suprachiasmatic nucleus

(redirected from Suprachiasmatic nuclei)

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.

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

suprachiasmatic nucleus

anatomic nucleus which innervates the pineal gland; thought to play a part in the management of circadian rhythms.
References in periodicals archive ?
Studies of the animals' brain activity showed that the constant light exposure reduced the normal rhythmic patterns in the brain's central circadian pacemaker of the suprachiasmatic nuclei (SCN) by 70 percent.
Suprachiasmatic nuclei receive light intensity-dependent signals [21], interpret them, then pass on signals to the pineal gland, which in response secretes more or less of the hormone melatonin.
Franken, "In Vivo imaging of the central and peripheral effects of sleep deprivation and suprachiasmatic nuclei lesion on PERIOD-2 protein in mice," Sleep, vol.
The circadian rhythm is generated in the suprachiasmatic nuclei (SCN) located in the hypothalamus in mammals.
In mammals, the circadian clock is controlled by an area of the brain called the suprachiasmatic nuclei (SCN) which pulls every cell in the body into the same biological rhythm.
1998) Light and circadian rhythmicity regulate MAP kinase activation in the suprachiasmatic nuclei.
2-5) In many animal models of insulin resistance, dopaminergic activity within the hypothalamus, particularly the normal daily circadian peak within the suprachiasmatic nuclei, is diminished.
Circadian rhythms are generated within the suprachiasmatic nuclei (SCNs) by the regulated expression of clock genes in discrete neuronal populations (1,9).
This clock is a collection of about 20,000 cells called the suprachiasmatic nuclei (SCN) located in the brain's hypothalamus.
4) The mammalian sleep/wake cycle is governed by the circadian clock as follows: (1) light is transferred from the retina via melanopsin in ganglion cells of the retinohypothalamic tract to (2) the 2 suprachiasmatic nuclei (SCN) in the hypothalamus, which interpret these data regarding day length and signal them to (3) the pineal gland, which secretes melatonin nocturnally for a duration corresponding to the habitual period of darkness (scotoperiod) experienced by the organism (5-8) (FIGURE 1).
Effects of lesions of the suprachiasmatic nuclei on paradoxical sleep and slow wave sleep circadian rhythms in the rat.