Human brain mapping: A systematic comparison of parcellation methods for the human cerebral cortex

Salim Arslan, Sofia Ira Ktena, Antonios Makropoulos, Emma C. Robinson, Daniel Rueckert, Sarah Parisot
2018 NeuroImage  
The macro-connectome elucidates the pathways through which brain regions are structurally connected or functionally coupled to perform a specific cognitive task. It embodies the notion of representing and understanding all connections within the brain as a network, while the subdivision of the brain into interacting functional units is inherent in its architecture. As a result, the definition of network nodes is one of the most critical steps in connectivity network analysis. Although brain
more » ... ses obtained from cytoarchitecture or anatomy have long been used for this task, connectivity-driven methods have arisen only recently, aiming to delineate more homogeneous and functionally coherent regions. This study provides a systematic comparison between anatomical, connectivitydriven and random parcellation methods proposed in the thriving field of brain parcellation. Using functional MRI data from the Human Connectome Project and a plethora of quantitative evaluation techniques investigated in the literature, we evaluate 10 subject-level and 24 groupwise parcellation methods at different resolutions. We assess the accuracy of parcellations from four different aspects: (1) reproducibility across different acquisitions and groups, (2) fidelity to the underlying connectivity data, (3) agreement with fMRI task activation, myelin maps, and cytoarchitectural areas, and (4) network analysis. This extensive evaluation of different parcellations generated at the subject and group the underlying data, such methods can potentially provide highly homogeneous and functionally coherent parcels and separate regions with different patterns of connectivity more accurately. With this idea in mind, several connectivitydriven parcellation methods have been proposed, usually in association with clustering techniques (Thirion et al., 2014) . These methods are based on hier-50 archical clustering (Mumford et al., 2010; Bellec et al., 2010; Moreno-Dominguez et al., 2014) , k -means (and its fuzzy counterpart) (Tomassini et al., 2007; Mezer et al., 2009; Golland et al., 2008) , Gaus-155 is carried out separately for each of the 86 different functional contrasts, over 7 different tasks, including the motor protocol, the relational protocol, the social protocol, the language protocol, the emotion protocol, the gambling protocol, and the working memory protocol ( Barch et al., 2013) . The analysis is performed across sessions (single subject activation maps) and then across subjects 160 (groupwise activation map). We compute the group average myelin maps by averaging all subjects' myelin maps, while the average Brodmann map is obtained implementations are available (Honnorat et al., 2015; Parisot et al., 2016b) .
doi:10.1016/j.neuroimage.2017.04.014 pmid:28412442 fatcat:yrf2qf42snfkjlec6twcsba3ja