Optical imaging of neural activity in multiple auditory cortical fields ofguinea pigs

Neural activity of multiple fields in the auditory cortex of anesthetized g uinea pigs in response to pure tones was visualized by optical recording us ing a voltage-sensitive dye (RH795). Ten auditory fields were identified ba sed on the tonotopic organization and response latency: the core fields con sisting of the primary (Al) and secondary (All) fields and surrounding belt areas consisting of. dorso-anterior (IDA), dorsal (D), dorso-posterior (DP ), posterior (P), ventro-posterior (VP), ventro-medial (VM), ventro-anterio r (VA) and ventral (V) fields. Tonotopic organization was observed in all t he fields apart from DA, D, DP and V. Spatio-temporal displays suggest that the auditory information spreads from the core fields of Al and All to bel t fields via three distinct (dorsocaudal, caudal and ventrorostral) pathway s. NeuroReport 12:3335-3339 (C) 2001 Lippincott Williams & Wilkins.