Reproducibility of time structure in motor activity of rats under nocturnal conditions

Computer pattern recognition systems for the study of spontaneous rat behavior have introduced a new analytical technique, the K functions, that expands the definition of experimentally induced changes in behavior. Such studies normally evaluate three measures, a measure of the number of initiations of specific behavioral acts, a measure of the total time of each act, and a measure of behavioral time structure, the K functions. Such measures have been shown to be very stable and reproducible among control rats observed under normal light conditions. This study examines the stability of results from these three measures as applied to nine different groups of control Sprague-Dawley male rats observed under red light during their normal nocturnal hours. All three measures provided stable and reproducible results, but the measure of time structure, the K function analysis, provided the greatest consistency, producing values that vary by only a few percent.