Low-cost automatic activity data recording system

We describe a low-cost, high quality device capable of monitoring indirect activity by detecting touch-release events on a conducting surface, i.e., the animal's cage cover. In addition to the detecting sensor itself, the system includes an IBM PC interface for prompt data storage. The hardware/software design, while serving for other purposes, is used to record the circadian activity rhythm pattern of rats with time in an automated computerized fashion using minimal cost computer equipment (IBM PC XT). Once the sensor detects a touch-release action of the rat in the upper portion of the cage, the interface sends a command to the PC which records the time (hours-minutes-seconds) when the activity occured. As a result, the computer builds up several files (one per detector/sensor) containing a time list of all recorded events. Data can be visualized in terms of actograms, indicating the number of detections per hour, and analyzed by mathematical tools such as Fast Fourier Transform (FFT) or cosinor. In order to demonstrate method validation, an experiment was conducted on 8 Wistar rats under 12/12-h ligh/dark cycle conditions (lights on at 7:00 a.m.). Results show a biological validation of the method since it detected the presence of circadian activity rhythm patterns in the behavior of the rats.

Cost effective computerised analysis of biological signals.

A data acquisition system--using self designed and assembled A/D and D/A converter board and appropriate software--has been developed for the International Business Machine (IBM) Personal Computer and has been used for spectral analysis of bio-electric signals. Spectral analysis of EEG signals was performed and the reliability confirmed by analysis of the same data by a standard systemdeveloped by Dynalog Inc, USA. The cutting edge of the system however, lies in its extreme low cost, combined with the versatility offered due to it being a computer based system.