| neural plate | <embryology> A region of embryonic ectodermal cells, called neuroectoderm, that lie directly above the notochord. During neurulation, they change shape, so as to produce an infolding of the neural plate (the neural fold) that then seals to form the neural tube. (04 Jul 1999) |
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| neural retina | <embryology> Layer of nerve cells in the retina, embryologically part of the brain. The incoming light passes through nerve fibres and intermediary nerve cells of the neural retina, before encountering the light sensitive rods and cones at the interface between neural retina and the pigmented retinal epithelium. (04 Jul 1999) |
| neural segment | Alternate swellings and constrictions seen along the neuraxis at early stages of neural tube development, thought to be evidence of intrinsic segmentation in the CNS. Neuromeres or segments in the hindbrain region are called rhombomeres and have been shown to be lineage restriction units, each constructing a defined piece of hindbrain. (18 Nov 1997) |
| neural spine | The middle point of the neural arch of the typical vertebra, represented by the spinous process. (05 Mar 2000) |
| neural tube | <embryology> The progenitor of the central nervous system. See: neural plate, neurulation. (18 Nov 1997) |
| neural tube defect | <neurology, paediatrics> Abnormal development during embryonic life of the neural tube producing congenital malformations of the nervous system due to closure failure of the neural tube. The structure gives rise to the central nervous system (the brain and spinal cord), and failure to close results in anencephaly (absence of the cranial vault and absence of most or all of the cerebral hemispheres of the brain) and spina bifida or meningomyelocele (open spina with exposure and protusion of the spinal cord). The risk of neuroal tube defects can be decreased by the mother taking folic acid during pregnancy. (04 Jul 1999) |
| dorsal plate of neural tube | The thin layer of the embryonic neural tube connecting the alar plate's dorsally. Synonym: dorsal plate of neural tube. (05 Mar 2000) |
| dorsolateral plate of neural tube | The dorsal division of the lateral walls of the neural tube in the embryo; it gives rise to neurons relaying afferent impulses to higher centres; in the adult such neurons compose the sensory nuclei of the spinal cord and brainstem. Synonym: lamina alaris, alar plate of neural tube, dorsolateral plate of neural tube, lamina dorsalis, wing plate. (05 Mar 2000) |