Heather Read, PhD
Psychological Sciences and Biomedical Engineering
University of Connecticut
Cortical neural codes that could form the basis of rhythm and timbre perception
Auditory cortex is essential for mammals, including rodents, to detect rhythm and timbre cues in the sound envelope. However, how different cortical fields may contribute to this ability is a mystery. Previously, we found precise spiking patterns provide a potential neural code for sound shape cues in primary (A1) and non-primary (VAF, SRAF) auditory fields of the rat (Lee et al., 2016). Here, we extend these findings and characterize the time course of the temporally precise output and use a pairwise discrimination index and a Naïve Bayesian classifier to determine how these spiking patterns may be used at subsequent stages of the auditory pathway to discriminate and classify temporal cues in sound. We demonstrate for the first time that all three cortices provide temporal spiking patterns for robust sound shape discrimination but only the ventral non-primary cortices do so on long time scales. This study is significant as it supports the idea of a hierarchy for acoustic object perception where sensory processing and grouping of sound sequences happens on progressively longer time scales as one moves to more ventral non-primary auditory cortices. Furthermore, this suggests a universal principle that may prove important in other sensory systems.