Krubitzer L, Künzle H, Kaas J
Department of Psychology, University of California, Davis 95616, USA.
J Comp Neurol. 1997 Mar 17;379(3):399-414.
We identified subdivisions of somatosensory cortex, and the borders and extents of auditory and visual cortex in Madagascan tenrecs (Echinops telfairi) by using microelectrode recording techniques and cortical myeloarchitecture. There was evidence for three distinct somatosensory fields. The primary somatosensory area (S1) contained an orderly representation of the contralateral body surface that stained darkly for myelin. Neurons were activated by light touch, and receptive fields were often small, especially for the snout. Immediately rostral to S1, a lightly myelinated rostral field (R) also contained a representation of the contralateral body, although the internal topography was not fully determined. Neurons in R responded to manipulations of body parts and tissue displacements. A small, moderately myelinated area lateral to S1 was termed PV/S2 because it possessed features that were similar to both the parietal ventral area (PV) and the second somatosensory area (S2) in other mammals. Neurons in PV/S2 responded to light tactile stimulation. A densely myelinated oval of cortex caudal to PV/S2, the auditory area (A), contained neurons that responded to clicks, and the densely myelinated caudomedial visual area (V) contained neurons that were activated by stimulation of one or both eyes. Some characteristics of V were similar to the primary visual area (V1) described in other mammals. A visual area located in rostromedial cortex (RV) contained neurons that were highly responsive to visual stimulation. Area RV may be a specialization of tenrecs or an elaboration of a visuomotor field that has been retained in most extant mammals. The results support the view that most of the neocortex of primitive mammals was composed of a few sensory areas. J. Comp. Neurol. 379:399-414, 1997.
我们通过使用微电极记录技术和皮质髓鞘结构，确定了马达加斯加猬（艾氏刺猬）体感皮层的细分区域，以及听觉和视觉皮层的边界与范围。有证据表明存在三个不同的体感区域。初级体感区（S1）包含对侧身体表面的有序表征，髓磷脂染色较深。神经元对轻触有反应，感受野通常较小，尤其是在口鼻部。紧邻S1前方，一个髓鞘较薄的吻侧区（R）也包含对侧身体的表征，尽管其内部拓扑结构尚未完全确定。R区的神经元对身体部位的操作和组织位移有反应。S1外侧一个中等髓鞘化的小区域被称为PV/S2，因为它具有与其他哺乳动物的顶叶腹侧区（PV）和第二体感区（S2）相似的特征。PV/S2区的神经元对轻触觉刺激有反应。PV/S2后方一个髓鞘密集的椭圆形皮质区域，即听觉区（A），包含对点击声有反应的神经元，而髓鞘密集的尾内侧视觉区（V）包含对一只或两只眼睛的刺激有反应的神经元。V区的一些特征与其他哺乳动物中描述的初级视觉区（V1）相似。位于吻内侧皮质的视觉区（RV）包含对视觉刺激高度敏感的神经元。RV区可能是刺猬的一种特化结构，或者是大多数现存哺乳动物中保留的视觉运动区的一种扩展。这些结果支持了这样一种观点，即原始哺乳动物的大部分新皮质由少数感觉区域组成。《比较神经学杂志》379:399 - 414, 1997年。
