these two groups is that PFC lesion patients have normal ERN amplitudes, whereas schizophrenia patients have smaller ERN amplitudes. During errors of commission, schizophrenic patients had a decreased hemodynamic response in the ACC (Carter, MacDonald, Ross, & Stenger, 2001) and more specifically in the rostral ACC (Laurens, Ngan, Bates, Kiehl, & Liddle, 2003). Additionally, studies suggest that schizophrenia is also characterized by decreased structure and function of the ACC (Zetzsche et al., 2007). Future studies should investigate both the ERN and the CRN in schizophrenia to determine whether changes in both of these components represent a general inability of individuals with schizophrenia to self-monitor. It is of interest to note that there is an abundant literature on the P300 component in schizophrenia which suggests that deficits in attention may impact task performance and related psychophysiological measures (see Ford, 1999 for a review). Thus, ERN findings may result from a more general deficit found in schizophrenia rather than being specific to response monitoring.
