| Term: | hindbrain primary motor neuron |
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| Note: | This page represents a term created by the combination ("post-composition") of two ontology terms. For more information on the individual terms, click the hyperlinked name. |
| Name: | hindbrain |
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| Synonyms: | rhombencephalon |
| Definition: | The most posterior of the three principal regions of the brain. In mammals and birds the hindbrain is divided into a rostral metencephalon and a caudal myelencephalon. In zebrafish, with the exception of the cerebellum, the ventral remainder of the metencephalon can be separated only arbitrarily from the more caudal myelencephalic portion of the medulla oblongata and thus these are not distinguished here. From Neuroanatomy of the Zebrafish Brain. |
| Ontology: | Anatomy Ontology [ZFA:0000029] |
| Name: | primary motor neuron |
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| Synonyms: | primary motoneuron |
| Definition: | Motor neurons that arise during the first day of development. Primary motoneurons have larger diameter cell bodies and axons than secondary motoneurons and are positioned more dorsally and medially than secondary motoneurons. Primary motoneurons are present in a single bilateral pair of clusters in each spinal segment and innervate axial muscle fibers in the corresponding pair of myotomes. Axons make a conspicuous loop around the Mauthner axon before entering the ventral root. |
| Ontology: | Anatomy Ontology [ZFA:0009244] |