Infralimbic cortex activation increases c-Fos expression in intercalated neurons of the amygdala

S. Berretta, H. Pantazopoulos, M. Caldera, P. Pantazopoulos, Denis Pare

Research output: Contribution to journalArticle

154 Citations (Scopus)

Abstract

Recently, it was reported that stimulation of the infralimbic cortex produces a feedforward inhibition of central amygdala neurons. The interest of this observation comes from the fact that the central nucleus is the main output station of the amygdala for conditioned fear responses and evidence that the infralimbic cortex plays a critical role in the extinction of conditioned fear. However, the identity of the neurons mediating this infralimbic-evoked inhibition of the central nucleus remains unknown. Likely candidates are intercalated amygdala neurons. Indeed, these cells receive glutamatergic afferents from the infralimbic cortex, use GABA as a transmitter, and project to the central amygdala. Thus, the present study was undertaken to test whether, in adult rats, the infralimbic cortex can affect the activity of intercalated neurons. To this end, disinhibition of the infralimbic cortex was induced by local infusion of the non-competitive GABA-A receptor antagonist picrotoxin. Subsequently, neuronal activation was determined bilaterally within the amygdala using induction of the immediate early gene Fos. Infralimbic disinhibition produced a significant increase in the number of Fos-immunoreactive intercalated cells bilaterally whereas no change was detected in the central nucleus. In the basolateral amygdaloid complex, increases in the number of Fos-immunoreactive cells only reached significance in the contralateral lateral nucleus. These results suggest that glutamatergic inputs from the infralimbic cortex directly activate intercalated neurons. Thus, our findings raise the possibility that the infralimbic cortex inhibits conditioned fear via the excitation of intercalated cells and the consequent inhibition of central amygdala neurons.

Original languageEnglish (US)
Pages (from-to)943-953
Number of pages11
JournalNeuroscience
Volume132
Issue number4
DOIs
StatePublished - Jan 1 2005

Fingerprint

Interneurons
Amygdala
Fear
Neurons
GABA-A Receptor Antagonists
Picrotoxin
Immediate-Early Genes
gamma-Aminobutyric Acid
Central Amygdaloid Nucleus
Inhibition (Psychology)

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Keywords

  • Extinction
  • Fear
  • GABA
  • Immediate early gene
  • Picrotoxin

Cite this

Berretta, S. ; Pantazopoulos, H. ; Caldera, M. ; Pantazopoulos, P. ; Pare, Denis. / Infralimbic cortex activation increases c-Fos expression in intercalated neurons of the amygdala. In: Neuroscience. 2005 ; Vol. 132, No. 4. pp. 943-953.
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Infralimbic cortex activation increases c-Fos expression in intercalated neurons of the amygdala. / Berretta, S.; Pantazopoulos, H.; Caldera, M.; Pantazopoulos, P.; Pare, Denis.

In: Neuroscience, Vol. 132, No. 4, 01.01.2005, p. 943-953.

Research output: Contribution to journalArticle

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