Lighting cycles synchronize (entrain) mammalian circadian rhythms by altering activity of cells in the suprachiasmatic nucleus (SCN) hypothalamus, a pacemaker. Exposure hamsters and rats to light pulses at those phases rhythm during which can shift caused increased immunoreactivity for product immediate-early gene c- fos region SCN that receives retinal fibers. Light also messenger RNA Fos protein NGFI-A rat SCN. Similar increases mRNA were seen hamsters. Thus this portion undergo...

Objective To examine the impact of sleep duration on emotional functioning and cognitive performance in children. Methods 32 children (8–12 years) wore actigraphs for 3 weeks. Following a week typical sleep, each child was randomly assigned to go bed 1 hr earlier 4 nights (Long Sleep) or later (Short relative their bedtime. Each then completed opposite condition. After week, were assessed using objective subjective measures. Results revealed impaired Short- Long-Sleep condition measures...

We have investigated the effects of destruction geniculo-hypothalamic tract (GHT) on circadian system golden hamsters. In first experiment, intact hamsters were housed in constant darkness, and phase shifts running-wheel activity rhythms assessed following 15-min light pulses administered at time (CT) 12 (defined as beginning activity), CT 14, 18, 20. Responses to same CTs then reassessed after GHT lesions. Hamsters with complete lesions showed decreases advances caused by 18 Phase delays...

We studied the influence on circadian rhythms of peptides that have been reported to be colocalized in suprachiasmatic nucleus (SCN) neurons. Gastrin-releasing peptide (GRP1-27), histidine isoleucine (PHI), and vasoactive intestinal polypeptide (VIP) were microinjected into region Syrian hamsters free running under three different constant lighting conditions. All injections caused phase-dependent phase shifts hamster locomotor activity which unaffected by GRP1-27 (150 pmol) large delays...

People with Alzheimer' s disease (AD) commonly complain of sleep disturbances, which are seen in a wide variety conditions that become more common late life. It is not known whether sleep-related symptoms associated AD independently their association other illnesses. Secondary analyses measures collected through the Survey Health, Ageing and Retirement Europe (SHARE; i.e., sleeping problems, fatigue, taking medication, trouble or change pattern) were conducted on those who reported absence...

Lesions of the suprachiasmatic nuclei (SCN) golden hamsters prevented testicular regression ordinarily observed in short photoperiods or after peripheral enucleation. These lesions also induced regrowth whose testes had previously been regressed by absence adequate photostimulation. Interruption primary optic tracts just caudal to chiasm did not prevent photoperiods. We hypothesize that responses photoperiod are mediated retinohypothalamic tract, which projects SCN, and SCN turn control...

In mammals, the suprachiasmatic nucleus is responsible for generation of most circadian rhythms and their entrainment to environmental cues. Cholinergic agents can alter rhythm phase, fibres immunoreactive choline acetyltransferase, biosynthetic enzyme acetylcholine, are present in nucleus. Since there no cholinergic somata nucleus, these must represent terminals neurons whose cell bodies located elsewhere brain. This study was aimed at locating that project by retrograde anterograde...

The integrity of the suprachiasmatic nuclei (SCN) hypothalamus is essential to expression normal circadian rhythms in rodents. Electrical stimulation SCN caused phase shifts and period changes freerunning feeding rats activity hamsters. response curve for appears parallel that light pulses. These findings strengthen hypothesis derived from lesion studies are dominant light-entrained oscillators rodent system.