Multistable bimodal perceptual coding within the ventral premotor cortex.

Abstract

How neurons in the ventral premotor cortex (VPC) integrate and process multimodal sensory information remains unclear. We recorded VPC neuronal activity in two monkeys performing a tactile or acoustic bimodal detection task (BDT). Single-cell analyses revealed purely tactile, purely acoustic, bimodal, and decision-mnemonic responses. Population analyses of the VPC network and a recurrent neural network trained on the BDT uncovered notably similar latent dynamics. In both networks, neural trajectories diverged sharply from rest along modality-specific directions during stimulus presentation, while remained at rest during stimulus-absent trials. Subsequently, trajectories rotated toward a mnemonic subspace, where perceptual decisions (acoustic, tactile, and absent) were maintained in three distinctly different stable attractors. Using low-dimensional modeling, we propose a universal mechanism for the transition from sensory processing to memory retention explaining both biological and artificial latent neural dynamics in a simple dynamical motif. These results show that VPC neurons encode bimodal information, can integrate competing sensory inputs, and maintain multimodal perceptual decisions.