Evoked potentials from the inferior colliculus in man

Sound-evoked potentials were recorded from the inferior colliculus in man when it was exposed during surgery. The earliest response to controlateral stimulation with 2000 Hz tone bursts at 90 dB was a positive deflection with a latency of about 6.5 msec that was followed by a slow, negative deflection that lasted about 5 msec. It is supposed that this surface-positive peak originates in the lateral lemniscus. Its latency matched that of the fifth vertex-positive wave (V) of the BSEP recorded from the scalp. Superimposed on the slow potential were several peaks. These peaks emerged clearly after the slow components were removed by filtering. The peaks then were shown to have latencies that matched the latencies of peaks VI, VII and VIII of the scalp-recorded BSEP.