This project involves the development and application of minicomputer and PC-based signal processing techniques for analysis of physiological signals, e.g., electrocardiogram, electromyogram, and electroencephalogram. The LAS minicomputer-based system provides a general A/D facility and ability to filter the signals with a variety of analog and digital techniques. In FY88 a new project has been undertaken to analyze heart rate variability (HRV) on free-living primates being studied by investigators at the Laboratory of Comparative Ethology (NICHD). Also in FY88, some signal processing activities have been shifted from mainframe or minicomputer to PC, using MATLAB, a matrix manipulating software package implemented on the IBM-XT.