Short term synaptic depression improves information transfer in perceptual multistability

Zachary P Kilpatrick

doi:10.3389/fncom.2013.00085

Abstract

Competitive neural networks are often used to model the dynamics of perceptual bistability. Switching between percepts can occur through fluctuations and/or a slow adaptive process. Here, we analyze switching statistics in competitive networks with short term synaptic depression and noise. We start by analyzing a ring model that yields spatially structured solutions and complement this with a study of a space-free network whose populations are coupled with mutual inhibition. Dominance times arising from depression driven switching can be approximated using a separation of timescales in the ring and space-free model. For purely noise-driven switching, we derive approximate energy functions to justify how dominance times are exponentially related to input strength. We also show that a combination of depression and noise generates realistic distributions of dominance times. Unimodal functions of dominance times are more easily told apart by sampling, so switches induced by synaptic depression induced provide more information about stimuli than noise-driven switching. Finally, we analyze a competitive network model of perceptual tristability, showing depression generates a history-dependence in dominance switching.

Highlights

Ambiguous sensory stimuli with two interpretations can produce perceptual rivalry (Blake and Logothetis, 2002)
The oscillation results from a combination of depression and mutual inhibition, which produces population dominance times and can be sampled to give information about the strength of the stimulus that produced them
Once noise is added to these low dimensional oscillations, dominance time distributions still remain relatively tight, which can be sampled to infer relative contrasts of each input

Summary

Introduction

Ambiguous sensory stimuli with two interpretations can produce perceptual rivalry (Blake and Logothetis, 2002). Presenting two orthogonal gratings to either eye results in perception switching between gratings repetitively—binocular rivalry (Leopold and Logothetis, 1996). Perceptual rivalry can be triggered by a single stimulus with two interpretations, like the Necker cube (Orbach et al, 1963). The switching process in perceptual rivalry is considerably stochastic—a histogram of the dominance times of each percept spreads across a broad range (Fox and Herrmann, 1967). Senses other than vision exhibit perceptual rivalry. When two different odorants are presented to the two nostrils, a similar phenomenon occurs with olfaction, termed “binaral” rivalry (Zhou and Chen, 2009). Similar experiences have been evoked in the auditory (Deutsch, 1974; Pressnitzer and Hupé, 2006) and tactile (Carter et al, 2008) system

Methods

Results

Conclusion