Fetz E E
Department of Physiology and Biophysics and Regional Primate Research Center, University of Washington, Seattle, WA 98195-7290, USA.
Pain. 1999 Aug;Suppl 6:S55-S60. doi: 10.1016/S0304-3959(99)00138-4.
This paper reviews studies on spinal interneurons in awake, behaving monkeys inspired by the work of Prof Patrick D. Wall. Early studies documented the sensory responses of spinal interneurons in unanesthetized monkeys to natural cutaneous and proprioceptive stimulation. More recently, cervical interneurons were documented in monkeys performing an active step-tracking task. During alternating wrist movements, most task-related interneurons showed bidirectional activity, firing during both flexion and extension (in surprising contrast to the unidirectional activity of muscles and corticomotoneuronal cells). Premotor interneurons were identified by post-spike effects in spike-triggered averages of forelimb muscle activity. The cells' post-spike effects were generally congruent with their activity in their preferred direction, although many fired during components of movement when their output effects would seem inappropriate. In an instructed delay period task many interneurons showed preparatory delay period activity, much like cortical neurons. Other studies tested the excitability of corticospinal axons to electrical stimulation and demonstrated both post-spike and task-related modulations in excitability. Together, these studies suggest that many behavioral functions of spinal interneurons remain to be revealed by recording their activity in awake, behaving animals.
本文回顾了受帕特里克·D·沃尔教授的研究启发，对清醒状态下行为猴脊髓中间神经元的研究。早期研究记录了未麻醉猴子脊髓中间神经元对自然皮肤和本体感觉刺激的感觉反应。最近，在执行主动步追踪任务的猴子身上记录到了颈段中间神经元。在交替手腕运动期间，大多数与任务相关的中间神经元表现出双向活动，在屈曲和伸展时均放电（这与肌肉和皮质运动神经元细胞的单向活动形成惊人对比）。通过前肢肌肉活动的触发尖峰平均值中的尖峰后效应识别出运动前中间神经元。这些细胞的尖峰后效应通常与其在偏好方向上的活动一致，尽管许多细胞在运动成分期间放电时其输出效应似乎并不合适。在指令延迟期任务中，许多中间神经元表现出预备延迟期活动，很像皮质神经元。其他研究测试了皮质脊髓轴突对电刺激的兴奋性，并证明了兴奋性的尖峰后和与任务相关的调制。总之，这些研究表明，通过在清醒、行为动物中记录脊髓中间神经元的活动，许多行为功能仍有待揭示。
