FUNCTION OF THE EFFERENT VESTIBULAR SYSTEM

前庭器官具有丰富的传出神经，起源于脑干。本研究的长期目标是了解传出前庭系统(EVS)在前庭信息处理中的功能。本研究有三个具体目的：1)在巴比妥钠麻醉的灰鼠模型上，观察不同传出通路电刺激对不同传入通路的影响。这个问题最初是在近20年前调查的。有必要更新结果，考虑到关于组织传入和传出通路的最新研究结果，因为最近的一项研究表明，电刺激电刺激对传入获得的影响可能比人们怀疑的更多。这项研究提供了有关电动汽车功能的基本背景信息。2)通过比较急性和慢性对消除传出神经或对侧迷路的传入放电的影响，研究潜在的长期或营养性传出影响。神经活性多肽和代谢性受体的存在，以及对电刺激的反应的某些特征表明EVS具有这种影响，但这个问题以前没有解决过。3)确定导致传出神经元放电和传出介导的传入传递变化的条件。记录将来自前庭神经传入和脑干内的传出神经元，这些神经元是警觉的松鼠猴子，可以在水平面上自由移动它们的头。我们将比较两组神经元对主动和被动头部运动的反应。我们将探讨传出神经从颈部、其他本体感受器或几个前庭器官传入的可能性。一些关于前庭输入到电动汽车的信息最好是在急性准备中获得的；这些实验将在去大脑的龙猫身上进行。

Vestibular organs are provided with a rich efferent innervation, originating in the brain stem. The long-term objective of this study is to understand the function of the efferent vestibular system (EVS) in the processing of vestibular information. There are three specific aims: 1) To determine the effects of electrical activation of different efferent contingents on the several afferent groups in the barbiturate- anesthetized chinchilla. The problem was originally investigated almost 20 years ago. There is a need to update results by taking into account recent findings on the organization on afferent and efferent pathways, as a recent suggestions that EVS stimulation may have more heterogeneous influence on afferent gain than had been suspected. This study provides essential background information concerning the function of the EVS. 2) To study potential long-term or trophic efferent influences by comparing the acute and chronic effects on afferent discharge on eliminating the efferent innervation or the contralateral labyrinth. The presence of neuroactive peptides and metabotrophic receptors, as well as certain features of the response to electrical stimulation suggests that the EVS exerts such an influence, yet the problem has not been previously addressed. 3) To determine the conditions leading to the discharge of efferent neurons and to efferent-mediated changes in afferent transmission. Recordings will be made from vestibular-nerve afferents and from efferent neurons within the brain stem in alert squirrel monkeys free to move their heads in a horizontal plane. For both groups of neurons, responses to active and passive head movements will be compared. The possibility that efferents get inputs from the neck, from other proprioceptors or from several vestibular organs will be explored. Some information on vestibular inputs to the EVS are best obtained in acute preparations; these experiments will be done in decerebrate chinchillas.