Bakin J S, Kwon M C, Masino S A, Weinberger N M, Frostig R D
Center for the Neurobiology of Learning and Memory, University of California, Irvine 92717, USA.
Cereb Cortex. 1996 Mar-Apr;6(2):120-30. doi: 10.1093/cercor/6.2.120.
The suprathreshold tonotopic organization of rat and guinea pig auditory cortex was investigated using intrinsic signal optical imaging through a thinned skull. Optical imaging revealed that suprathreshold pure sine wave tone stimulation (25-80 dB) evoked activity over large cortical areas that were tonotopically organized. Three-dimensional surface plots of the activated areas revealed "patchy' auditory-evoked activity consisting of numerous local peaks and valleys building to a maximum. Subsequent detailed electrophysiological mapping in the same subjects confirmed the localization of auditory-evoked activity based on optical imaging, including responses to a test frequency at cortical loci more than 2 octaves away from the threshold-defined isofrequency contour. The success of this technique in visualizing auditory cortex functional organization at suprathreshold stimulus levels will allow for future investigations of auditory cortex frequency representation, including representational plasticity induced by a variety of experimental manipulations.
通过薄颅骨利用内在信号光学成像技术研究了大鼠和豚鼠听觉皮层的阈上音频拓扑组织。光学成像显示，阈上纯正弦波音调刺激（25 - 80分贝）在音频拓扑组织的大皮层区域诱发了活动。激活区域的三维表面图显示出“斑块状”听觉诱发活动，由众多局部峰值和谷值组成，形成一个最大值。随后在同一受试者中进行的详细电生理图谱绘制证实了基于光学成像的听觉诱发活动定位，包括对距离阈值定义的等频轮廓超过2个八度的皮层位点处测试频率的反应。该技术在阈上刺激水平可视化听觉皮层功能组织方面的成功，将为未来听觉皮层频率表征的研究提供可能，包括各种实验操作诱导的表征可塑性研究。
