NEURONAL MECHANISMS OF AUDITORY BACKWARD RECOGNITION MASKING IN MACAQUE AUDITORY-CORTEX

THE sensation of a single sound event can be altered by subsequent sou nds. This study searched for neural mechanisms of such retroactive eff ects in macaque auditory cortex by comparing neural responses to singl e tones with responses to two consecutive tones. Retroactive influence s were found to affect late parts of the response to a tone, which com prised 53/134 of the recordings of action potentials and 88/131 of the recordings of field potentials performed in primary, caudal, and medi al auditory fields. If before or during the occurrence of the late res ponse to the first tone a second tone was presented the late response was suppressed. Suppression of late cortical responses parallels perce ptual phenomena like backward recognition masking, suggesting that sup pression of late responses provides a neural correlate of auditory bac kward effects. NeuroReport 9: 2551-2555 (C) 1998 Rapid Science Ltd.