A Species Difference in Conditioned Emotional Response

Abstract

A technique to produce a quantitative measure of CER without pretraining is presented. The response, a change in S's exploratory activity during the CS, occurs rapidly in even 3-wk. old rats and mice. Species differences occur in the reaction to CS, US, and CS-US pairings. Although rats tend to suppress activity during CS as a result of CS-US pairings, the shock or buzzer alone increases activity level; while the opposite is true of mice.