Figure 1.
Pup learning from odor-shock conditioning (0.5-mA shock) changes over development and is influenced by maternal (anesthetized) presence. Behavior was examined using a Y-maze test, (a) 8-d-old rats learned to prefer an odor paired with a shock, with or without maternal presence, (b) When conditioned without maternal presence, 12- to 15-d-old pups subjected to paired odor-shock learned an odor aversion. Pups that were conditioned with maternal presence learned an odor preference. (c) Pups of weaning age (21 to 23 d old) learned odor avoidance with or without maternal presence. *P < 0.05. Error bars represent s.e.m.