Roles of primate spinal interneurons in preparation and execution of voluntary hand movement
Roles of primate spinal interneurons in preparation and execution of voluntary hand movement
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DOI：
10.1016/s0165-0173(02)00188-1
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发表时间：
2002-10-01
影响因子：
--
通讯作者：
Votaw, S
中科院分区：
文献类型：
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作者：
Fetz, EE;Perlmutter, SI;Votaw, S
为了研究灵长类动物颈部中间神经元（INs）的贡献，准备和执行正常的自愿手部运动，我们调查了他们的活动和相关联系的肌肉在猴子执行跟踪任务。在斜坡和保持屈伸扭矩邻接手腕大多数任务相关的脊髓IN表现出一定的活动，在屈曲和伸展，在意想不到的对比，严格的单向活动的皮质肌神经元（CM）细胞和运动神经元。大多数神经元在这两个方向中的一个方向上增加了更多的活动;在其首选方向上的反应模式通常是强直性或相位强直性。在许多任务相关的神经内分泌系统中，肌电的峰电位触发平均值检测到肌肉活动的显著特征。前运动神经内分泌系统（PreM-INs）通过峰电位后易化或抑制以及触发峰电位后适当的起始潜伏期来识别。在皮层和红核区，PreM-INs的肌场比脊髓上PreM细胞的肌场小，很少涉及拮抗肌的相互作用。为了研究脊髓INs与不同肌肉协同作用的关系，记录了执行多向腕关节任务的猕猴的INs活动。猴子在屈曲/伸展、桡/尺偏、旋前/旋后产生等长扭矩，并执行共同收缩腕屈肌和伸肌的力量抓握。许多显示任务调制活动的IN在这个多方向空间中具有首选方向，通常具有广泛的调谐激活。在执行指令延迟任务的猴子中揭示了脊髓内神经在准备自愿运动中的作用。在一个短暂的视觉提示和一个去信号之间的延迟期间，三分之一的测试的IN显示出显着的延迟调制（SDM）的发射率相对于预提示率。在随后的有效扭矩期间，传感和诊断模块的响应通常与仪表板的响应不同。在猴子指示的视觉或本体感受的线索，延迟期活动的许多INs是类似的视觉和扰动试验，虽然其他INs表现出不同的SDM视觉和本体感受的线索试验。这些结果表明，在运动准备的最早阶段，脊髓内神经与皮质有关。对INs的感觉输入可以在对扭矩脉冲的瞬时响应中被识别，其显示出两种主要模式，与来自皮肤或本体感受器的输入一致。我们还研究了任务依赖性调制的神经反应的外周输入在猴子执行手腕弯曲/伸展运动中的视觉提示指示延迟任务。通过袖状电极电刺激桡浅神经诱发的单突触反应在动态运动阶段被抑制或消除。由于任务相关的活动的INs增加在同一时间，抑制介导的突触前，而不是突触后抑制。这些观察结果表明，在正常的行为条件下，许多脊髓神经元的响应特性与以前记录的行为动物的皮层神经元。(C)2002 Elsevier Science B. V.保留所有权利。
To study the contribution of primate cervical interneurons (INs) to preparation and execution of normal voluntary hand movement we investigated their activity and correlational linkages to muscles in monkeys performing tracking tasks. During ramp-and-hold flexion-extension torques abut the wrist most task-related spinal INs exhibited some activity during both flexion and extension, in unexpected contrast to the strictly unidirectional activity of corticomotoneuronal (CM) cells and motoneurons. Most INs increased their activity more in one of these two directions; response patterns in their preferred direction were typically tonic or phasic-tonic. Spike-triggered averages of EMG detected significant features in muscle activity for many task-related INs. Premotor INs (PreM-INs) were identified by post-spike facilitation or suppression with appropriate onset latencies after the trigger spike. Muscle fields of PreM-INs were smaller than those of supraspinal PreM cells in cortex and red nucleus, and rarely involved reciprocal effects on antagonist muscles. To investigate the relation of spinal INs to a repertoire of different muscle synergies, activity of INs was recorded from a macaque performing a multidirectional wrist task. The monkey generated isometric torques in flexion/extension, radial/ulnar deviation, pronation/supination, and executed a power grip that co-contracted wrist flexor and extensor muscles. Many INs showing task-modulated activity had preferred directions in this multidirectional space, typically with broadly tuned activation. The role of spinal INs in preparation for voluntary movement was revealed in monkeys performing instructed delay tasks. During the delay between a transient visual cue and a go signal a third of the tested INs showed significant delay modulation (SDM) of firing rate relative to the pre-cue rate. The SDM responses often differed from the INs' responses during the subsequent active torque period. In a monkey instructed by either visual or proprioceptive cues the delay period activity for many INs was similar in visual and perturbation trials, although other INs exhibited different SDM for visually and proprioceptively cued trials. These results suggest that spinal INs are involved, with cortex, in the earliest stages of movement preparation. The sensory input to INs could be identified in transient responses to the torque pulse, which showed two predominant patterns, consistent with inputs from cutaneous or proprioceptive receptors. We also investigated the task-dependent modulation of neural responses to peripheral input in a monkey performing wrist flexion/extension movements in a visually cued instructed delay task. Monosynaptic responses evoked by electrical stimulation of the superficial radial nerve through a cuff electrode were suppressed or abolished during the dynamic movement phase. Since task-related activity of the INs increased at the same time, the suppression was mediated by presynaptic rather than postsynaptic inhibition. These observations indicate that under normal behavioral conditions many spinal INs have response properties comparable to those previously documented for cortical neurons in behaving animals. (C) 2002 Elsevier Science B.V. All rights reserved.