Design of a digital radio-frequency telemetry system for recording of electrophysiological data in freely moving rats

A wired system in which a rat resides in a copper mesh-shielded cage is presently used to collect EEG and other electrophysiological data from Sprague-Dawley rats in the Trinity College Electrophysiology Laboratories. We have designed a digital RF-telemetry system to replace those wires and to enhance flexibility in both experimental design and the animal's freedom of movement. Currently available systems using analog technology to transmit data from the animal to the recording apparatus are typically susceptible to noise and loss of data integrity, which is why such telemetric systems have not gained widespread acceptance in the research community. Our present all-digital telemetric design, however, permits multiple channels to be multiplexed and transmitted over a single channel, reducing noise and enhancing data integrity.