Differential assessment of retrograde amnesia produced by Hypothermia following one-trial avoidance conditioning

Two different measures of the retention of avoidance conditioning, frequently used in the investigation of retrograde anmesia (RA), were examined. Rats were given a single training trial on either passive or active avoidance in a conventional black-white discrimination apparatus and step•through latencies were recorded. Task sequence, footshock and hypothermia were experimentally varied across eight groups of subjects. Each S was returned to the experimental apparatus 24 hours after training and given retention tests on both passive and active avoidance tasks. Test trial latencies failed to demonstrate any retention deficits attributable to RA, and both passive and active avoidance test latencies significantly increased. The results were interpreted in terms of the suppression o.f behavior resulting from conditioned emotionality, and serious questions were raised concerning the validity of singletrial avoidance latency measures.