Fear Conditioning Induces a Lasting Potentiation of Synaptic Currents in Vitro

Nature. 1997 Dec 11;390(6660):607-11. doi: 10.1038/37605.

Abstract

The amygdala plays a critical role in the mediation of emotional responses, particularly fear, in both humans and animals. Fear conditioning, a conditioned learning paradigm, has served as a model for emotional learning in animals, and the neuroanatomical circuitry underlying the auditory fear-conditioning paradigm is well characterized. Synaptic transmission in the medial geniculate nucleus (MGN) to lateral nucleus of the amygdala (LA) pathway, a key segment of the auditory fear conditioning circuit, is mediated largely through N-methyl-D-aspartate (NMDA) and non-NMDA (such as alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)) glutamate receptors; the potential for neural plasticity in this pathway is suggested by its capacity to support long-term potentiation (LTP). Here we report a long-lasting increase in the synaptic efficacy of the MGN-LA pathway attributable to fear-conditioning itself, rather than an electrically induced model of learning. Fear-conditioned animals show a presynaptic facilitation of AMPA-receptor-mediated transmission, directly measured in vitro with whole-cell recordings in lateral amygdala neurons. These findings represent one of the first in vitro measures of synaptic plasticity resulting from emotional learning by whole animals.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amygdala / physiology
  • Animals
  • Conditioning, Classical*
  • Excitatory Postsynaptic Potentials
  • Fear / physiology*
  • Geniculate Bodies / physiology
  • Long-Term Potentiation / physiology
  • Male
  • Neurons / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, AMPA / metabolism
  • Synapses / physiology*

Substances

  • Receptors, AMPA