Merzenich M M, Kaas J H, Wall J, Nelson R J, Sur M, Felleman D
Neuroscience. 1983 Jan;8(1):33-55. doi: 10.1016/0306-4522(83)90024-6.
Two to nine months after the median nerve was transected and ligated in adult owl and squirrel monkeys, the cortical sectors representing it within skin surface representations in Areas 3b and 1 were completely occupied by 'new' and expanded representations of surrounding skin fields. Some occupying representations were 'new' in the sense that (1) there was no evidence that these skin surfaces were represented in this region prior to median nerve transection; and (2) these skin surfaces retained their normal representation elsewhere within these two cortical representations of hand surfaces. Large 'new' representations of the dorsal surfaces of digits 1 and 2 (innervated by the radial nerve) and large 'new' representations of the hypothenar eminence (innervated by the ulnar nerve) were consistently recorded. Some surrounding skin surface representations expanded into the former median nerve zone, so that bordering skin surfaces (the ulnar insular palmar pad, the third digital palmar pad, glabrous ulnar digit 3, radial hand dorsum) were represented over far larger than normal cortical areas. These expanded representations of always-innervated skin sometimes appeared to move in entirety into the former median nerve representational zone (e.g. in the zone of representation of glabrous digit 4) were also consistently recorded. Reorganizational changes following median nerve sections were much more variable in Area 1 than in Area 3b. The topographic order of the reorganized cortical zone was comparable to normal. In at least most cortical sectors, there was a consistent, maintained relationship between receptive field size and magnification, i.e. as representations enlarged, receptive fields were correspondingly reduced in size. These studies indicate that topographic representations of the skin surface in adult monkeys are maintained dynamically. They clearly reveal that this projection system retains a self-organizing capacity in adult monkeys. They suggest that processes perhaps identical to a part of the original developmental organizing processes (by which details of field topographics are established) are operational throughout life in this projection system in primates. Some of the implications of these studies for the neural origins of tactile perception are discussed.
在成年猫头鹰猴和松鼠猴的正中神经被切断并结扎两到九个月后，在3b区和1区的皮肤表面表征中，代表正中神经的皮质区域被周围皮肤区域的“新的”且扩大的表征完全占据。一些占据的表征是“新的”，体现在：（1）没有证据表明在正中神经切断之前这些皮肤表面在该区域有表征；（2）这些皮肤表面在手部表面的这两个皮质表征中的其他地方保留了其正常表征。 consistently记录到了第1和第2指背侧（由桡神经支配）的大的“新”表征以及小鱼际隆起（由尺神经支配）的大的“新”表征。一些周围皮肤表面表征扩展到了以前的正中神经区域，以至于相邻的皮肤表面（尺侧岛状掌垫、第3指掌垫、无毛的尺侧第3指、桡侧手背）在比正常大得多的皮质区域有表征。这些始终有神经支配的皮肤的扩大表征有时似乎整体移入了以前的正中神经表征区域（例如在无毛第4指的表征区域）也被 consistently记录到。正中神经切断后的重组变化在1区比在3b区更具变异性。重组皮质区的拓扑顺序与正常情况相当。在至少大多数皮质区域，感受野大小和放大倍数之间存在一致的、保持的关系，即随着表征扩大，感受野大小相应减小。这些研究表明成年猴皮肤表面的拓扑表征是动态维持的。它们清楚地表明这个投射系统在成年猴中保留了自组织能力。它们表明，也许与最初发育组织过程（通过该过程建立场拓扑细节）的一部分相同的过程在灵长类动物的这个投射系统中终生起作用。讨论了这些研究对触觉感知神经起源的一些影响。
