Corticofugal modulation of acoustically induced fos expression in the rat auditory pathway

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Xia Sun
  • Qiang Xia
  • Chun-Hong Lia
  • Daisy Kwok-Yan Shum
  • Ying-Shing Chan

Detail(s)

Original languageEnglish
Pages (from-to)509-525
Journal / PublicationJournal of Comparative Neurology
Volume501
Issue number4
Publication statusPublished - 1 Apr 2007
Externally publishedYes

Abstract

To investigate the corticofugal modulation of acoustic information ascending through the auditory pathway of the rat, immunohistochemical techniques were used to study the functional expression of Fos protein in neurons. With auditory stimulation at different frequencies, Fos expression in the medial geniculate body (MGB), inferior colliculus (IC), superior olivary complex, and cochlear nucleus was examined, and the extent of Fos expression on the two sides was compared. Strikingly, we found densely Fos-labeled neurons in all divisions of the MGB after both presentation of an auditory stimulus and administration of a γ-aminobutyric acid type A (GABAA) antagonist (bicuculline methobromide; BIM) to the auditory cortex. The location of Fos-labeled neurons in the ventral division (MGv) after acoustic stimulation at different frequencies was in agreement with the known tonotopic organization. That no Fos-labeled neurons were found in the MGv with acoustic stimuli alone suggests that the transmission of ascending thalamocortical information is critically governed by corticofugal modulation. The dorsal (DCIC) and external cortices (ECIC) of the IC ipsilateral to the BIM-injected cortex showed a significantly higher number of Fos-labeled neurons than the contralateral IC. However, no difference in the number of Fos-labeled neurons was found between the central nucleus of the IC on either side, indicating that direct corticofugal modulation occurs only in the ECIC and DCIC. Further investigations are needed to assess the functional implications of the morphological differences observed between the descending corticofugal projections to the thalamus and the IC. © 2007 Wiley-Liss, Inc.

Research Area(s)

  • Activity marker, Audition, Cochlear nucleus, Inferior colliculus, Medial geniculate body, Superior olive

Citation Format(s)

Corticofugal modulation of acoustically induced fos expression in the rat auditory pathway. / Sun, Xia; Xia, Qiang; Lia, Chun-Hong et al.
In: Journal of Comparative Neurology, Vol. 501, No. 4, 01.04.2007, p. 509-525.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review