Monday, July 23, 2007
Novel environments stimulate memory molecules
Remembering something requires changes in how our nerve cells talk to each other, and a process called long termed potentiation, or LTP, is regarded as a good model for one such underlying change. LTP refers to an enhancement of the synapse between two nerve cells such that an action potential arriving in a presynaptic terminal causes a larger voltage change in the postsynaptic terminal. This process is thought to require the synthesis of new proteins in the synapse and is essential in establishing long term memories(LTM). Moncada and Viola have made the interesting observation that weak inhibitory avoidance training, which induces short- but not long-term memory (LTM), can be consolidated into LTM by an exploration to a novel, but not a familiar, environment occurring close in time to the training session. "This memory-promoting effect caused by novelty depends on activation of dopamine D1/D5 receptors and requires newly synthesized proteins in the dorsal hippocampus. The results indicate the existence of a behavioral tagging process in which the exploration to a novel environment provides the plasticity-related proteins to stabilize the inhibitory avoidance memory trace."