The paramedian reticular nucleus (in

Terminologia Anatomica ''Terminologia Anatomica'' (commonly abbreviated TA) is the international standard for human anatomy, human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology (FIPAT) a program of the Inter ...

, or paramedian medullary reticular group in NeuroNames) sends its connections to the spinal cord in a mostly ipsilateral manner, although there is some decussation. It projects to the

vermis The cerebellar vermis (from Latin ''vermis,'' "worm") is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior s ...

in the anterior lobe, the pyramis and the

uvula The uvula (: uvulas or uvulae), also known as the palatine uvula or staphyle, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fi ...

. The paramedian nucleus also projects to the contralateral PRN, the

gigantocellular nucleus The gigantocellular reticular nucleus (also magnocellular reticular nucleus) is the (efferent/motor) medial zone of the reticular formation of the caudal pons and rostral medulla oblongata. It consists of a substantial number of giant neurons, but ...

, and the nucleus ambiguous. The paramedian reticular formation is adjacent to the abducens (VI)nucleus in the pons and adjacent to the oculomotor nucleus(III) in the midbrain. The paramedian nucleus receives afferents mostly from the

fastigial nucleus The fastigial nucleus (roof nucleus-1) is located in each cerebellar hemisphere. It is one of the four paired deep cerebellar nuclei of the cerebellum. It is made up of two sections: the rostral fastigial nucleus and the caudal fastigial nucle ...

in the cerebellum and the cerebral cortex; however, the projections from the spinal cord are very sparse. The descending afferent connections come mostly from the frontal and parietal lobes; however the pontine reticular formation also sends projections to the paramedian reticular nucleus. There are also very sparse innervations from the

superior colliculus In neuroanatomy, the superior colliculus () is a structure lying on the tectum, roof of the mammalian midbrain. In non-mammalian vertebrates, the Homology (biology), homologous structure is known as the optic tectum or optic lobe. The adjective f ...

. Lesions in the paramedian reticular nucleus have been shown to cause a stereotyped increase in the random patterns of motion in rats.Lee EH, et al. Multiple inhibitory actions of the paramedian reticular nucleus—effects on blood pressure and motor activities in rats. Chin J Physiol. 1990;33(1):49–61. The paramedian nuclei on either side of the brain stem have been shown to mediate the horizontal

eye movements Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of i ...

on their

ipsilateral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

sides. It seems possible that the random motion patterns of the above rats were caused by an inability to mediate their horizontal eye movements.

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{{Authority control Medulla oblongata

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