Infrared Transfer of Electrophysiologic Signals During Magnetic Resonan

Ronald M. Harper, John M. Parker*, Robert C. Frysinger, Luke A. Henderson, Walter del Vecchio** and Mary A. Woo***
Departments of Neurobiology, *Physiology and **Radiological Sciences, and the ***School of Nursing University of California at Los Angeles, Los Angeles, CA 90095

Assessment of electrophysiological signals is essential for determination of states during functional magnetic resonance brain imaging for sleep-related challenges. Such assessment is hindered by introduction of artifacts on the electrophysiological signals by the magnetic fields of the scanner, and, conversely, images can be distorted by contamination from artifacts introduced through metallic signal cables. We describe a low-cost infrared system for transferring electrophysiological signals from amplifiers near magnetic resonance scanners. The system consists of a multi-channel consumer infrared audio system, modified to respond to DC electrophysiological signal levels. The device transmits signals to externally-located receivers through an observation window. The exceptionally low-cost system minimizes induction of noise into magnetic resonance images, and reduces contamination of electrophysiological signals by the scanner.