Honrubia V, Suarez C, Kuruvilla A, Sitko S
Laryngoscope. 1985 Dec;95(12):1526-35. doi: 10.1288/00005537-198512000-00014.
A study was made of the projection patterns in the vestibular nuclei of primary afferent fibers innervating the crista of the anterior semicircular canal (ASC) of the bullfrog. Individual neurons were intracellularly recorded to characterize their spontaneous activity and injected with horseradish peroxidase to visualize their central and peripheral projections. A quantitative evaluation was made of the lengths of the central projections of primary afferents in the various vestibular nuclei and of the number of branch terminals and their precise locations in each of the major vestibular projection areas in the brain stem. The differences between the central projection patterns of the two types of primary afferent fibers were documented: the thick fibers with their irregular spontaneous activity and the thin fibers with their more regular spontaneous activity. Each neuron sends many terminals to various vestibular nuclei. The ventral part of the ventral nucleus receives the greatest number of terminals from fibers of all sizes. The medial nucleus receives terminals from the thin fibers only, while the reticular formation receives terminals exclusively from the thick fibers. All the vestibular nuclei receive innervation from ASC afferents, with considerable overlap in areas of innervation between fibers of different caliber. Differences were found between the thick and thin fibers in their locations, their patterns of branching, and the appearance of their terminal boutons. These anatomic characteristics are interpreted to represent physiologic differences in the production of reflexes by thick and thin neurons. It is also postulated that these different neurons play different roles in vestibular system function: thick neurons contribute to the maintenance of equilibrium during movement while thin neurons participate in the maintenance of posture and vestibular tonus.
对支配牛蛙前半规管嵴的初级传入纤维在前庭核中的投射模式进行了研究。对单个神经元进行细胞内记录以表征其自发活动，并注射辣根过氧化物酶以观察其中枢和外周投射。对不同前庭核中初级传入纤维的中枢投射长度、脑干各主要前庭投射区域中分支终末的数量及其精确位置进行了定量评估。记录了两种类型初级传入纤维的中枢投射模式之间的差异：具有不规则自发活动的粗纤维和具有更规则自发活动的细纤维。每个神经元向不同的前庭核发送许多终末。腹侧核的腹侧部分接收来自各种大小纤维的最多数量的终末。内侧核仅接收来自细纤维的终末，而网状结构仅接收来自粗纤维的终末。所有前庭核都接受前半规管传入纤维的支配，不同口径纤维的支配区域有相当大的重叠。在粗、细纤维的位置、分支模式和终末小体的外观方面发现了差异。这些解剖学特征被解释为代表粗、细神经元在产生反射方面的生理差异。还推测这些不同神经元在前庭系统功能中发挥不同作用：粗神经元有助于运动期间平衡的维持，而细神经元参与姿势和前庭紧张度的维持。
