FEAR CONDITIONING ENHANCES SHORT-LATENCY AUDITORY RESPONSES OF LATERAL AMYGDALA NEURONS - PARALLEL RECORDINGS IN THE FREELY BEHAVING RAT

The lateral nucleus of the amygdala (LA) is the first site in the amyg dala where the plasticity underlying fear conditioning could occur. We simultaneously recorded from multiple LA neurons in freely moving rat s during fear conditioning trials in which tones were paired with foot shocks. Conditioning significantly increased the magnitude of tone-el icited responses (often within the first several trials), converted un responsive cells into tone-responsive ones, and altered functional cou plings between LA neurons. The effects of conditioning were greatest o n the shortest latency (less than 15 ms) components of the tone-elicit ed responses, consistent with the hypothesis that direct projections f rom the auditory thalamus to LA are an important link in the circuitry through which rapid behavioral responses are controlled in the presen ce of conditioned fear stimuli.