MISMATCH BETWEEN ANTICIPATED AND ACTUALLY PRESENTED SOUND STIMULI IN HUMANS

In a tone sequence of continuously ascending frequency or ascending in tensity, a tone was occasionally repeated. The repeated tone elicited an anterior negative wave, the latency of which was comparable to the mismatch negativity. However, the amplitude of the negative wave was l arger over the left hemisphere than over the right hemisphere. The neg ative wave might reflect a discrepancy between an expected tone and an actually presented tone.