parabrachial nucleus

In the human brain the parabrachial area forms a horseshoe-shaped strip of grey matter, and the parabrachial nucleus is a nucleus within it. The area comprises three named components: the Kolliker-Fuse nucleus, the lateral parabrachial nucleus, and the medial parabrachial nucleus. The horseshoe configuration describes how the grey matter wraps around neighbouring fibre systems at this level of the brainstem, and the tripartite subdivision is the basis on which parabrachial territory is mapped in descriptive neuroanatomy. The entry carries three subordinate structures in the anatomical hierarchy, matching those named divisions, so references to the parabrachial nucleus are best read as references to a group of adjacent nuclei rather than to a single homogeneous cell mass.