Slow Late Component in Conditioned Stimulus-Evoked PotentialsFrom the Amygdala After Fear Conditioning in the Rat

[摘要] Male Wistar rats were subjected to adifferential Pavlovian fear conditioning procedurein which one of two tones (6 or 10 kHz)was followed by an electric shock (CS+) and theother was not (CS-). Before and after fearconditioning, we recorded the evoked potentialselicited byCS+andCS-from electrodes aimed atthe lateral nucleus of the amygdala. Beforeconditioning, a slow, negative component withpeak amplitude around 150 ms was present inthe evoked potentials. This component wassensitive to habituation. After fear conditioning,bothCS+andCS-elicited the same latecomponent, albeit with a larger amplitude. Thisenhancement was temporary: decreasingamplitude was observed in the course of CS testpresentations under extinction. Prior researchrevealed a comparable slow component in theamygdala of the cat under similar experimentalconditions. The collective results indicate thatthe large late component in the amygdala isenhanced by fear conditioning, suggesting thatsuch enhancement reflects the anticipation of abiologically significant event.

[学科分类] 精神健康和精神病学