Telemetry system for reliable recording of action potentials from freely moving rats.
Recording single cells from alert rats currently requires a cable to connect brain electrodes to the acquisition system. If no cable were necessary, a variety of interesting experiments would become possible, and the design of other experiments would be simplified. To eliminate the need for a cable we have developed a one-channel radiotelemetry system that is easily carried by a rat. This system transmits a signal that is reliable, highly accurate and can be detected over distances of > or = 20 m. The mobile part of the system has three components: (1) a headstage with built-in amplifiers that plugs into the connector for the electrode array on the rat's head; the headstage also incorporates a light-emitting diode (LED) used to track the rat's position; (2) a backpack that contains the transmitter and batteries (2 N cells); the backpack also provides additional amplification of the single cell signals; and (3) a short cable that connects the headstage to the backpack; the cable supplies power to the headstage amplifiers and the LED, and carries the physiological signals from the headstage to the backpack. By using a differential amplifier and recording between two brain microelectrodes the system can transmit action potential activity from two nearly independent sources. In a future improvement, two transmitters with different frequencies would be used telemeter signals from four microelectrodes simultaneously.
Hawley
Emerson S
ES
Department of Physiology, SUNY Health Sciences Center at Brooklyn, New York 11203, USA.
Hargreaves
Eric L
EL
Kubie
John L
JL
Rivard
Bruno
B
Muller
Robert U
RU
D000200:Action Potentials; D000818:Animals; D001921:Brain / Q000502:physiology*; D008839:Microelectrodes; D051381:Rats; D013686:Telemetry / Q000295:instrumentation*