Anterior cingulate dysfunction during choice anticipation in schizophrenia.

The anterior cingulate cortex (ACGC) participates in selective attention, working memory (WM), anticipation, and behavioral monitoring. Subjects with schizophrenia exhibit deficits in these mechanisms during selective attention and WM tasks. However, ACGC dysfunctions have not been specifically investigated during behavioral anticipation, whose deficits may relate to salient schizophrenic features such as foresight abnormalities and impaired social functioning and behavior. We thus studied ACGC function in relation to two aspects of WM, remembering information and anticipating responses, in control and schizophrenic subjects. We measured brain activation in eight subjects with schizophrenia and eight healthy volunteers using functional magnetic resonance imaging. All subjects performed stimulus-response delay tasks with color dots or facial expression diagrams as cues and either 50% or 100% response predictability, which emphasized demands on remembering the cues or anticipating the response for correct performance, respectively. We found a double dissociation of ACGC activation between subject groups and task type. In controls, the ACGC became intensely activated during response anticipation (more extensively and bilaterally when the cues were colors than when they were facial diagrams) but remained at resting activity levels during remembering. In schizophrenic patients, significant ACGC activation was seen only when remembering a percept (more extensively and bilaterally when it was a facial diagram than when it was a color) but not when anticipating a response. These results reveal an ACGC dysfunction during choice anticipation in schizophrenia and suggest that it might underlie the foresight deficits seen in schizophrenic patients.