THE REPRESENTATION OF ARM MOVEMENTS IN POSTCENTRAL AND PARIETAL CORTEX
THE REPRESENTATION OF ARM MOVEMENTS IN POSTCENTRAL AND PARIETAL CORTEX
复制标题
DOI：
10.1139/y88-075
复制
发表时间：
1988-04-01
影响因子：
2.1
通讯作者：
KALASKA, JF
中科院分区：
文献类型：
--
作者：
KALASKA, JF
相当多的实验证据支持这一假设，即动觉感觉背后的新皮层过程形成了一系列分层的细胞，这些细胞发出越来越复杂的身体运动模式的信号。然而，这一观点受到了批评，数据缺乏在受控条件下的定量验证。这些研究通常也使用一维（往复）运动，甚至是多自由度关节，如手腕或肩膀，并已被限制为被动运动。后一种限制是特别关键的，因为许多肌肉受体的反应受梭动活动的影响，而许多关节受体的反应对肌肉收缩活动的水平敏感。这两个因素在主动运动期间对这些受体产生的信号引入显著的动觉模糊性。这种模糊性在初级躯体感觉皮层本体感受细胞的放电中是明显的。在5区的研究表明，单细胞信号肩关节运动的形式广泛的方向调谐曲线。整个种群的活动模式编码了运动方向。这些细胞似乎对运动的空间方面进行了明确的编码，因为它们的放电对在不同负荷条件下产生相同运动所需的肌肉活动变化相对不敏感。目前还不能确定第5区的躯体感觉活动是一种在等级上上级于SI的连续的动觉表征，还是一种具有独立和不同功能的平行表征。
Considerable experimental evidence supports the hypothesis that the neocortical processes underlying kinesthetic sensation form a hierarchical series of cells signalling increasingly complex patterns of movement of the body. However, this view has been criticized and the data lack quantitative verification under controlled conditions. These studies have also typically used one-dimensional (reciprocal) movements, even of multiple degree-of-freedom joints such as the wrist or shoulder, and have been restricted to passive movements. This latter limitation is particularly critical, since the response of many muscle receptors is affected by fusimotor activity while that of many articular receptors is sensitive to the level of muscle contractile activity. Both factors introduce significant kinesthetic ambiguity to the signals arising from these receptors during active movement. This ambiguity is evident in the discharge of primary somatosensory cortex proprioceptive cells. Studies in area 5 show that single cells signal shoulder joint movements in the form of broad directional tuning curves. The pattern of activity of the entire population encodes movement direction. The cells appear to encode spatial aspects of movement unambiguously, since their discharge is relatively insensitive to the changes in muscle activity required to produce the same movements under different load conditions. It is not yet certain whether the somesthetic activity in area 5 is a kinesthetic representation that is sequential to and hierarchically superior to that in SI, or whether it is a parallel representation with separate and distinct functions.