Rats' behavior in the course of aversive conditioning measured by a stabilimeter

Aversive behaviors of rats to the conditioned stimulus in the course of cla ssical conditioning of a light (CS) and electric-shock (US) were analyzed u sing a stabilimeter. For the Classical Conditioning (CC) group (n=5), CS wa s preceded 5 s to US (1 s) using delayed conditioning procedure in the 3 da ily sessions each of which was consisted of 30 reinforcing trials. For the US group (n=5), US (1 s) was presented at the same time as CC group without any CS. The results showed that the activity of the CC group during CS inc reased as the trials progressed, but it was not changed in the US group. Th us, animals made various kinds of activities during the CS, and these were not reflexes to the presentation of the CS but were responses that have lon g latencies.