P3 (Polich, 2007). In such a three-stimulus oddball task (Friedman et al., 1993), novelty P3 and P3b can be readily distinguished by their topographic differences (mid-frontocentral vs. mid-parietal maximum) and condition dependencies. Although a novelty oddball paradigm has previously been employed in schizophrenia using ERP (e.g., Mathalon et al., 2010) or functional magnetic resonance imaging (fMRI) measures (e.g., Laurens et al., 2005), with the former study failing to observe differential deficits of P3a and P3b and the latter suggesting that patients less efficiently divide processing resources between detecting and responding to the task-relevant target tones and reorienting and ignoring task-irrelevant novel sounds, to our knowledge, there are no such studies involving CHR patients.
