Functional role of the secondary visual cortex in multisensory facilitation in rats

J Hirokawa, M Bosch, Shuzo Sakata, Y Sakurai, T Yamamori

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Recent studies reveal that multisensory convergence can occur in early sensory cortical areas. However, the behavioral importance of the multisensory integration in such early cortical areas is unknown. Here, we used c-Fos immunohistochemistry to explore neuronal populations specifically activated during the facilitation of reaction time induced by the temporally congruent audiovisual stimuli in rats. Our newly developed analytical method for c-Fos mapping revealed a pronounced up-regulation of c-Fos expression particularly in layer 4 of the lateral secondary visual area (V2L). A local injection of a GABA A receptor agonist, muscimol, into V2L completely suppressed the audiovisual facilitation of reaction time without affecting responses to unimodal stimuli. Such a selective suppression was not found following the injection of muscimol into the primary auditory and visual areas. To examine whether or not the rats might have shown the facilitated responses because of increment of stimulus intensity caused by the two modal stimuli, the behavioral facilitation induced by the high-intensity unimodal stimuli was tested by the injection of muscimol into V2L, which turned out not to affect the facilitation. These results suggest that V2L, an early visual area, is critically involved in the multisensory facilitation of reaction time induced by the combination of auditory and visual stimuli.
LanguageEnglish
Pages1402-17
Number of pages16
JournalNeuroscience
Volume153
Issue number4
DOIs
Publication statusPublished - 2008

Fingerprint

Muscimol
Visual Cortex
Injections
GABA-A Receptor Agonists
Auditory Cortex
Up-Regulation
Immunohistochemistry
Population

Keywords

  • acoustic stimulation
  • analysis of variance
  • animals
  • brain mapping
  • muscimol
  • photic stimulation
  • probability
  • proto-oncogene proteins c-fos
  • psychophysics
  • rats
  • up-regulation
  • visual cortex

Cite this

Hirokawa, J ; Bosch, M ; Sakata, Shuzo ; Sakurai, Y ; Yamamori, T. / Functional role of the secondary visual cortex in multisensory facilitation in rats. In: Neuroscience. 2008 ; Vol. 153, No. 4. pp. 1402-17.
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Functional role of the secondary visual cortex in multisensory facilitation in rats. / Hirokawa, J; Bosch, M; Sakata, Shuzo; Sakurai, Y; Yamamori, T.

In: Neuroscience, Vol. 153, No. 4, 2008, p. 1402-17.

Research output: Contribution to journalArticle

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