Application of an automatic integrating system to the recording of spontaneous locomotor activity in small mammals

This paper describes an automatic system in which the rotation of the drum of a rotating activity cage turns by means of a crank, lever, ratchet, worm and gear, the shaft of a precision, linear, continuous-rotation potentiometer across which a constant potential difference is applied. The potential read off by the moving contact of the potentiometer is thus directly proportional to the number of rotations of the activity wheel. This potential is recorded at any desired interval by an automatic printing meter. By using a multi-point instrument a number of rotating cages can be monitored simultaneously.Any activity which can be made to rotate the potentiometer shaft can be recorded in the way described. Thus records can be obtained from bouncing cages, interruptions of light beams, drops, or any electrical contact, and of course the record could be made on magnetic or punched tapes or on punched cards to facilitate computer analysis, as well as on a printed chart as described.