Miniature three-function transmitting system for single neuron recording, wireless brain stimulation and marking.

A telemetric micro-transmitting system has been developed for extracellular single unit recording, electrical brain stimulation and marking of the recording and stimulation site in small freely moving animals. The action potentials are transmitted by using frequency modulation for distances up to 10 m. Electrical brain stimulation through the recording electrodes is performed by means of an inductively powered circuit which is combined with the transmitter (mass of the system 2.38 g). Biphasic current pulses can be applied. Pulse frequency and duration are wireless remotely controlled. The recording and stimulation site in the brain can be marked by means of iron deposits.