Microcomputer analysis and display of canine small intestinal electrical activity

1741-0444

Analogue filtering and digital analysis ; Apple computer ; Gastrointestinal motility ; Spike counting

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Medicine

Abstract A system combining analogue filtering and digital counting was used to study the canine intestinal EMG. Recordings were made in conscious dogs from electrodes previously sutured to the serosa of the small intestine at operation under halothane/nitrous oxide anaesthesia. Signals recorded on cassette tape were replayed 60 times faster than the recording speed. After filtering the output was half-wave rectified and passed to Schmitt triggers with variable gain for adjustment of the input voltage. This triggered a monostable multivibrator which produced a 1 ms output pulse. The pulses were taken to three flag switches of the Apple lle Games Controller An Assembler program read the value at the flag locations every millisecond, incremented a temporary store and transferred the contents of the counter into a memory location when an interrupt was received every second by a clock. The data were displayed to show patterns of EMG activity and used for quantification of the results. This system provides a low-cost, flexible method of analysing intestinal EMG which avoids analogue-to-digital conversion.

Electronic Resource