Neural interactions in unilateral colliculus and between bilateral colliculi modulate auditory signal processing

Hui-Xian Mei,Qi-Cai Chen,Liang Cheng

doi:10.3389/fncir.2013.00068

Hui-Xian Mei, Qi-Cai Chen + Show 1 more

Open Access

https://doi.org/10.3389/fncir.2013.00068

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Abstract

In the auditory pathway, the inferior colliculus (IC) is a major center for temporal and spectral integration of auditory information. There are widespread neural interactions in unilateral (one) IC and between bilateral (two) ICs that could modulate auditory signal processing such as the amplitude and frequency selectivity of IC neurons. These neural interactions are either inhibitory or excitatory, and are mostly mediated by γ-aminobutyric acid (GABA) and glutamate, respectively. However, the majority of interactions are inhibitory while excitatory interactions are in the minority. Such unbalanced properties between excitatory and inhibitory projections have an important role in the formation of unilateral auditory dominance and sound location, and the neural interaction in one IC and between two ICs provide an adjustable and plastic modulation pattern for auditory signal processing.

Highlights

In sound reception, auditory signal processing has traditionally been explained by neural interactions of divergent and convergent projections within the ascending auditory system through the interplay between excitation and inhibition (Suga, 1997)
All sound signals in the range of audible frequency can be perceived by ear, we only notice those sounds interested by us and other sound signals that assumed to have no biological significance are filtered by excitatory or inhibitory modulation during transmission upward to different auditory nucleus
A number of studies have shown that auditory signal processing and integration in inferior colliculus (IC) are significantly modulated by the massive descending corticofugal system which adjusts and improves ongoing collicular signal processing in multipleparametric domains and reorganizes collicular auditory maps according to the acoustic experience (Jen et al, 1998; Jen and Zhou, 2003; Popelar et al, 2003; Yan et al, 2005; Zhou and Jen, 2007; Ma and Suga, 2008; Suga, 2008; Suga et al, 2010)

Summary

Introduction

Auditory signal processing has traditionally been explained by neural interactions of divergent and convergent projections within the ascending auditory system through the interplay between excitation and inhibition (Suga, 1997). To study the effect of neural interactions on sound amplitude and frequency selectivities of IC neurons, the auditory responses including the rate-intensity function (RIF) and frequency tuning curve (FTC) of each IC neuron in two simultaneously recorded IC neurons (or paired neurons) were examined under two-tone stimulation conditions.

Results

Conclusion