Impaired updating of working memory in schizophrenia.

This study investigated working memory in schizophrenia, using an auditory target detection task specifically designed to separate out brain activity related to the updating of working memory with new information from activity related to target detection and response. Event related potentials (ERPs) were recorded during task performance, using 31 electrodes, from 25 subjects with schizophrenia and 25 matched controls. Subjects with schizophrenia had a reduction in parietal P3 and Late Slow Wave amplitude in the ERP waveforms recorded when the task required subjects to remember a new stimulus. This P3 amplitude attenuation correlated with symptom measures of preoccupation and poor volition. Previous findings of a reduction in P3 amplitude during target detection by subjects with schizophrenia were replicated. These results suggest that there is a specific impairment in the ability to update working memory in schizophrenia, and that this is associated with poverty of engagement with the environment.