenia and that previously reported executive deficits may be specific to the control of intentional task set and to deficits of task set maintenance.