Exploratory behaviour in two selectively-bred lines of mice after intrahippocampal injection of methylscopolamine

The temporal course of exploratory behaviour in male mice from two selected lines SRH (showing frequent rearing responses) and SRL (with less frequent rearing) following injection of methylscopolamine into the hippocampus was studied. The anticholinergic drug decreased exploration in the SRH line and prolonged it in the SRL line. The experiment supplies further proof that a cholinergic system in this brain area regulates responses to novelty and that this system is controlled by genetic factors.