Connectivity-Based Subdivisions of the Human Right "Temporoparietal Junction Area": Evidence for Different Areas Participating in Different Cortical Networks

TLDR

The temporoparietal junction’s role in attention reorientation and social cognition remains controversial, with debate over whether it is a single region or multiple functionally distinct subregions. This study aimed to determine whether TPJ is a unitary area with heterogeneous connectivity or a conglomerate of distinct regions by examining its structural and functional connectivity. Diffusion‑weighted imaging tractography parcellated TPJ into three regions, and resting‑state functional connectivity mapped each region’s participation in cortical networks. The dorsal cluster linked to lateral anterior prefrontal cortex, the ventral cluster to ventral prefrontal cortex and anterior insula, and the posterior cluster to posterior cingulate, temporal pole, and anterior medial prefrontal cortex, demonstrating TPJ’s subdivision based on connectivity.

Abstract

Controversy surrounds the role of the temporoparietal junction (TPJ) area of the human brain. Although TPJ has been implicated both in reorienting of attention and social cognition, it is still unclear whether these functions have the same neural basis. Indeed, whether TPJ is a precisely identifiable cortical region or a cluster of subregions with separate functions is still a matter of debate. Here, we examined the structural and functional connectivity of TPJ, testing whether TPJ is a unitary area with a heterogeneous functional connectivity profile or a conglomerate of regions with distinctive connectivity. Diffusion-weighted imaging tractrography–based parcellation identified 3 separate regions in TPJ. Resting-state functional connectivity was then used to establish which cortical networks each of these subregions participates in. A dorsal cluster in the middle part of the inferior parietal lobule showed resting-state functional connectivity with, among other areas, lateral anterior prefrontal cortex. Ventrally, an anterior TPJ cluster interacted with ventral prefrontal cortex and anterior insula, while a posterior TPJ cluster interacted with posterior cingulate, temporal pole, and anterior medial prefrontal cortex. These results indicate that TPJ can be subdivided into subregions on the basis of its structural and functional connectivity.