part of part of supraoptic nucleus hypothalamic nucleus tuberal supraoptic nucleus retrochiasmatic subdivision NLXANAT:20090311 tuberal supraoptic nucleus UBERON:0024079 Posterior division of the supraoptic nucleus, formed by the ascension of the optic tract splitting the nucleus into two regions. The tuberal SON lies along the posterior tuber cinereum of the hypothalamus. In some species, some neurons lie under the optic chiasm.