Impaired reaching and grasping after focal inactivation of globus pallidus pars interna in the monkey
Impaired reaching and grasping after focal inactivation of globus pallidus pars interna in the monkey
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DOI：
10.1152/jn.1999.82.5.2049
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发表时间：
1999-11-01
影响因子：
2.5
通讯作者：
Mink, JW
中科院分区：
文献类型：
--
作者：
Wenger, KK;Musch, KL;Mink, JW
本研究的目的是验证这样一种假设，即内侧苍白球(GPI)的基底节输出有助于抑制竞争性运动模式，以防止它们干扰意志运动。为了验证这一假设，用GABA(A)激动剂Muscimol在GPI中局部失活之前和之后，对猴子的自然伸展、抓取和取回任务的运动学进行了测量。两只恒河猴被训练在一个旁矢状面伸手抓住一个L厘米长的苹果方块并将其取出。将反光标记应用于肩部、肘部、手腕和食指。在60个场地拍摄运动/S，数字化，离线分析。在每一次训练中，猴子分别进行12-15个伸展前和12-15个伸展后的伸展，L注射8.8 mM蝇香酚0.5亩。在GPI的“手臂”区域的22个不同的位置注射了麝香酚。在伸展-抓取-取回任务中，用蝇草酚使GPI失活会产生运动缺陷，这可以概括为：i)在伸展到目标的过程中手腕的峰值速度降低；2)肘部和肩部的角速度降低，肘部的角速度相对比肩部的角速度受损更严重；导致3)伸展顶端的最大垂直手腕和食指位置更高；4)从伸展结束到完成抓取的潜伏期延长；以及5)取回的损害比伸展更小，大多数部位的失活不会造成损害，尽管伸展缓慢，但一些实际上加快了取回速度。这项研究的结果表明，在以前正常的猴子中，GPI局部失活后，伸展运动以特定的方式受损。正常(或快速)提取的REACH减慢表明，很难抑制REACH之前活跃的、但有助于提取的姿势保持机制。这种损害的性质支持这样的假设，即GPI损伤破坏了抑制竞争运动机制的能力，以防止它们干扰所需的自愿运动。
The purpose of this study was to test the hypothesis that the basal ganglia output from globus pallidus pars interna (GPi) contributes to inhibition of competing motor patterns to prevent them from interfering with a volitional movement. To test this hypothesis, the kinematics of a natural reach, grasp, and retrieval task were measured in the monkey before and after focal inactivation in GPi with the GABA(A) agonist muscimol. Two rhesus monkeys were trained to reach in a parasagittal plane to grasp a l-cm cube of apple and retrieve it. Reflective markers were applied to the shoulder, elbow, wrist, and index finger. Movements were videotaped at 60 fields/s, digitized, and analyzed off-line. In each session the monkey performed 12-15 reaches before and 12-15 reaches after injection of 0.5 mu l of 8.8 mM muscimol. Muscimol was injected into 22 separate locations in the "arm" area of GPi. Inactivation of the GPi with muscimol produced movement deficits in a reach-grasp-retrieve task that can be summarized as follows: I) decreased peak wrist velocity during the reach to target; 2) decreased elbow and shoulder angular velocities, with elbow angular velocity relatively more impaired than shoulder angular velocity; resulting in 3) higher maximum vertical wrist and index finger positions at the apex of the reach; 4) prolonged latency from the end of the reach to the completion of grasp; and 5) less impairment of retrieval than reach, with inactivation at the majority of sites causing no impairment and some actually speeding up retrieval despite slow reaching. The results of this study show that reaching movements are impaired in a specific way after focal inactivation of GPi in previously normal monkeys. The slowing of the reach with normal (or fast) retrieval suggests that there is difficulty inhibiting the posture holding mechanisms that were active before the reach, but that assist the retrieval. The nature of the impairment supports the hypothesis that GPi lesions disrupt the ability to inhibit competing motor mechanisms to prevent them from interfering with desired voluntary movement.