Show Reference: "Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem"

Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem In Integrative Functions in the Mammalian Auditory Pathway, Vol. 15 (2002), pp. 99-159, doi:10.1007/978-1-4757-3654-0_4 by Tom C. T. Yin edited by Donata Oertel, Richard R. Fay, Arthur N. Popper
@incollection{yin-2002,
    abstract = {When an animal hears a sound in its environment, there are several important tasks that the auditory system must try to accomplish. Two major jobs are to determine what it was that produced the sound and where it comes from. Understanding how the nervous system can accomplish these tasks is a major goal of modern auditory neurobiological research. In this book, we explore what is known about these questions at several different levels of the auditory system. The purpose of this chapter is to review the anatomical and physiological mechanisms in the auditory brainstem of mammals that encode where a sound originates. Specifically, this chapter examines the two binaural localization cues: interaural time disparities ({ITDs}) and interaural level disparities ({ILDs}) (For abbreviations, see Table 1). The neural mechanisms of sound localization are of particular interest since the location of a stimulus is not represented in the sensory epithelium, as it is in the visual or somatosensory systems, but must be computed by combining input from the two ears in the central auditory system. To a large degree, we understand how these cues are encoded by single cells at this level of the auditory system. Indeed, it appears that certain cells in the auditory brainstem are highly specialized to facilitate the encoding of these cues, and more is known about the central processing of sound localization cues than of any other auditory function (e.g., pitch perception, vowel discrimination).},
    author = {Yin, Tom C. T.},
    booktitle = {Integrative Functions in the Mammalian Auditory Pathway},
    citeulike-article-id = {13421832},
    citeulike-linkout-0 = {http://dx.doi.org/10.1007/978-1-4757-3654-0\_4},
    citeulike-linkout-1 = {http://link.springer.com/chapter/10.1007/978-1-4757-3654-0\_4},
    doi = {10.1007/978-1-4757-3654-0\_4},
    editor = {Oertel, Donata and Fay, Richard R. and Popper, Arthur N.},
    keywords = {auditory, localization, neural-coding},
    pages = {99--159},
    posted-at = {2014-11-07 10:49:52},
    priority = {2},
    publisher = {Springer-Verlag},
    series = {Springer Handbook of Auditory Research},
    title = {Neural Mechanisms of Encoding Binaural Localization Cues in the Auditory Brainstem},
    url = {http://dx.doi.org/10.1007/978-1-4757-3654-0\_4},
    volume = {15},
    year = {2002}
}

See the CiteULike entry for more info, PDF links, BibTex etc.

In mammals, different neurons in the lateral superior olive (LSO) are tuned to different ILDs.

In mammals, different neurons in the medial superior olive (MSO) are tuned to different ITDs.

Subregions of the superior olivary complex (SOC) extract auditory localization cues.

ITD and ILD are most useful for auditory localization in different frequency ranges:

  • In the low frequency ranges, ITD is most informative for auditory localization.
  • In the high frequency ranges, ILD is most informative for auditory localization.

Auditory localization is different from visual or haptic localization since stimulus location is not encoded in which neural receptors are stimulated but in the differential temporal and intensity pattern of stimulation of receptors in the to ears.

It's easier to separate a target sound from a blanket of background noise if target sound and background noise have different ITDs.

Interaural time and level difference do not help (much) in localizing sounds in the vertical plane. Spectral cues—cues in the change of the frequencies in the sound due to differential reflection from various body parts—help us do that.

There seem to be significant differences in SOC organization between higher mammals and rodents.

Jeffress' model has been extremely successful, although neurophysiological evidence is scarce (because the MSO apparently is hard to study).

Jeffress' model predicts a spatial map of ITDs in the MSO.

Jeffress' model predicts a spatial map of ITDs in the MSO. Recent evidence seems to suggest that this map indeed exists.