Differences in bi-stable perception across three paradigms in people with schizophrenia

People with schizophrenia (SZ) experience psychotic symptoms that include hallucinations and distorted perception of real stimuli. Bi-stabile perception occurs when the same physical stimulus yields two alternating percepts that compete for dominance. Previous work from our group and others has demonstrated abnormal bi-stable switch rates in SZ compared to healthy controls. Surprisingly, differences in bi-stable switch rates between groups may vary across bi-stable paradigms. Previous reports have found slower switch rates during binocular rivalry (BR) in SZ, whereas we have recently found faster switch rates during a bi-stable structure-from-motion (SFM) paradigm. In an ongoing study, we examined bi-stable switch rates using three different paradigms: BR, SFM (i.e., the rotating cylinder), and biological motion (BM; i.e., ambiguous point-light-walker), in 23 SZ participants and 16 healthy controls. Preliminary results suggest a trend toward faster switch rates among SZ participants vs. healthy controls during the BM task. For SFM, switch rates were also numerically higher on average in SZ vs. controls, but this difference was not significant. However, during the BR task there was a trend for slower switch rates in SZ vs. healthy controls, consistent with results in the literature. Additionally, we did not see significant differences in bi-stable switch rates among people with bipolar disorder (19) vs. controls. Our results suggest that atypical perception of bi-stable stimuli in SZ may not be uniform across paradigms. Switch rates appeared slower in paradigms involving inter-ocular suppression (i.e., BR), whereas bi-stable motion paradigms tended to evoke faster switch rates in SZ, which may indicate multiple abnormalities in SZ at distinct levels of visual processing.