Abstract/Details

Ipsilateral sound-evoked inhibition in the MNTB


2004 2004

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Abstract (summary)

There now exist rigorous accounts of how processing arises in auditory brainstem. Two prominent examples are the coding of interaural time differences (ITDs) and interaural level differences (ILDs), the major cues to azimuthal sound location. Nevertheless, recent findings have led us to revise our concepts of how these circuits operate. In this thesis, I focus on one such finding: the occurrence of ipsilateral sound-evoked inhibition in the medial nucleus of the trapezoid body (MNTB), an important nucleus in the ILD coding brainstem circuit. Previously, theory and empirical work had suggested that the MNTB is a monaural nucleus, receiving only contralateral excitation. However, I demonstrate that inhibition is stronger in young (P16–P19) than in adult gerbils, that it operates at physiologically realistic ILDs, and that the locus of inhibition is presynaptic to the MNTB, probably at the globular bushy cells in the ventral cochlear nucleus (VCN) that innervate it. In support of these findings, I present acoustic data which defines the range of natural ILDs for young and adult gerbils. The physiological findings are discussed in the contexts of development, ILD coding, ITD coding, and non-azimuth related coding. The most likely sources of the inhibition are considered and experiments to further pinpoint the source and the consequences for the MNTB and its targets are suggested.

Indexing (details)


Subject
Neurology
Classification
0317: Neurology
Identifier / keyword
Biological sciences; Auditory brainstem; Ipsilateral sound; Medial nucleus of the trapezoid body
Title
Ipsilateral sound-evoked inhibition in the MNTB
Author
Green, Joshua
Number of pages
152
Publication year
2004
Degree date
2004
School code
0146
Source
DAI-B 64/12, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
Advisor
Sanes, Dan H.
University/institution
New York University
University location
United States -- New York
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3114193
ProQuest document ID
305165659
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305165659
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