See what you hear – How the brain forms representations across the senses

Our senses are constantly bombarded with a myriad of signals. To make sense of this cacophony, the brain needs to integrate signals emanating from a common source, but segregate signals originating from the different sources. Thus, multisensory perception relies critically on inferring the world’s causal structure (i. e. one common vs. multiple independent sources). Behavioural research has shown that the brain arbitrates between sensory integration and segregation consistent with the principles of Bayesian Causal Inference. At the neural level, recent functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) studies have shown that the brain accomplishes Bayesian Causal Inference by dynamically encoding multiple perceptual estimates across the sensory processing hierarchies. Only at the top of the hierarchy in anterior parietal cortices did the brain form perceptual estimates that take into account the observer’s uncertainty about the world’s causal structure consistent with Bayesian Causal Inference.