Figure 1.

Diagram of the electrophysiological experimental circuit. A data acquisition unit (DAQ) converts the digital output from a PC to an analogue signal which triggers a signal generator to produce a stimulus pulse of the desired duration and voltage. This pulse is passed through an isolator; this enables the current to be increased if needed and isolates the recording part of the circuit from the power supply, reducing noise. The stimulus pulse is led through stainless steel electrodes into the experimental animal. Platinum recording electrodes record the resulting stimulus response which is amplified and filtered through a preamplifier. The DAQ then converts the analogue stimulus response to a digital signal which is stored on the PC. The recordings were carried out inside a Faraday cage.