三叉神经中脑核与小脑的联系

THE CEREBELLAR CONNECTIONS OF THE MESENCEPHALIC NUCLEUS OF THE TRIGEMINUS(RÉSUMÉ)

我观察了哺乳纲主要各目的代表动物的脑切片,认定广义的三叉神经中脑核由三个路线连接小脑。这群感觉细胞通过前髓帆到达小脑基部、第四脑室的顶板,顶核以及蚓小结的皮貭。在上端,中脑核细胞深在第四脑室的旁壁;它们的中枢突起靠中央灰貭外缘纵行向后伸展。有些细胞可随着蓝斑、也可能连同结合臂进入小脑。中脑核主部的纤维经脑室旁壁向背侧弯行,直入顶核和小脑的髓貭;也有少数细胞沿此路綫散在。中脑核细胞可经前庭内侧、外侧和(可能)上核散入小脑,特是齿状核。除三叉神经外,中脑核细胞也连接动眼、滑车、外展、面、舌咽和迷走神经,它们的运动(和感觉)核团,以及延髓的网状结构。据此,“三叉神经中脑核”是一个误称。它不专属三叉神经,也不局于中脑地区。它实是散处脑干内部的一群一级的感觉细胞。这一系感觉细胞传导自受的和外受的神经冲动,这起于咀咬肌和连属的皮肤和粘膜。它们连接小脑,供给它必要的求心资料,以便它协调正在执行的进食动作。此外,它们似也调节眼肌、面肌、咽喉肌、甚至颈肌的运动。小脑皮质上有头颈部的自受和外受系的投射地区;本文阐述的事实给这个生理的发现若干形态的根据。

Having examined the sectioned and stained brain material of the representatives ofthe main orders of the mammalian class,I recognize three routes by which the mesen-cephalic nucleus of the trigeminal nerve in the broad sense is connected to the cerebellum.Through the anterior medullary velum,these sensory ganglionic cells attain to thecerebellar basis,the roof plate of the fourth ventricle,the fastigial nucleus and the cortexof the nodulus.Rostrally the cells of this nucleus are deeply stationed in the side-wall of the fourthventricle;their central processes course posteriorly along the outer margin of the centralgray matter.The fibers from the main nucleus sweep dorsally around into the fastigialnucleus and the cerebellar medulla;and a few sensory cells strewn along this route.Suchsensory cells may also migrate into the cerebellum in company with the nucleus coeruleusand possibly also with the brachium conjunctivum.Through the medial,lateral and possibly superior vestibular nuclei the cells of themesencephalic nucleus are scattered along to the cerebellum,its dentate nucleus in parti-cular.Besides the trigeminal nerve,the mesencephalic nucleus is also related to the oculo-motor,trochlear,abducent,facial,glossopharyngeal and vagal nerves,their motor nucleiand the reticular formation of the medulla oblongata.It is neither affiliated specifically tothe trigeminus nor confined to the midbrain.The"mesencephalic nucleus of the trige-minus"is thus a long misnomer.Collectively it is a rarefied group of primary sensorycells oddly inclosed in the central nervous system.These centrally situated sensory cells conduct proprioceptive and exteroceptive impu-lses chiefly from the jaw muscles and the associated skin and mucous membrane.Theirconnections with the cerebellum afford the latter with the necessary afferent data for itscoordination of the feeding activity in progress.Besides,these sensory cells are appar-ently concerned also with the regulation of the movements of the eye,ear,nose,mouth,pharynx and larynx and possibly of the neck.There exist on the cerebellar cortex proprioceptive and exteroceptive projection fieldsfor the head region;this physiological finding gains some morphological support fromwhat has been elucidated in the present study.