Lasting increases in basolateral amygdala activity after emotional arousal: Implications for facilitated consolidation of emotional memories

  1. Joe Guillaume Pelletier1,
  2. Ekaterina Likhtik1,
  3. Mohammed Filali, and
  4. Denis Paré2
  1. Center for Molecular & Behavioral Neuroscience, Rutgers State University, Newark, New Jersey 07102, USA

Abstract

Manipulations that reduce or enhance the activity of basolateral amygdala (BLA) neurons in the minutes to hours after training have been shown to respectively impair or facilitate retention on the inhibitory avoidance task. Although this suggests that BLA activity is altered after emotional arousal, such changes have not been directly demonstrated. To test this, we devised a feline analog of the inhibitory avoidance task and recorded BLA unit activity before and after a single inescapable footshock. Single-unit recordings revealed that the firing rate of many BLA neurons gradually increased after the footshock, peaking 30–50 min post-shock and then subsiding to baseline levels 2 h later. During this period of increased activity, the discharges of simultaneously recorded BLA cells were more synchronized than before the shock. Although it was known that pairing innocuous (conditioned stimulus, CS) and noxious stimuli modifies the responsiveness of BLA neurons to the CS, our results constitute the first demonstration that emotional arousal produces lasting increases in the spontaneous firing rates of BLA neurons. We propose that these changes in BLA activity may promote Hebbian interactions between coincident but spatially distributed activity patterns in BLA targets, facilitating the consolidation of emotional memories.

Footnotes

  • Article and publication are at http://www.learnmem.org/cgi/doi/10.1101/lm.88605.

  • 1 These authors contributed equally to this work.

    • Accepted January 4, 2005.
    • Received November 2, 2004.
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