IMMEDIATE EXPANSION OF RECEPTIVE-FIELDS OF NEURONS IN AREA-3B OF MACAQUE MONKEYS AFTER DIGIT DENERVATION
IMMEDIATE EXPANSION OF RECEPTIVE-FIELDS OF NEURONS IN AREA-3B OF MACAQUE MONKEYS AFTER DIGIT DENERVATION
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DOI：
10.3109/08990229109144748
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发表时间：
1991-01-01
影响因子：
0.9
通讯作者：
TWEEDALE, R
中科院分区：
文献类型：
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作者：
CALFORD, MB;TWEEDALE, R
在五只猕猴中检查了全部或部分单位去神经对体感皮层（区域 3b）神经元感受野（Rds）的短期影响。在两只动物中，通过截肢去神经后，发现最初在截肢手指上记录有 Rds 的神经元的电极位置有从伤口延伸的新 Rds。新字段通常位于相邻数字上。具有部分截肢的初始 Rd 的神经元，或者在某些情况下接近但不在截肢的手指上的神经元，显示出剩余 RF 的相当大的扩展。对三只猴子使用局部麻醉来提供暂时的去神经支配。在这些实验中，电极被放置在两个皮质中的相同位置。去神经支配对侧皮质的影响与截肢相似。然而，当感觉恢复到数字后，扩大的 Rds 收缩了。在去神经支配同侧的皮质中，Rds 位于另一只未受影响的手上。它们也迅速扩张然后收缩，其时间进程与去神经对侧皮质中的对应物相同。由于扩张的快速性及其短期去神经支配的暂时性，该效应的基础可能是揭示现有但通常不表达的连接，这些连接通常受到去神经支配区域的完整输出的抑制。丘脑皮质传入神经的广泛树状区域为暴露的敏感性提供了潜在的来源。通常抑制大 Rds 表达的抑制机制尚不明显。然而，在其他物种中的研究表明，外周 C 纤维为中枢抑制回路提供了主要的输入来源。
The short-term effect of total or partial single-digit denervation on receptive fields (Rds) of neurons in somatosensory cortex (area 3b) was examined in five macaque monkeys. In two animals, after denervation by amputation, it was found that electrode positions that initially recorded neurons with Rds on the amputated digit had new Rds extending from the wound. Often the new fields were on adjacent digits. Neurons with initial Rds that were partially amputated, or in some cases close to but not on the amputated digit, showed considerable expansion of the remaining RF. In three monkeys local anesthesia was used to provide a temporary denervation. In these experiments electrodes were placed in equivalent positions in both cortices. The effect on cortex contralateral to the denervation was similar to that seen with amputation. However, after esthesia returned to the digit, the expanded Rds contracted. In cortex ipsilateral to the denervation, Rds were on the opposite unaffected hand. These also rapidly expanded and then contracted, with the same time course as their counterparts in cortex contralateral to the denervation. Because of the rapidity of the expansion and its temporary nature with short-term denervation, the basis of the effect is probably an unmasking of existing but normally unexpressed connections, which are normally inhibited by the intact output from the denervated area. The wide arborization fields of thalamocortical afferents provide a potential source for the unmasked sensitivity. A mechanism for the inhibition that normally suppresses the expression of large Rds is not readily apparent. However, work in other species suggests that peripheral C fibers provide the primary source of input to central inhibitory circuits.