suprachiasmatic nucleus


anterior hypothalamic area

the rostral portion of the hypothalamus generally located internal to the region of the optic chiasm; contains the following nuclei: anterior hypothalamic nucleus [TA] (nucleus anterior hypothalami [TA]), anterior periventricular nucleus [TA] (nucleus periventricularis ventralis [TA]), interstitial nuclei of anterior hypothalamus [TA] (nuclei interstitiales hypothalami anteriores [TA]), lateral preoptic nucleus [TA] (nucleus preopticus lateralis [TA]), medial preoptic nucleus [TA] (nucleus preopticus medialis [TA]), median preoptic nucleus [TA] (nucleus preopticus medianus [TA]), paraventricular nucleus [TA] (nucleus paraventricularis hypothalami [TA]), periventricular preoptic nucleus [TA] (nucleus preopticus periventricularis [TA]), suprachiasmatic nucleus [TA] (nucleus suprachiasmaticus [TA]), and supraoptic nucleus [TA] (nucleus supraopticus [TA]). The latter cell group consists of dorsomedial, ventromedial, and dorsolateral parts.
See also: hypothalamus.
Synonym(s): area hypothalamica rostralis [TA], anterior hypothalamic region ☆

suprachiasmatic nucleus

A small hypothalamic nucleus lying at the base of the third ventricle, directly above the optic chiasm. This nucleus generates the brain's circadian rhythm. To entrain its rhythm with the natural day-night cycle, the nucleus is innervated by optic axons via the accessory optic tract; it also receives axons from the lateral geniculate nucleus of the thalamus, and serotonergic axons from the midbrain raphe nuclei. The suprachiasmatic nucleus sends most of its axons to the paraventricular nucleus of the hypothalamus. See also: nucleus