Abstract
Exposing rats to an enriched environment over an extended period of time has been shown to enhance hippocampal longβterm potentiation (LTP). Whether such prolonged exposure to environmental manipulation is necessary for LTP enhancement and whether the environmentally induced enhancement can persist long after the cessation of the environmental manipulation remain unknown. Using a novelty exposure procedure modified from the method of neonatal handling, we exposed neonatal rats to a nonβhome environment for 3 min/day during the first 3 weeks of life. We examined the LTP of both population spikes and excitatory postsynaptic potentials (EPSPs), in vitro, in the CA1 of the hippocampus during adulthood (7β8 and 13β14 months of age). We found that both the LTP of population spikes and the LTP of EPSPs were enhanced among animals who experienced neonatal novelty exposure. These results demonstrate that effective environmental enhancement of LTP can be achieved by as brief and as transient a manipulation as a 3βmin/day exposure over the first 3 weeks of life. The resulting enhancement can outlast the environmental manipulation by at least 1 year. Hippocampus 2002;12:398β404. Β© 2002 WileyβLiss, Inc.