Cranial nerve nucleus
（重定向自Cranial nerve nuclei）
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![Micrograph of the posterior portion of the open part of the medulla oblongata, showing the fourth ventricle (top of image) and the hypoglossal nucleus (medial - left of image) and the dorsal motor nucleus of the vagus nerve (lateral - right of image). H&E-LFB stain.](/Images/godic/202501/06/Medulla_oblongata_-_posterior_-_low_mag5655.jpg")
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A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with. All the nuclei except that of the trochlear nerve (CN IV) supply nerves of the same side of the body.