Auditory and visual hysteresis: common and modality-specific neural mechanisms
Tue—Casino_1.801—Poster2—5304
Presented by: Tim Redepenning
Bistable stimuli have often been used to study how our brain creates a stable perception or detects changes in the surrounding world. When the immediate perceptual past causes us to persist in a former percept and thus helps to stabilize our perception, this is termed hysteresis. We investigated the neural correlates underlying auditory and visual hysteresis. To this end, we recorded EEG data while presenting participants with ambiguous Necker cubes (Experiment 1) and Shepard tones (Experiment 2) in gradually shifted sequences to evoke a hysteresis effect. The behavioural data showed this effect for both modalities (p<.05). The subsequent ITC analysis revealed significant differences between the perception of stimuli in sequential order (hysteresis condition) and in random order. While we found modality-exclusive differences, the most prominent commonality between the visual and auditory modalities was the more coherent activation of an area including dorsolateral parts of precentral, juxtapositional, and prefrontal cortices in the hysteresis condition. These areas have not only been linked to bistability but also have specifically been connected with working memory and attention – two processes that could be crucial for hysteresis. Interestingly, we also found a more coherent activation at electrodes over the lateral occipital complex (LOC) during the hysteresis condition across both modalities. The LOC has been hypothesized to play a stabilizing role during visual bistability. Its involvement in auditory bistable perception has not been reported yet. We propose that hysteresis is evoked through a complex interplay of networks that have been associated with working memory and attention.
Keywords: brain, perceptual hysteresis, ambiguous stimuli, multistability, bistability, EEG, neural response