They are in the Melanesia subregion and bioregion of Oceania. The Deep South is a cultural and geographic subregion in the Southern United States. The volcanic archipelago is physiographically and ethnologically part of the Polynesian subregion of Oceania. Dallas is part of the Deep South cultural and geographic subregion. The function of NMDA receptors varies according to the subregion of the hippocampus. The Ellice Islands are recognised as part of the Polynesia subregion of Oceania. The second subregion, the parahippocampal cortex, is involved in source information. Jasper is situated in the Deep East Texas subregion, about northeast of Houston. Meinig calls the third subregion "El Paso, Tucson, and the Southern Borderlands". The fourth subregion Meinig calls the "Northern Corridor and Navajolands". The genu subregion is larger in males. The boundaries of the subregion depends on the exact criteria being used. It is a subregion of the Western United States. The main town in the Upper Hunter Valley subregion is Muswellbrook. It is part of the Melanesia subregion.