Habituation in rodents: a review of behavior, neurobiology, and genetics.

Habituation to a novel environment in rodents is commonly defined as a change in exploratory or locomotor activity over time (intrasession) or with repeated exposures (intersession). While numerous neuroactive substances are known to influence habituation, neurotransmitters that play particularly important roles are serotonin, acetylcholine, dopamine and glutamate. Although habituation is a complex process, studies over the past two decades have demonstrated that there is a genetic component. At present, although researchers are still attempting to isolate key genes that control habituation, findings in mutant mice have begun to highlight some of the genes that could play a role. The challenge will be in deciphering what genes are directly involved in the process of habituation, what genes indirectly influence habituation through a secondary mechanism, and what genes have no role in habituation but are only affected as part of the downstream cascade.