title: Altered Effective Connectivity of the Primary Motor Cortex in Stroke: A Resting-State fMRI Study with Granger Causality Analysis.
abstract: The primary motor cortex (M1) is often abnormally recruited in stroke patients with motor disabilities. However, little is known about the alterations in the causal connectivity of M1 following stroke. The purpose of the present study was to investigate whether the effective connectivity of the ipsilesional M1 is disturbed in stroke patients who show different outcomes in hand motor function. 23 patients with left-hemisphere subcortical stroke were selected and divided into two subgroups: partially paralyzed hands (PPH) and completely paralyzed hands (CPH). Further, 24 matched healthy controls (HCs) were recruited. A voxel-wise Granger causality analysis (GCA) on the resting-state fMRI data between the ipsilesional M1 and the whole brain was performed to explore differences between the three groups. Our results showed that the influence from the frontoparietal cortices to ipsilesional M1 was diminished in both stroke subgroups and the influence from ipsilesional M1 to the sensorimotor cortices decreased greater in the CPH group than in the PPH group. Moreover, compared with the PPH group, the decreased influence from ipsilesional M1 to the contralesional cerebellum and from the contralesional superior parietal lobe to ipsilesional M1 were observed in the CPH group, and their GCA values were positively correlated with the FMA scores; Conversely, the increased influence from ipsilesional M1 to the ipsilesional middle frontal gyrus and middle temporal gyrus were observed, whose GCA values were negatively correlated with the FMA scores. This study suggests that the abnormalities of casual flow in the ipsilesional M1 are related to the severity of stroke-hand dysfunction, providing valuable information to understand the deficits in resting-state effective connectivity of motor execution and the frontoparietal motor control network during brain plasticity following stroke.
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Mingxia
authors.initials: M
authors.lastname: Fan
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.
authors.forename: Dazhi
authors.initials: D
authors.lastname: Yin
authors.affiliation: Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, 200040, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, 200040, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Jia
authors.affiliation: Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, 200040, China.
authors.forename: Chaozheng
authors.initials: C
authors.lastname: Tang
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, 200062, China.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Gong
mesh_terms: D000368:Aged; D005260:Female; D006225:Hand / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010243:Paralysis / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology; D020127:Recovery of Function; D020521:Stroke / Q000503:physiopathology*