The medial parietal cortex (MPC) is a region of cortex about which very little is known. The MPC is located on the medial surface of the brain and is distinguished rostrally by the medial extension of the central sulcus, caudally by the medial parieto occipital sulcus and ventrally by the variable splenial sulcus. It is comprised of several cytoarchitectural regions including:​ the lower body sensory representation of areas 3, 1, 2 and 5, medial area 7, and area 31, the latter two areas comprising the primary regions of interest in this study, collectively known as the precuneus.

Due to limited connectional studies and diverse functional imaging findings of the MPC, this region is often descriptively and functionally combined with the lateral parietal areas and adjacent posterior cingulate and retrosplenial cortices. Consequently, the functions and neural systems of the MPC remain unclear. The ambiguity of the MPC is further complicated by cytoarchitectural and histological studies that characterize areas of the MPC based on existing classifications and a lack of clear cytoarchitectural or phenotypic boundaries distinguishing the MPC from the adjacent medial cortices.

Using modern retrograde and anterograde neuroanatomical tracers we injected the MPC, as well as adjacent cortical areas and lateral parietal cortex, in the macaque. The neural tissue was subsequently analyzed to determine the neural systems to which the MPC belongs and its cytoarchitectural and phenotypic characteristics.

Based on the belief that the function of an area is determined by the neural circuits to which it belongs, the connectional data of the MPC with the cortical telencephalon and diencephalon in the macaque presented herein argues that the neural systems of the MPC are functionally distinct from the lateral parietal areas and adjacent medial cortices. Furthermore, the cytoarchitectural and phenotypic properties of the MPC are thoroughly described and differentiated from adjacent cortices.

These neural systems of the MPC are correlated to relevant functional imaging and behavioral studies.