Nonetheless, reports of behavioral deficits in olfactory function and structural abnormalities in the olfactory system in schizophrenia offer limited insights into the relevant brain activity. Recent functional magnetic resonance imaging (fMRI) evidence in healthy adults suggests that odor identification, as opposed to smelling of nonidentified odors, is specifically associated with activity of entorhinal cortex and hippocampus (Kjelvik et al., 2012), but it remains to be seen whether these structures can be linked to smell identification deficits in schizophrenia. While functional imaging methods (e.g., PET, SPECT, fMRI) have shown decreased activation in schizophrenia in limbic as well as frontal and temporal regions in response to olfactory cues (e.g., Crespo-Facarro et al., 2001; Malaspina et al., 1998; Schneider et al., 2007), only electrophysiological correlates of information processing, with far greater temporal resolution, can provide direct, ‘real-time’ measures of olfactory function in schizophrenia and its risk states. Because event-related potentials (ERPs) trace the sequence of information processing by indexing neuronal activity, ERP components (e.g., N1, P2, P3), time-locked to the onset of sensory events, reflect brain activity representative of the underlying neurophysiologic processes
