title: New field with tonotopic organization in guinea pig auditory cortex.
abstract: In guinea pig auditory cortex, two core areas, a primary area (AI) and a dorsocaudal field (DC), and two belt regions ventral to AI and DC (VRB and VCB) with an intermediate zone (T) in between, together with a small field (S) rostral to AI, have been reported in single-electrode studies although field S and zone T have not been observed in imaging studies. Using a high-resolution in vivo optical-imaging system with the voltage-sensitive dye RH-795, we report here the successful imaging of a rostral small field and zone T and a ventral-to-dorsal frequency gradient in zone T. Further, we found that VRB can be subdivided into two areas, a ventrorostral field (VR) with properties similar to those reported for VRB, and a ventrocaudal field (VC) with novel properties. With increasing stimulus tone frequency, activation in VR shifted caudally while activation in VC shifted rostrally. Thus we have newly identified field VC that has mirror-symmetric tonotopy to that of VR.
authors.affiliation: Dept. of Sensory and Cognitive Physiology, Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Nishimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shirasawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaizo
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Song
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001303:Auditory Cortex / Q000033:anatomy & histology / Q000502:physiology*; D001306:Auditory Pathways / Q000033:anatomy & histology / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D006168:Guinea Pigs / Q000033:anatomy & histology / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D055095:Optics and Photonics / Q000295:instrumentation; D009949:Orientation / Q000502:physiology; D013045:Species Specificity; D013343:Styrenes; D009435:Synaptic Transmission / Q000502:physiology
chemical_list: C096453:RH 795; D013343:Styrenes