NEURAL REPRESENTATION FOR THE TEMPORAL STRUCTURE OF SOUND PATTERNS

RESPONSES to infrequently exchanging two segments of a complex tonal p attern were tested for the presence of the mismatch negativity event-r elated brain potential component. This component is elicited when an a uditory stimulus differs from the sensory memory trace of the previous ly presented repetitive sound. Because the segments exchanged in the t onal pattern differed from each other only in their durations, the eli citation of the mismatch response revealed that the temporal structure of sound patterns is encoded in the traces underlying the mismatch pr ocess. Results showing that the mismatch response was elicited even wh en the tonal patterns were presented continuously (i.e. without silent intervals separating successive patterns) demonstrate the automatic d etection of periodicity in the acoustic stream.