SEGMENTAL CONTROL OF NECK MUSCLES

这个项目的长期目标是了解脊髓是如何 在脊髓的不同区域适应不同的机制以辅助 不同的动作或功能。这将由以下人员研究 检查颈部节段内的组织，以寻找参与其中的肌肉 头部运动。结果将与广博的知识进行比较 后肢节段的脊柱机制，以及少见的 对其他地区的组织情况的观察。 实验将集中于群体的反射和突触前动作 I肌肉传入(Ia来自纺锤体，Ib来自高尔基肌腱器官)，自 现有的最详细的对比观察涉及以下几点 行为。然而，关于其他传入神经活动的信息(来自肌肉 或皮肤)，以及其他机制(复发效应)，将在 在实验过程中，扩展分段控制的知识 头部的运动。据推测，突触前动作(即 施加于其他传入的)帮助反射动作产生特定的 动静。这将意味着特定的突触前动作模式 应该匹配特定的反射动作模式，如下面所示 描述了神经元子系统的特性和数量 行为。这也意味着突触前和反射动作应该 在脊髓的不同区域一起变化，服务于不同的 动静。 这些实验将在麻醉的猫身上进行。细胞内和 轴突内记录将用于研究发生了什么动作： 尤其是Ib反射、Ia相互抑制和Ia 模仿Ib反射的反射出现在颈部节段，如 后肢。将研究突触前活动的分布； 对Ia增效作用的研究得到了扩展。电刺激的种类 神经，空间促进方法，以及选择性激活Ia和 IB传入，将被用来描述潜在的神经系统， 关于特定目标的收敛输入模式的术语。分配 的影响，所描述的神经系统，将被检查 不同脊椎机制的平行或不对称的动作。 节段性控制的变化将与节段控制的变化进行比较 下降控制。通过检查反射和反射的区域适应 控制它们的脊椎机制，该项目将提供进一步的 洞察动作和姿势的正常产生方式，以及 控制住了。

The long-term objective of this project is to understand how spinal cord mechanisms are adapted in different regions of the spinal cord to subserve different kinds of movement or functions. This will be studied by examining organization within the neck segments, for muscles involved in head movements. The results will be compared to the extensive knowledge of spinal mechanisms in the hindlimb segments, as well as to the scarcer observations on organization in other regions. The experiments will focus on the reflexes and presynaptic actions of group I muscle afferents (Ia from spindles, Ib from Golgi tendon organs), since the most detailed comparative observations available concern these actions. However, information on actions of other afferents (from muscle or skin), and on other mechanisms (recurrent effects), will be obtained in the course of the experiments, to extend knowledge of the segmental control of head movements. It is hypothesized that presynaptic actions (which are exerted on other afferents) assist reflex actions in producing specific movements. This would mean that specific patterns of presynaptic actions should match specific patterns of reflex actions, as would be revealed by describing the properties and numbers of neuronal subsystems mediating the actions. It would also mean that presynaptic and reflex actions should vary together in different regions of the spinal cord, to serve different movements. The experiments will be performed on anesthetized cats. Intracellular and intraaxonal recording will be used to study what actions occur: particularly, whether Ib reflexes, Ia reciprocal inhibition, and the Ia reflexes mimicking Ib reflexes occur in the neck segments as in the hindlimb. The distribution of presynaptic actions will be investigated; the study of Ia synergisms extended. Electrical stimulation of a variety of nerves, spatial facilitation methods, and selective activation of Ia and Ib afferents, will be used to characterize underlying neuronal systems, in terms of patterns of convergent inputs for specific targets. Distributions of effects, the neuronal systems described, will be examined for parallelisms or assymetries of actions of different spinal mechanisms. Variations in segmental control will be compared to variations in descending control. By examining regional adaptation of reflexes and spinal mechanism controlling them, this project will provide further insight into the way movements and posture are normally produced and controlled.