Discharges in Human Muscle Receptor Afferents during Block Grasping
Discharges in Human Muscle Receptor Afferents during Block Grasping
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DOI：
10.1523/jneurosci.3357-08.2008
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发表时间：
2008-11-26
影响因子：
5.3
通讯作者：
Edin, Benoni B.
中科院分区：
文献类型：
--
作者：
Dimitriou, Michael;Edin, Benoni B.
人类抓握依赖于前馈控制，通过感觉反馈在线监测和校正。虽然支撑手与物体相互作用的大部分感觉机制是已知的，但缺乏有关实际物体接触之前和之后阶段肌肉受体反应的信息。因此，我们让受试者用他们的拇指和手指抓住块给他们，而我们记录肌肉传入的拇指和手指伸肌沿着手腕和手指的运动学，和肌电图活动。该任务的运动学与“正常”抓握没有区别。没有传入编码对象接触或手指并置。初级和次级传入的父母肌肉的长度比预期从以前的研究，以及从他们的反应，强加的长度变化，他们的父母肌肉的相位先进。因此，初级和次级传入神经的放电与其母体肌肉的肌腱速度和初级传入神经的加速度有很好的相关性，而两者都没有出现编码肌肉长度。如果将高尔基体腱器传入神经的放电与肌梭传入神经的放电一起沿着考虑，则肌肉长度变化的解码速度显著提高。我们认为这些发现可以用收缩肌肉的生物力学特性来解释。此外，我们的结论是，似乎不太可能，在这项任务中记录的肌梭传入有任何作用，在提供“本体感受”的信息有关的大小的物体掌握。
Human grasping relies on feedforward control that is monitored and corrected on-line by means of sensory feedback. While much of the sensory mechanisms underpinning hand-object interaction are known, information has been lacking about muscle receptor responses during the phases before and after actual object contact. We therefore let subjects use their thumb and fingers to grasp blocks presented to them while we recorded muscle afferents from the thumb and finger extensor muscles along with wrist and digit kinematics, and electromyographic activity. The kinematics of the task was indistinguishable from "normal" grasping. None of the afferents encoded either object contact or finger apposition. Both primary and secondary afferents were more phase advanced on the parent muscle lengths than expected from previous studies as well as from their responses to imposed length changes of their parent muscles. Thus, the discharges of both primary and secondary afferents were well correlated to the tendon velocity of their parent muscles and that of primary afferents also to acceleration whereas neither appeared to encode muscle length as such. Decoding the velocity of muscle length changes were significantly improved if the discharge of Golgi tendon organ afferents were taken into account along with that of the muscle spindle afferents. We propose that these findings may be explained by the biomechanical properties of contracting muscles. Moreover, we conclude that it seems unlikely that the muscle spindle afferents recorded in this task have any role in providing "proprioceptive" information pertaining to the size of an object grasped.