Traces of learning in the auditory localization pathway

Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305

Abstract

One of the fascinating properties of the central nervous system is its ability to learn: the ability to alter its functional properties adaptively as a consequence of the interactions of an animal with the environment. The auditory localization pathway provides an opportunity to observe such adaptive changes and to study the cellular mechanisms that underlie them. The midbrain localization pathway creates a multimodal map of space that represents the nervous system's associations of auditory cues with locations in visual space. Various manipulations of auditory or visual experience, especially during early life, that change the relationship between auditory cues and locations in space lead to adaptive changes in auditory localization behavior and to corresponding changes in the functional and anatomical properties of this pathway. Traces of this early learning persist into adulthood, enabling adults to reacquire patterns of connectivity that were learned initially during the juvenile period.

Footnotes

↵ * To whom reprint requests should be addressed.
This paper was presented at the National Academy of Sciences colloquium “Auditory Neuroscience: Development, Transduction, and Integration,” held May 19–21, 2000, at the Arnold and Mabel Beckman Center in Irvine, CA.
Abbreviations:

ITD,

interaural time difference;

ILD,

interaural level difference;

ICC,

the central nucleus of the inferior colliculus;

ICX,

the external nucleus of the inferior colliculus;

NMDA,

N-methyl-d-aspartate;

AP5,

d,l-2-amino-5-phosphonopentanoic acid;

GABA,

γ-aminobutyric acid