A battery of behavioral tests yielding 79 measures, many of which were presumably related to learning and memory, was administered to house mice of seven inbred strains. An analysis of the factorial structure indicated that the two principal and most pervasive factors underlying performance on the battery involved the initiation and maintenance of locomotor activity. Thus, many of the genetically assisted behavioral differences between strains which have heretofore been considered to involve differences in learning and memory actually represent genetically associated differences in facets of activity. Chemical analyses of the brains of mice of the seven strains revealed substantial relations between the enzymes choline acetylase and monoamine oxidase and the activity maintenance factor. Among the amino acids, taurine and gamma-aminobutyric acid were shown to have substantial relations with the activity initiation factor. Thus, there do indeed appear to be some likely functional relations between some classes of behavior and specific neurotransmitter systems within the brain. (Author)