Role of cortical feedback in the receptive field structure and nonlinear response properties of somatosensory thalamic neurons

A. A. Ghazanfar, D. J. Krupa, M. A.L. Nicolelis

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

Previous studies have suggested that the descending pathway from the primary somatosensory (SI) cortex to the ventral posterior nucleus of the thalamus has only a mild facilitative influence over thalamic neurons. Given the large numbers of corticothalamic terminations within the rat somatosensory thalamus and their complex topography, we sought to examine the role of corticothalamic feedback in the genesis of spatiotemporal receptive fields and the integration of complex tactile stimuli in the thalamus. By combining focal cortical inactivation (produced by microinjection of the GABAA agonist muscimol), with chronic multielectrode recordings, we observed that feedback from the rat SI cortex has multiple influences on its primary thalamic relay, the ventral posterior medial (VPM) nucleus. Our data demonstrate that, when single-whisker stimuli were used, the elimination of cortical feedback caused significant changes in the spatiotemporal structure of the receptive fields of VPM neurons. Cortical feedback also accounted for the nonlinear summation of VPM neural responses to simultaneously stimulated whiskers, in effect "linearizing" the responses. These results argue that the integration and transmission of tactile information through VPM are strongly influenced by the state of SI cortex.

Original languageEnglish (US)
Pages (from-to)88-100
Number of pages13
JournalExperimental Brain Research
Volume141
Issue number1
DOIs
StatePublished - Jan 1 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Keywords

  • Barrel cortex
  • Combination sensitivity
  • Corticofugal
  • Corticothalamic
  • Dynamic receptive fields
  • Rat

Fingerprint Dive into the research topics of 'Role of cortical feedback in the receptive field structure and nonlinear response properties of somatosensory thalamic neurons'. Together they form a unique fingerprint.

Cite this