Interaural timing cues do not contribute to the map of space in the ferret superior colliculus : A Virtual acoustic space study

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

22 Scopus Citations
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Author(s)

  • Robert A. A. Campbell
  • Timothy P. Doubell
  • Fernando R. Nodal
  • Jan W. H. Schnupp
  • Andrew J. King

Detail(s)

Original languageEnglish
Pages (from-to)242-254
Journal / PublicationJournal of Neurophysiology
Volume95
Issue number1
Publication statusPublished - Jan 2006
Externally publishedYes

Abstract

In this study, we used individualized virtual acoustic space (VAS) stimuli to investigate the representation of auditory space in the superior colliculus (SC) of anesthetized ferrets. The VAS stimuli were generated by convolving broadband noise bursts with each animal's own head-related transfer function and presented over earphones. Comparison of the amplitude spectra of the free-field and VAS signals and of the spatial receptive fields of neurons recorded in the inferior colliculus with each form of stimulation confirmed that the VAS provided an accurate simulation of sounds presented in the free field. Units recorded in the deeper layers of the SC responded predominantly to virtual sound directions within the contralateral hemifield. In most cases, increasing the sound level resulted in stronger spike discharges and broader spatial receptive fields. However, the preferred sound directions, as defined by the direction of the centroid vector, remained largely unchanged across different levels and, as observed in previous free-field studies, varied topographically in azimuth along the rostrocaudal axis of the SC. We also examined the contribution of interaural time differences (ITDs) to map topography by digitally manipulating the VAS stimuli so that ITDs were held constant while allowing other spatial cues to vary naturally. The response properties of the majority of units, including centroid direction, remained unchanged with fixed ITDs, indicating that sensitivity to this cue is not responsible for tuning to different sound directions. These results are consistent with previous data suggesting that sensitivity to interaural level differences and spectral cues provides the basis for the map of auditory space in the mammalian SC. Copyright © 2006 The American Physiological Society.

Citation Format(s)

Interaural timing cues do not contribute to the map of space in the ferret superior colliculus : A Virtual acoustic space study. / Campbell, Robert A. A.; Doubell, Timothy P.; Nodal, Fernando R.; Schnupp, Jan W. H.; King, Andrew J.

In: Journal of Neurophysiology, Vol. 95, No. 1, 01.2006, p. 242-254.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review