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

Aversive behaviors of rats to the conditioned stimulus in the course of classical conditioning of a light (CS) and electric-shock (US) were analyzed using a stabilimeter. For the Classical Conditioning (CC) group (n = 5), CS was preceded 5 s to US (l s) using delayed conditioning procedure in the 3 daily sessions each of which was consisted of 30 reinforcing trials. For the US group (n = 5), US (l 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 increased as the trials progressed, but it was not changed in the US group. Thus, 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 long latencies.