TIME-COURSE OF LOUDNESS IN TONE PATTERNS IS AUTOMATICALLY REPRESENTEDBY THE HUMAN BRAIN

The present study investigated the neural mechanisms of intensity codi ng by presenting human subjects repetitively with tone pairs consistin g of two tones differing in intensity. The first tone was higher in so und pressure level than the second (70 versus 58 dB SPL). Infrequent o rder reversals of the two tones elicited the mismatch negativity (MMN) , an event-related brain potential probe of preattentive auditory sens ory memory. This finding indicates that the human auditory system auto matically encodes information about the time course of intensity withi n tone patterns into neural representations.