FUNCTION OF THE EFFERENT VESTIBULAR SYSTEM

前庭器官具有丰富的传出神经支配，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。有三个具体目标：1）在巴比妥酸盐麻醉的灰鼠上，观察不同传出成分的电激活对几个传入成分的影响。这个问题最初是在大约20年前调查的。有必要更新的结果，考虑到最近的研究结果的组织传入和传出通路，最近的建议，EVS刺激可能有更多的异质性影响传入增益比怀疑。这项研究提供了必要的背景信息EVS的功能。2)通过比较急性和慢性消除传出神经支配或对侧迷路对传入放电的影响，研究潜在的长期或营养传出影响。神经活性肽和代谢营养型受体的存在，以及对电刺激的反应的某些特征表明EVS产生了这样的影响，但这个问题以前没有得到解决。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。记录将从前庭神经传入神经和脑干内的传出神经元在警觉的松鼠猴自由移动他们的头在一个水平面。对于这两组神经元，将比较对主动和被动头部运动的反应。传出神经从颈部、其他本体感受器或几个前庭器官获得输入的可能性将被探讨。前庭输入EVS的一些信息最好在急性准备中获得;这些实验将在去大脑的灰鼠中进行。

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.