SOMATOSENSORY CORTICAL MAP CHANGES FOLLOWING DIGIT AMPUTATION IN ADULT MONKEYS
SOMATOSENSORY CORTICAL MAP CHANGES FOLLOWING DIGIT AMPUTATION IN ADULT MONKEYS
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DOI：
10.1002/cne.902240408
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
ZOOK, JM
中科院分区：
文献类型：
--
作者：
MERZENICH, MM;NELSON, RJ;ZOOK, JM
应用微电极标测技术，对成年夜猴2-8月龄手3b区的皮质结构进行了研究。在第3指或第2指和第3指的外科截肢之后。手指神经被绑住，以防止其在截肢残端内再生。在几只猴子身上获得连续的地图，以确定随着时间的推移，同一个体的地图组织变化的性质。在所有研究的猴子中，相邻手指和手掌表面的表征在地形上扩展，占据了以前代表截肢手指的大部分或全部皮层区域。随着这些周围皮肤表面的代表的扩大，它们的放大倍数增加了几倍，而感受野区域大致相应地减少。随着放大倍数的增加，周围的皮肤表面表示在相应的更细的颗粒，这意味着规则有关的感受野重叠分离的距离在整个皮层的感受野的大小逐渐减少，动态保持。在截肢之后，数字表示之间的不连续性经历了显著的移位（通常移位数百μ m），并且在通常分离的扩展数字表示（例如，数字1和4）在重组地图中彼此接近，这意味着这些地图不连续性通常是动态保持的。感受野大小的变化与周围皮肤表面的代表性扩大到剥夺皮质区有一个空间分布和时间过程类似的人类截肢者的残肢上的感觉敏锐度的变化。这表明，经验依赖性地图的变化导致感官能力的变化。主要的地形变化局限于在截肢手指代表的初始边界两侧的500-700 μ m的皮质区。更远的地区似乎没有重组（即，没有被来自周围皮肤表面的输入占据），甚至在截肢后许多个月。一些皮肤表面的代表性整体移动到以前的领土内的代表性截肢的手指在每只猴子研究的位置。在人类中，没有错位错误或感知失真的结果，从周围的表面刺激的数字截肢。这进一步证明，任何给定的皮肤表面都可以由这些皮层区域中不同生命时期的许多替代功能图来表示。体感皮层地图的基本功能（感受野的大小，皮质网站的代表给定的皮肤表面，代表性的不连续性，并可能submodality列边界）是动态维护。皮质皮肤表面地图是可变的经验，在成年人中，经验依赖地图的变化反映，并可能占伴随的触觉能力的变化。这些结果承担这些皮质地图动态的机制的影响。
The cortical representations of the hand in area 3b in adult owl monkeys were defined with use of microelectrode mapping techniques 2-8 mo. after surgical amputation of digit 3, or both digits 2 and 3. Digital nerves were tied to prevent their regeneration within the amputation stump. Successive maps were derived in several monkeys to determine the nature of changes in map organization in the same indiviuals over time. In all monkeys studied, the representations of adjacent digits and palmar surfaces expanded topographically to occupy most or all of the cortical territories formerly representing the amputated digit(s). With the expansion of the representations of these surrounding skin surfaces there were severalfold increases in their magnification and roughly corresponding decreases in receptive field areas. With increases in magnification, surrounding skin surfaces were represented in correspondingly finer grain, implying that the rule relating receptive field overlap to separation in distance across the cortex was dynamically maintained as receptive fields progressively decreased in size. The discontinuities between the representations of the digits underwent significant translocations (usually by hundreds of .mu.m) after amputation, and sharp new discontinuous boundaries formed where usually separated, expanded digital representations (e.g., of digits 1 and 4) approached each other in the reorganizing map, implying that these map discontinuities are normally dynamically maintained. Changes in receptive field sizes with expansion of representations of surrounding skin surfaces into the deprived cortical zone had a spatial distribution and time course similar to changes in sensory acuity on the stumps of human amputees. This suggests that experience-dependent map changes result in changes in sensory capabilities. The major topographic changes were limited to a cortical zone 500-700 .mu.m on either side of the initial boundaries of the representation of the amputated digits. More distant regions did not appear to reorganize (i.e., were not occupied by inputs from surrounding skin surfaces) even many months after amputation. The representations of some skin surfaces moved in entirety to locations within the former territories of representation of amputated digits in every monkey studied. In man, no mislocation errors or perceptual distortions result from stimulation of surfaces surrounding a digital amputation. This constitutes further evidence that any given skin surface can be represented by many alternative functional maps at different times of life in these cortical fields. Basic features of somatosensory cortical maps (receptive field sizes, cortical sites of representation of given skin surfaces, representational discontinuities, and probably submodality column boundaries) are dynamically maintained. Cortical skin surface maps are alterable by experience in adults, and experience dependent map changes reflect and possibly account for concomitant changes in tactual abilities. These results bear implications for mechanisms underlying these cortical map dynamics.