title: Investigating resting-state functional connectivity in the cervical spinal cord at 3T.
abstract: The study of spontaneous fluctuations in the blood-oxygen-level-dependent (BOLD) signal has recently been extended from the brain to the spinal cord. Two ultra-high field functional magnetic resonance imaging (fMRI) studies in humans have provided evidence for reproducible resting-state connectivity between the dorsal horns as well as between the ventral horns, and a study in non-human primates has shown that these resting-state signals are impacted by spinal cord injury. As these studies were carried out at ultra-high field strengths using region-of-interest (ROI) based analyses, we investigated whether such resting-state signals could also be observed at the clinically more prevalent field strength of 3T. In a reanalysis of a sample of 20 healthy human participants who underwent a resting-state fMRI acquisition of the cervical spinal cord, we were able to observe significant dorsal horn connectivity as well as ventral horn connectivity, but no consistent effects for connectivity between dorsal and ventral horns, thus replicating the human 7T results. These effects were not only observable when averaging along the acquired length of the spinal cord, but also when we examined each of the acquired spinal segments separately, which showed similar patterns of connectivity. Finally, we investigated the robustness of these resting-state signals against variations in the analysis pipeline by varying the type of ROI creation, temporal filtering, nuisance regression and connectivity metric. We observed that - apart from the effects of band-pass filtering - ventral horn connectivity showed excellent robustness, whereas dorsal horn connectivity showed moderate robustness. Together, our results provide evidence that spinal cord resting-state connectivity is a robust and spatially consistent phenomenon that could be a valuable tool for investigating the effects of pathology, disease progression, and treatment response in neurological conditions with a spinal component, such as spinal cord injury.
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. Electronic address: falk.eippert@ndcn.ox.ac.uk.
authors.forename: Falk
authors.initials: F
authors.lastname: Eippert
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Magnetic Resonance Imaging Research Centre, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yazhuo
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
authors.forename: Anderson M
authors.initials: AM
authors.lastname: Winkler
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
authors.forename: Jesper L
authors.initials: JL
authors.lastname: Andersson
authors.affiliation: Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Finsterbusch
authors.affiliation: Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Büchel
authors.affiliation: Clinical Research and Imaging Centre, University of Bristol, Bristol, UK.
authors.forename: Jonathan C W
authors.initials: JCW
authors.lastname: Brooks
authors.affiliation: Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
authors.forename: Irene
authors.initials: I
authors.lastname: Tracey
mesh_terms: D000328:Adult; D066193:Cervical Cord / Q000000981:diagnostic imaging / Q000502:physiology*; D063132:Connectome / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D066148:Spinal Cord Dorsal Horn / Q000000981:diagnostic imaging / Q000502:physiology*; D066151:Spinal Cord Ventral Horn / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult