SOMATOTOPIC ORGANIZATION OF THE 2ND SOMATOSENSORY AREA (SII) IN THE CEREBRAL-CORTEX OF THE MOUSE
SOMATOTOPIC ORGANIZATION OF THE 2ND SOMATOSENSORY AREA (SII) IN THE CEREBRAL-CORTEX OF THE MOUSE
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DOI：
10.3109/07367228609144585
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发表时间：
1986-01-01
期刊：
影响因子：
--
通讯作者：
SIMONS, DJ
中科院分区：
文献类型：
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作者：
CARVELL, GE;SIMONS, DJ
用钨微电极研究了垂体麻醉的成年小鼠顶叶皮层的躯体定位组织。在第一躯体感觉区（SI）的面部代表后面和侧面，发现对侧面部和身体的完整代表，面积约为4.0-4.5 mm 2。在第二躯体感觉区（SII）内，有以下发现：（1）爪和面的代表区相对较大，特别是与前上唇和眼肌触须有关的窦毛。这些身体区域的感受野是SII中最小的，尽管比SI中相应的感受野大。特别地，触须感受野总是包括至少几个相邻的触须，并且爪感受野总是包括至少两个相邻的趾。(2)在代表近端身体部位的区域中，感受野相当大，可能包括对侧和同侧肢体或躯干表面，有时包括整个身体和面部。(3)对躯体感觉和听觉刺激的反应在体内一致地被发现（即，躯干和肢体）表示，但很少发现在面部区域。(4)脸部最靠前，后肢和尾巴最靠后。前爪和后爪趾以及面部的前面（例如，口周窦毛和门齿）在侧面表示，而背部、尾侧头和触须肌在内侧表示。因此，在SII内，“肌肉”可以被视为具有直立的身体取向，其中面部区域与S1内的面部表示接界。(5)与SI相比，SII的特征在于不太明显的IV层，其厚度和堆积密度不规则，并且在V层中锥体细胞的分层中不太均匀。此外，SII通常从软脑膜到白色物质比SI厚。这些结果一般与小鼠诱发电位研究的早期发现雅阁，但与最近在小鼠和大鼠中报道的触须肌在SII中仅具有最小或不具有代表性不同。事实上，目前的研究结果表明，在SII的胡须的代表可能有一个专门的功能，在SI平行。
The somatotopic organization of the parietal cortex of barbituate-anesthetized, adult mice was studied using tungsten microelectrodes. A complete representation of the contralateral face and body occupying approximately 4.0-4.5 mm2 was found immediately posterior and lateral to the representation of the face in the first somatosensory area (SI). Within this second somatosensory ara (SII), the following findings were made: (1) A relatively large region is devoted to representations of the paws and face, especially the sinus hairs associated with the anterior upper lip and mystacial vibrissae. Receptive fields on these body regions are among the smallest found in SII, though larger than corresponding receptive fields in SI. In particular, vibrissae receptive fields always include at least several adjacent whiskers, and paw receptive fields always include at least two adjacent digits. (2) In regions representing proximal body parts, receptive fields are considerably larger, may include both contralateral and ipsilateral limb or trunk surfaces, and sometimes include the entire body and face. (3) Responses to both somatosensory and auditory stimulation were consistently found in the body (i.e., trunk and limb) representation, but rarely found in the face region. (4) The face is represented most anteriorly, and the hindlimb and tail most posteriorly. Forepaw and hindpaw digits and anterior aspects of the face (e.g., perioral sinus hairs and the incisors) are represented laterally, while the back, caudal head, and mystacial vibrissae are represented medially. Within SII, therefore, a "musculus" can be viewed as having an upright body orientation with the face area bordering the face representation within SI. (5) By comparison with SI, SII is characterized by a less pronounced layer IV, which is of irregular thickness and packing density, and by less uniformity in the layering of pyramidal cells in lamina V. In addition, SII is generally thicker from pia to white matter than SI. These results are in general accord with earlier findings from evoked potential studies in mice, but are at variance with recent reports in mice and rats that the mystacial vibrissae have only a minimal, or no, representation within SII. Indeed, the present findings suggest that the representation of the whiskers in SII may have a specialized function paralleling that in SI.