Cerebellum a variant of Guillain–Barré syndrome. The human cerebellum changes with age. These changes may differ from those of other parts of the brain. The cerebellum is the youngest brain region (and body part) in centenarians according to an epigenetic biomarker of tissue age known as epigenetic clock: it is about 15 years younger than expected in a centenarian. Further, gene expression patterns in the human cerebellum show less age-related alteration than that in the cerebral cortex. Some studies have reported reductions in numbers of cells or volume of tissue, but the amount of data relating to this question is not
Lateral hypothalamus neuropeptides orexin-A and orexin-B are the primary signaling neurochemicals in orexin neurons; pathway-specific neurochemicals include GABA, melanin-concentrating hormone, nociceptin, glucose, the dynorphin peptides, and the appetite-regulating peptide hormones leptin and ghrelin, among others. Notably, cannabinoid receptor 1 (CB1) is colocalized on orexinergic projection neurons in the lateral hypothalamus and many output structures, where the CB1 and orexin receptor 1 (OX1) receptors form the CB1–OX1 receptor heterodimer. The orexinergic projections from the lateral hypothalamus innervate the entirety of the remainder of the hypothalamus, with robust projections to the posterior hypothalamus, tuberomammillary nucleus (the histamine projection nucleus), the arcuate nucleus, and the