Hypothermia causes adult-like retention deficits of prior learning in infant mice

Nine-day-old S-W mice receiving deep body hypothermia or hyperthermia immediately after escape training were retested 1 or 24 hr later. Results indicated that hypothermia impaired 24-hr retention but had no effect upon 1-hr memory. Hyperthermia had no effect, with the mice demonstrating retention of the escape response at both retest intervals. In Experiment 2, administration of hypothermia or hyperthermia 23 hr after original training had no effect upon memory nor did either treatment produce motoric deficits upon retest 1 hr following thermal exposure. Experiment 3 indicated that hypothermia administered immediately after training produced retention deficits directly related to amount of body temperature reduction following hypothermia. These data are similar to those obtained with adult mice and suggest that memory processes occurring in 9-day-old mice may represent the onset of functioning of processes underlying adult long-term memory.