Two measures of activity in genetically defined mice as a function of strain, time of day, and previous experience

Abstract

Genetically defined adult mice from progenitor strains C57BL/6 and BALB/c and the 7 recombinant inbred strains derived from them were tested at one of five times of day for amount of locomotor and investigatory activity in three 16-min sessions. Strain, sex, time of day, and experiential factors are shown to interact in variable and complex fashion. Previous reports of a single major gene’s determining activity level are contradicted. Observed genetically determined differences were not in concordance with strain distribution patterns for other genetically determined traits. Interpretation of locomotor and investigatory activity as separable behaviors is supported. Habituation (activity decrement) both within and between sessions is added to the behaviors amenable to behavior genetic investigations.