Activity-Recording Apparatus

an instrument to automatically record the activity cycle of animals. It is usually a cage with a movable bottom. As an experimental animal moves around in the cage, it exerts the weight of its body on the bottom of the cage. By means of a mechanical, pneumatic, or electrical actuator the displacement of the area is recorded on a tape which is stretched around a rotating drum so that the activity of the animal can be determined over a certain time interval.