Nishimura Masataka, Shirasawa Hiroshi, Kaizo Hiroyuki, Song Wen-Jie
Dept. of Sensory and Cognitive Physiology, Graduate School of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
J Neurophysiol. 2007 Jan;97(1):927-32. doi: 10.1152/jn.00689.2006. Epub 2006 Oct 18.
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.
在豚鼠听觉皮层中，单电极研究报告了两个核心区域，即初级区域（AI）和背尾场（DC），以及AI和DC腹侧的两个带状区域（VRB和VCB），两者之间有一个中间区（T），还有AI前方的一个小场（S），不过成像研究中未观察到场S和区域T。使用配备电压敏感染料RH-795的高分辨率体内光学成像系统，我们在此报告成功成像了前方小场和区域T以及区域T中从腹侧到背侧的频率梯度。此外，我们发现VRB可细分为两个区域，一个是腹侧前方场（VR），其特性与报道的VRB相似，另一个是腹侧尾场（VC），具有新特性。随着刺激音调频率增加，VR中的激活向尾侧移动，而VC中的激活向前方移动。因此，我们新确定了场VC，其具有与VR镜像对称的音频拓扑。
