Scalp evoked potentials to tone pips were recorded for nine subjects while performing a visual tracking task. The pips, which differed in intensity (40 & 60dB), were presented as either frequent or infrequent stimuli. These stimuli were randomly presented under three stimulus conditions which were determined in terms of probability (0.10 or 0.40) and number of infrequent stimuli (24 or 96) in one run. It was shown that the amplitude of the P
3 wave (around 340ms latency) in response to the infrequent stimuli was larger for the low probability condition than for the high probability condition, while no effect on the P
3 amplitude was found for the numbers of the stimuli.
抄録全体を表示