title: Functional Connectivity-Based Parcellation of the Thalamus: An Unsupervised Clustering Method and Its Validity Investigation.
abstract: Node definition or delineating how the brain is parcellated into individual functionally related regions is the first step to accurately map the human connectome. As a result, parcellation of the human brain has drawn considerable attention in the field of neuroscience. The thalamus is known as a relay in the human brain, with its nuclei sending fibers to the cortical and subcortical regions. Functional magnetic resonance imaging techniques offer a way to parcellate the thalamus in vivo based on its connectivity properties. However, the parcellations from previous studies show that both the number and the distribution of thalamic subdivisions vary with different cortical segmentation methods. In this study, we used an unsupervised clustering method that does not rely on a priori information of the cortical segmentation to parcellate the thalamus. Instead, this approach is based on the intrinsic resting-state functional connectivity profiles of the thalamus with the whole brain. A series of cluster solutions were obtained, and an optimal solution was determined. Furthermore, the validity of our parcellation was investigated through the following: (1) identifying specific resting-state connectivity patterns of thalamic parcels with different brain networks and (2) investigating the task activation and psychophysiological interactions of specific thalamic clusters during 8-Hz flashing checkerboard stimulation with simultaneous finger tapping. Together, the current study provides a reliable parcellation of the thalamus and enhances our understating of thalamic. Furthermore, the current study provides a framework for parcellation that could be potentially extended to other subcortical and cortical regions.
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .|2 Beijing City Key Lab for Medical Physics and Engineering, School of Physics, Peking University , Beijing, China .
authors.forename: Yang
authors.initials: Y
authors.lastname: Fan
authors.affiliation: 3 McLean Imaging Center, McLean Hospital , Belmont, Massachusetts.|4 Harvard Medical School, Harvard University , Boston, Massachusetts.
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Nickerson
authors.affiliation: 5 Department of Biomedical Engineering, Dalian University of Technology , Dalian, China .
authors.forename: Huanjie
authors.initials: H
authors.lastname: Li
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .|2 Beijing City Key Lab for Medical Physics and Engineering, School of Physics, Peking University , Beijing, China .
authors.forename: Yajun
authors.initials: Y
authors.lastname: Ma
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .|2 Beijing City Key Lab for Medical Physics and Engineering, School of Physics, Peking University , Beijing, China .
authors.forename: Bingjiang
authors.initials: B
authors.lastname: Lyu
authors.affiliation: 6 State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics , Chinese Academy of Sciences, Beijing, China .
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Miao
authors.affiliation: 6 State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics , Chinese Academy of Sciences, Beijing, China .
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuo
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .
authors.forename: Jianqiao
authors.initials: J
authors.lastname: Ge
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .
authors.forename: Qihong
authors.initials: Q
authors.lastname: Zou
authors.affiliation: 1 Center for MRI Research, Peking University , Beijing, China .|2 Beijing City Key Lab for Medical Physics and Engineering, School of Physics, Peking University , Beijing, China .|7 McGovern Institute for Brain Research, Peking University , Beijing, China .
authors.forename: Jia-Hong
authors.initials: JH
authors.lastname: Gao
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D016000:Cluster Analysis; D063132:Connectome / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D015203:Reproducibility of Results; D013788:Thalamus / Q000502:physiology*; D055815:Young Adult
keywords: K-means; functional connectivity; parcellation; resting-state fMRI; thalamus; visuomotor task