Mapping Connectional Differences between Humans and Macaques in the Nucleus Accumbens Shell-Core Architecture

Abstract

1Two nucleus accumbens subregions, the shell and core, differ in the patterns whereby 2 they integrate signals from prefrontal and limbic areas of the brain. In this study, we 3 investigated whether the disproportionate volumetric differences of these brain areas, 4 particularly the prefrontal cortex, between humans and macaques are accompanied by 5 unique modifications of their macroscopic integrative connections with the shell and 6 core. More specifically, we characterized the tractographic connectivity profiles of the 7 human and macaque shell-core architecture and compared them between the two 8 species. To make the cross-species comparisons more viable, we used the same 9 whole-brain voxel-wise tractography-defined shell-like and core-like divisions in the 10 two species as seeds and delineated pairs of interspecies connectionally comparable 11 (ICC) target regions based on the similarity of the resting-state functional connectivity 12 profiles for the two species, and finally used these seeds and ICC targets to establish a 13 fingerprint-based common space for cross-species comparisons. Our results revealed 14 that dissimilar structural connectivity profiles were found in the prefrontal but not the 15 subcortical target group. We further localized this difference to specific targets to infer 16 possible functional modifications between the two species. 17

Fine-Grained Topography and Modularity of the Macaque Frontal Pole Cortex Revealed by Anatomical Connectivity Profiles

“…Exploring the modular structure of a community and the connectivity patterns of different functional networks is important for understanding brain mechanisms and evolution. Many neuroscientific studies [59][60][61] have revealed that the brain networks share important organizational principles in common, such as modularity, and that topological modules often comprise anatomically neighboring cortical areas. In addition, the modules of brain networks contain both unilateral and bilateral areas [62], and a community structure in the brain can be correlated with functionally localized regions, such as visual, auditory, and central modules [63].…”