Functional networks in non-human primate spinal cord and the effects of injury

• Published in: NeuroImage (Orlando, Fla.) Vol. 240; p. 118391
• Main Authors: Sengupta, Anirban, Mishra, Arabinda, Wang, Feng, Li, Muwei, Yang, Pai-Feng, Chen, Li Min, Gore, John C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.10.2021; Elsevier Limited; Elsevier
• Subjects: Behavior; BOLD fMRI; Dorsal column injury; Functional magnetic resonance imaging; Graph Theory; Hypotheses; Independent Component Analysis; Injuries; Magnetic resonance imaging; Physiology; Resting state functional connectivity; Spinal cord; Spinal cord injuries; Time series; Dorsal column injury; Spinal cord; Resting state functional connectivity; Independent Component Analysis; Graph Theory; BOLD fMRI
• ISSN: 1053-8119; 1095-9572; 1095-9572
• DOI: 10.1016/j.neuroimage.2021.118391

•ICA of resting state images revealed new network hubs in cervical spinal cord.•Functional connections between network hubs were stronger on the dominant hand side.•Graph theory identified communities of connectivities within and between segments.•Dorsal column injury affected inter-segment more than intra-segment connectivities. Spontaneous fluctuations of Blood Oxygenation-Level Dependent (BOLD) MRI signal in a resting state have previously been detected and analyzed to describe intrinsic functional networks in the spinal cord of rodents, non-human primates and human subjects. In this study we combined high resolution imaging at high field with data-driven Independent Component Analysis (ICA) to i) delineate fine-scale functional networks within and between segments of the cervical spinal cord of monkeys, and also to ii) characterize the longitudinal effects of a unilateral dorsal column injury on these networks. Seven distinct functional hubs were revealed within each spinal segment, with new hubs detected at bilateral intermediate and gray commissure regions in addition to the bilateral dorsal and ventral horns previously reported. Pair-wise correlations revealed significantly stronger connections between hubs on the dominant hand side. Unilateral dorsal-column injuries disrupted predominantly inter-segmental rather than intra-segmental functional connectivities as revealed by correlation strengths and graph-theory based community structures. The effects of injury on inter-segmental connectivity were evident along the length of the cord both below and above the lesion region. Connectivity strengths recovered over time and there was revival of inter-segmental communities as animals recovered function. BOLD signals of frequency 0.01–0.033 Hz were found to be most affected by injury. The results in this study provide new insights into the intrinsic functional architecture of spinal cord and underscore the potential of functional connectivity measures to characterize changes in networks after an injury and during recovery. [Display omitted]