Auditory and Vestibular SystemsOptical recording of responses to frequency-modulated sounds in the auditory cortexHorikawa, Junsei1,2; Nasu, Masahiro1; Taniguchi, Ikuo1Author Information 1Department of Neurophysiology, Medical Research Institute, Tokyo Medical and Dental University, Kanda-surugadai 2-3-10, Chiyoda-ku, Tokyo 101, Japan 2Corresponding Author: Junsei Horikawa ACKNOWLEDGEMENTS: This work was supported by a Grant-in-Aid for Scientific Research (08680924) from the Ministry of Education, Science, Sports and Culture, Japan. Received 11 December 1997; accepted 11 January 1998 NeuroReport: March 30th, 1998 - Volume 9 - Issue 5 - p 799-802 Buy Abstract USING an optical recording method with a voltage-sensitive dye, we recorded activities in the primary auditory cortex (AI) of anesthetized guinea pigs in response to frequency-modulated (FM) sounds and sounds with stepwise changes in frequency (SF). Responses to the FM sound showed a spatiotemporal pattern in which a localized active spot traversed the isofrequency bands in the AI, and they differed from the band-like responses to the SF sound. These results indicate that time-varying sounds are represented as spatiotemporal activation of tonotopic organization in the AI by spectral cues with interactions between frequency bands. © Lippincott-Raven Publishers.