Characteristics of evoked potentials of the human brain during recognition of short acoustic stimuli of different frequencies.

We report here studies of the efficiency of recognition of short acoustic signals (11-30 msec) whose presentation did not produce mismatch negativity in evoked potentials in the human brain. Nonetheless, stimuli could still be recognized efficiently in these conditions; processing negativity disappeared from evoked potentials and the efficiency of recognition was significantly worsened on presentation of the shortest stimuli (11 msec). It is suggested that processing negativity also has a critical duration for acoustic signals, though this is significantly shorter than the minimum duration of stimuli needed for generating mismatch negativity.