Microcomputer-driven digital data processing of mouse actograph activity.

The system is designed to measure the ambulatory activity of each of a set of eight mice, using a group of actographs driven by an inexpensive microcomputer, thus avoiding unnecessary usage of a costly instrument over an extended period. A toric actograph was chosen since it is sensitive to ambulatory activity even at low amplitudes. In this computerized system, actograph data are recorded on audio cassettes during the experiment, and later reread by an Apple II microcomputer for storage on floppy disks. This makes it possible to perform all types of mathematical treatment at a later date. Since the experiments last for several days and the environment is kept constant, activity rhythms can be studied. The data processing takes place off-line and employs digital filtering, which is shown to be preferable for the presentation of temporal data to a simple smoothing, by a moving average. Spectral analysis is obtained through a discrete Fourier transform. Two methods of reconstitution of temporal curves from the frequency analyses are presented: an inverse Fourier transform, or summation of the Fourier series.