Hamsters through time's window: temporal structure of hamster locomotor rhythmicity

The temporal patterns of running-wheel locomotor activity of a group of 15 golden hamsters (Mesocricetus auratus) are described in detail. The temporal patterns of activity and the behavior of activity bouts in these animals provide the basis for a hypothetical multioscillator framework underlying locomotor activity. The framework consists of a pacemaker that controls the transitions between two continuous states, activity time and rest time, each composing approximately half of the circadian cycle. Activity time appears as a "window" during which the expression of locomotor bouts controlled by additional circadian oscillators is permitted. In our model, whether or not locomotor activity is expressed as well as its detailed temporal pattern are functions of the phase relationships between the window pacemaker and bout oscillators.