title: Local inhibition of GABA affects precedence effect in the inferior colliculus.
abstract: The precedence effect is a prerequisite for faithful sound localization in a complex auditory environment, and is a physiological phenomenon in which the auditory system selectively suppresses the directional information from echoes. Here we investigated how neurons in the inferior colliculus respond to the paired sounds that produce precedence-effect illusions, and whether their firing behavior can be modulated through inhibition with gamma-aminobutyric acid (GABA). We recorded extracellularly from 36 neurons in rat inferior colliculus under three conditions: no injection, injection with saline, and injection with gamma-aminobutyric acid. The paired sounds that produced precedence effects were two identical 4-ms noise bursts, which were delivered contralaterally or ipsilaterally to the recording site. The normalized neural responses were measured as a function of different inter-stimulus delays and half-maximal interstimulus delays were acquired. Neuronal responses to the lagging sounds were weak when the inter-stimulus delay was short, but increased gradually as the delay was lengthened. Saline injection produced no changes in neural responses, but after local gamma-aminobutyric acid application, responses to the lagging stimulus were suppressed. Application of gamma-aminobutyric acid affected the normalized response to lagging sounds, independently of whether they or the paired sounds were contralateral or ipsilateral to the recording site. These observations suggest that local inhibition by gamma-aminobutyric acid in the rat inferior colliculus shapes the neural responses to lagging sounds, and modulates the precedence effect.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Ningyu
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Neurophysiology, Capital Medical University, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jia
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Neurophysiology, Capital Medical University, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wen
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Li
keywords: NSFC grant; auditory center; echo suppression; gamma-aminobutyric acid; inferior colliculus; lagging stimulus; local inhibition; nerve regeneration; neural regeneration; precedence effect