Computer signal processing of long duration biotelemetric brain data.

The EEG represents brain processing under diverse physiological conditions. A complete system involving acquisition and quantitation of this important information about brain function is described. The time-domain EEG and other biological signals are obtained using a multichannel PAM/FM biotelemeter mounted on the head of the experimental animal. This data is transmitted, demodulated and recorded by electronic recording techniques. A computer-based EEG analysis system is described for acquiring the primary data and transforming it into the frequency domain using Fourier methods. The computing system is developed to semi-automatically signal process about 4 h of eight channel EEG records. Data compression by plotting in a quasi-three-dimensional spectral profile allows visual correlations of pattern features to drug manipulations, etc. The software programs are briefly described for each step in signal processing. The feasibility of the complete system approach is demonstrated using biotelemetry to acquire low voltage EEG signals without behavioral distortions or introduction of artifacts by cables.