Facilitative effects of maternal environmental enrichment on maze learning in rat offspring.

Pregnant rats were differentially reared in enriched (EC), impoverished (IC), and standard colony conditions (SC) through the pregnancy. Half of the male offspring were reared by their biological mothers and the remaining half were reared by foster-mothers. After weaning male offspring were tested in the Hebb-Williams maze apparatus. The effect of environment was significant for the total error scores; the EC group had less errors than the IC group. In a second experiment all male offspring (EC, SC and IC) were reared by foster-mothers. The effect of environment was significant for initial, repetitive, and total error scores. Further analysis revealed that the EC-SC and EC-IC differences were significant, whereas the IC-SC difference was not. Thus, the results obtained were the first to reveal that maternal environmental enrichment during pregnancy can exert a facilitatory influence on the postnatal maze learning abilities of the offspring.