Spatiotemporal mapping of the neural markers of prediction error processing across multisensory and unisensory modalities

Abstract

Prediction errors in the brain are indexed by two event related potentials - MMN and P300 which are elicited whenever there is a violation of regularity in occurrence of a repetitive stimulus. While, MMN reflects the brain's ability to perform automatic comparisons between consecutive stimuli and provides an electrophysiological index of sensory error detection, P300 is associated with cognitive processes such as attention and memory. Till date, there has been extensive research on the roles of MMN and P300 individually, because of their potential to be used as clinical markers of consciousness and attention, respectively. However, the relationship between these two ERPs, in context of prediction error propagation is an open question. Secondly, whether these events represent modality specific or modality independent information processing needs to be tested in unisensory and multisensory environments. Our EEG study on 22 healthy human volunteers shows that multisensory prediction errors are temporally facilitated by the constituent unisensory modality that has shorter processing latencies at any stage of prediction error processing. Employing source localization using individual participant's MRI scan, our study reveals that the corresponding ERP generators underlying the temporal hierarchy of prediction mismatch signals in the brain transition from being modality sensitive to modality independent across both unisensory and multisensory contexts. Such knowledge can be of immense value in clinical research for determining the stages of various treatments in aging, schizophrenia and depression, and their efficacy on cognitive function.