Connectivity‐based parcellation: Critique and implications

Abstract

Regional specialization and functional integration are often viewed as two fundamental principles of human brain organization. They are closely intertwined because each functionally specialized brain region is probably characterized by a distinct set of long-range connections. This notion has prompted the quickly developing family of connectivity-based parcellation (CBP) methods in neuroimaging research. CBP assumes that there is a latent structure of parcels in a region of interest (ROI). First, connectivity strengths are computed to other parts of the brain for each voxel/vertex within the ROI. These features are then used to identify functionally distinct groups of ROI voxels/vertices. CBP enjoys increasing popularity for the in-vivo mapping of regional specialization in the human brain. Due to the requirements of different applications and datasets, CBP has diverged into a heterogeneous family of methods. This broad overview critically discusses the current state as well as the commonalities and idiosyncrasies of the main CBP methods. We target frequent concerns faced by novices and veterans to provide a reference for the investigation and review of CBP studies.

Inferring functional connectivity in fMRI using minimum partial correlation

“…Although this paper only aims at estimating the connections between nodes, we have also faced the problem of parcelling a whole brain into nodes in this study. This is because that there is yet no widely-accepted parcellation for functional connectivity inference [46,47] . Although it has been recommended to use data-driven approaches, such as high-dimensional independent component analysis (ICA), rather than gross structural atlas based parcellation that may not finely correspond to real functional boundaries in the data [48] , we chose the AAL atlas (which shows greater stability than other atlases tested [49] ), because of its simplicity and interpretability.…”

Characteristics of structural and functional organization of the brain

“…Ключевыми для понимания организации высших мозговых функций являются два основных поло-жения -функциональная специализация и функцио-нальная интеграция различных отделов головного мозга [3,5,10,11]. В основе функциональной специализации лежит представление о ведущей роли определенных обла-стей головного мозга, преимущественно коры больших полушарий, в выполнении тех или иных когнитивных функций.…”

“…При этом следует учитывать тот факт, что в коре полушарий головного мозга выделяют от 50 до 200 разных зон, функциональная значимость которых является пред-метом проводимых исследований [12]. Эти зоны отлича-ются друг от друга по своей микроархитектонике (цито-, миело-и рецепторо-архитектонике), связям (как аффе-рентным и эфферентным) и функциям [11]. Функцио-нальная интеграция подразумевает наличие динамиче-ских связей между различными отделами головного моз-га, обеспечивающих осуществление когнитивных и дру-гих функций.…”

Striatal subdivisions that coherently interact with multiple cerebrocortical networks

“…The cerebral cortex has been divided into functional cerebrocortical areas (Bzdok et al, 2015; Eickhoff, Laird, Fox, Bzdok, & Hensel, 2016; Eickhoff, Thirion, Varoquaux, & Bzdok, 2015; Finn et al, 2015; Genon et al, 2017; Jackson, Bajada, Rice, Cloutman, & Lambon Ralph, 2018; Jakobsen et al, 2018; Mars et al, 2011; Shen, Tokoglu, Papademetris, & Constable, 2013; Wang, Fan, et al, 2015; Wang, Yang, et al, 2015; Wang et al, 2017; Zhang & Li, 2012; Zhang et al, 2016). There are two major approaches for areal parcellation (Schaefer et al, 2017): Clustering analyses reveal cortical areas that represent the global cortical functional architecture well.…”