The fastigial nucleus or nucleus fastigii refers specifically to the concentration of gray matter nearest to the middle line at the anterior end of the superior vermis, and immediately over the roof of the fourth ventricle, from which it is separated by a thin layer of white matter. It is smaller than the nucleus dentatus, but somewhat larger than the nucleus emboliformis and nucleus globosus, the other two independent centers of gray matter in the cerebellum. The fastigial nucleus is the smallest in size, with the dentate being the largest and the interposed being intermediate in size. Although it is one dense mass, it is made up of two sections: the rostral fastigial nucleus and the caudal fastigial nucleus.
The fastigial nucleus receives its afferent input from the vermis. Most of its efferent connections travel via the inferior cerebellar peduncle to the vestibular nuclei, which is located at the junction of the pons and the medulla oblongata.
The fastigial nucleus contains excitatory axons which project beyond the cerebellum, unlike the Purkinje cells that convey the purely inhibitory output of the cerebellar cortex. The likely neurotransmitters of the excitatory fastigial nucleus axons are glutamate and aspartate.
The Purkinje cells of the cerbellar cortex project into the deep cerebellar nuclei and inhibit the excitatory output system.
Rostral Fastigial Nucleus
The rostral fastigial nucleus (rFN) is related to vestibular system. It receives input from the vestibular nuclei and contributes to vestibular neuronal activity. The rFN interprets body motion and places it on spatial planes to estimate the movement of the body through space. It deals with antigravity muscle groups and other synergies involved with standing and walking.
Caudal Fastigial Nucleus
The caudal fastigial nucleus (cFN) is related to saccadic eye movements. The Purkinje cell output from the oculomotor vermis relays through the cFN, where neurons directly related to saccadic eye movements are located.
This article incorporates text from a public domain edition of Gray's Anatomy.