Bistable Dynamics of Perceiving Ambiguous Stimuli

When experiencing an ambiguous sensory stimulus (e.g., the vase-faces image), subjects may report random alternations (time scale, seconds) between the possible interpretations. I will describe dynamical models with multiple time scales for neuronal populations that compete (fast time scale) through mutual inhibition for dominance – showing alternations (slow time scale). The models behave as noisy oscillators or as multistable systems subject to noise-driven switching. In highly idealized formulations networks are percept specific without direct representation of stimulus features. Our recent work involves perception of ambiguous auditory stimuli (e.g., http://auditoryneuroscience.com/scene-analysis/streaming-galloping-rhythm slider settings: rate=8, df=3 or 6 or 10). The models explicitly incorporate sound features — perceptual selectivity is emergent rather than built-in. I will compare modeling results with behavioral (human) data from our psychophysical experiments.