Motor activity and the mesotelencephalic dopamine function. I. High-resolution temporal and genetic analysis of open-field behavior.

In a genetic selection experiment whose goal was to construct congenic neurological animal model lines with different mesotelencephalic dopamine systems, we produced foundation F2 generations derived from crosses (C57BL/6ByJXBALB/cJ and C57BL/6ByJXCXBI/ByJ) between highly inbred mouse lines with different dopamine systems. In this report, temporal distribution, latency, and genetic variability of open-field (OF) behavioral variables were investigated in order to establish a behavioral profile for the various generations and to provide behavioral data as a first step towards multivariate studies on correlations between OF behaviors and mesencephalic and striatal tyrosine hydroxylase activity. Analysis of the behavioral data provided evidence that measures of the open-field behaviors varied significantly across time segments of the test and that the temporal profiles of several behavioral variables were genotype-dependent. It is suggested that (1) OF behaviors have dynamic temporal profiles, and (2) temporal-genetic analysis can be a useful auxiliary method in the functional interpretation of behavior.