FUNCTIONAL ORGANIZATION OF CERVICAL SPINAL INTERNEURONS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 为了研究5-羟色胺对行为猴脊髓神经元放电特性的影响，我们完成了数据收集。新的数据证实了我们前几年在其他猴子身上的发现。5-羟色胺和5-羟色胺受体拮抗剂甲基丝氨酸应用于细胞外记录的神经元，用细胞外离子导入电极。5-羟色胺能显著增加脊髓神经元的整体活性。一小部分人在5-羟色胺离子导入后表现出放电减少。甲基色胺对这些神经元中的大多数都有相反的作用。其余神经元既不受5-羟色胺的影响，也不受其拮抗剂的影响。在应用5-羟色胺和5-羟色胺拮抗剂前后，测定多维腕部运动中C6-T1节段神经元的定向调谐。对于大多数神经元，阻断抑制对神经元的定向调谐影响不大。这些结果表明，5-羟色胺在调节许多脊髓神经元的兴奋性方面起着重要作用，但不会影响手腕不同方向运动的空间调谐。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Data collection was completed for our study of the effects of serotonin on the firing properties of neurons in the spinal cord of behaving monkeys. New data confirm our findings in other monkeys from previous years. Serotonin and the serotonin receptor antagonist methysergide were applied to extracellularly recorded neurons with a combined extracellular, iontophoresis electrode. Serotonin causes overall increase in activity of a significant percentage of spinal neurons. A small percentage exhibit decreased firing after iontophoresis of serotonin. Methysergide has the opposite effect for most of these neurons. The remaining neurons are not affected by either serotonin or its antagonist. The directional tuning of neurons in the C6-T1 segments was determined for multi-dimensional wrist movements before and after the iontophoretic application of serotonin and serotonin antagonists. Block of inhibition had little effect on the neurons' directional tuning for the majority of neurons. These results suggest that serotonin plays an important role in regulating excitability for many spinal neurons but does not affect spatial tuning for wrist movements in different directions.