Neural spikes as rare events

Abstract

We consider the information transmission problem in neurons and its possible implications for learning in neural networks. Our approach is based on recent developments in statistical physics and complexity science. Combining sensory information from various modalities for perceptual decision-making offers several advantages and is essential for the survival of both humans and animals. Not much is known about which brain regions are involved in spatial localization using audiovisual integration. We explore this further by training mice in a task requiring audiovisual integration. We then record from the secondary motor cortex (M2) using high-density electrophysiology. Analyzing this data, we found neurons responsive to multimodal as well as unimodal auditory and visual stimuli. The neurons are generally more responsive to auditory, rather than visual, stimuli. There was low correlation between the auditory and visual responses. Some neurons were sensitive to the task mode, whether active or passive, with more neurons being responsive in the active mode. A relatively large percentage of neurons (10-11%) differed significantly in their response to left and right-sided auditory stimuli, but only in 1 of the 3 mice we recorded from. These findings suggest a role for M2 in multisensory decision making and should enable further research in this field. We then use branching process simulations to model neural activity. This would support temporal coding theory as a model for neural coding.