Abstract
A growing body of evidences suggests that the comparison of expected and incoming sensory stimuli (predictive error (PE) processing) is impaired in schizophrenia (SZ). For example in studies of mismatch negativity, an ERP component that signals PE, SZ patients show deficits in both the auditory (Fulham et al., 2014) and the visual (Neuhaus, Brandt, Goldberg, Bates, & Malhotra, 2013) modality. In order to test the role of impaired PE processing in SZ further, using neuroimaging methods, we applied a repetition suppression (RS) paradigm (Summerfield, Trittschuh, Monti, Mesulam, & Egner, 2008). 17 patients diagnosed with SZ according to DSM-IV-R / DSM V as well as 17 age and gender matched healthy control (HC) subjects were presented with pairs of faces which could either repeat or alternate. Additionally, the likelihood of repetition/alternation trials was modulated in individual blocks of fMRI recordings, testing the effects of repetition probability (P(rep)) on RS. We found a significant RS in the fusiform and occipital face areas, as well as in the lateral occipital cortex that was similar in both groups. More importantly, we observed similar P(rep) effects (significant RS in blocks with high repetition likelihood but not in blocks with low repetition likelihood) in both groups as well. Crucially, this suggests normal predictive processes in patients with Schizophrenia.
Meeting abstract presented at VSS 2015