Medial parabrachial nucleus

The parabrachial nuclei, also known as the parabrachial complex, are a group of nuclei in the dorsolateral pons that surrounds the superior cerebellar peduncle as it enters the brainstem from the cerebellum. They are named from the Latin term for the superior cerebellar peduncle, the brachium conjunctivum. In the human brain, the expansion of the superior cerebellar peduncle expands the parabrachial nuclei, which form a thin strip of grey matter over most of the peduncle. The parabrachial nuclei are typically divided along the lines suggested by Baxter and Olszewski in humans, into a medial parabrachial nucleus and lateral parabrachial nucleus. These have in turn been subdivided into a dozen subnuclei: the superior, dorsal, ventral, internal, external and extreme lateral subnuclei; the lateral crescent and subparabrachial nucleus (Kolliker-Fuse nucleus) along the ventrolateral margin of the lateral parabrachial complex; and the medial and external medial subnucleiThe main parabrachial nuclei are the medial parabrachial nucleus, the lateral parabrachial nucleus and the subparabrachial nucleus.Many subsets of neurons in the parabrachial complex that target specific forebrain or brainstem cell groups contain specific neuropeptides, and appear to carry out distinct functions. For example, a population of neurons in the external lateral parabrachial subnucleus that contain the neurotransmitter calcitonin gene-related peptide (CGRP) appears to be critical for relaying information about hypoxia or hypercapnia (e.g., if one is being suffocated during sleep, such as by sleep apnea) to forebrain sites to wake up the brain, and prevent asphyxia.