part of part of periventricular zone of hypothalamus hypothalamic nucleus circular nucleus of antherior hypothalamic nucleus UBERON:0035596 NC neuronames:1853 circular nucleus A group of cells located in the central part of the anterior hypothalamic nucleus in the anterior hypothalamic region of the rat ( Swanson-2004 ) and the mouse ( Paxinos-2001 ). Functionally it belongs to the magnocellular neuroendocrine cell groups of the subcortical motor system ( Swanson-2004 ). group of magnocellular elements arranged in a ring around a capillary bed. The cells are predominantly monopolar, tightly packed, and are flattened at the outer border of the ring. The entire nucleus is surrounded or encapsulated by myelinated fibers, hypothesized to be an osmoreceptor[PMID:974791] nucleus circularis MBA:432