Issues about the fMRI of the human spinal cord

Giove, Federico; Garreffa, Girolamo; Giulietti, Giovanni; Mangia, Silvia; Colonnese, Claudio; Maraviglia, B.

doi:10.1016/j.mri.2004.10.015

Cited by 75 publications

(54 citation statements)

References 57 publications

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“…Indeed, by using a z-shimmed EPI acquisition (34) we have minimized through slice dephasing, reducing signal loss due to periodic susceptibility differences along the cord, and preserved cord shape across slices. Third, concerning the orientation of the major draining veins, which run parallel to the long axis of the cord, these are likely to be parallel to the main static magnetic field, and so should theoretically contribute little to recorded signal (53). By performing comprehensive slice-wise physiological noise removal, based on independent measurement of each subject's physiological signals, we have attempted to remove such confounding noise sources (primarily cardiac in origin) that have previously been observed near the surface of the cord with ICA based analysis (25,35).…”

Section: Discussionmentioning

confidence: 99%

Intrinsically organized resting state networks in the human spinal cord

Kong

Eippert

Beckmann

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

144

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Spontaneous fluctuations in functional magnetic resonance imaging (fMRI) signals of the brain have repeatedly been observed when no task or external stimulation is present. These fluctuations likely reflect baseline neuronal activity of the brain and correspond to functionally relevant resting-state networks (RSN). It is not known however, whether intrinsically organized and spatially circumscribed RSNs also exist in the spinal cord, the brain's principal sensorimotor interface with the body. Here, we use recent advances in spinal fMRI methodology and independent component analysis to answer this question in healthy human volunteers. We identified spatially distinct RSNs in the human spinal cord that were clearly separated into dorsal and ventral components, mirroring the functional neuroanatomy of the spinal cord and likely reflecting sensory and motor processing. Interestingly, dorsal (sensory) RSNs were separated into right and left components, presumably related to ongoing hemibody processing of somatosensory information, whereas ventral (motor) RSNs were bilateral, possibly related to commissural interneuronal networks involved in central pattern generation. Importantly, all of these RSNs showed a restricted spatial extent along the spinal cord and likely conform to the spinal cord's functionally relevant segmental organization. Although the spatial and temporal properties of the dorsal and ventral RSNs were found to be significantly different, these networks showed significant interactions with each other at the segmental level. Together, our data demonstrate that intrinsically highly organized resting-state fluctuations exist in the human spinal cord and are thus a hallmark of the entire central nervous system. fMRI | spinal cord | resting state | connectivity | networks F unctional magnetic resonance imaging (fMRI) has been used to study the functional connectivity of the human brain, with spontaneous fluctuations in the resting-state fMRI signal (1-3) attracting much attention in the past few years (for review, see refs. 4-6). Brain regions showing temporally coherent spontaneous fluctuations constitute several anatomically consistent "resting state networks" (RSNs), such as visual, auditory, sensorymotor, executive control, and default mode networks (7-11). Consequently, analyses of RSNs are rapidly emerging as a powerful tool for in vivo mapping of neural circuitry in the human brain and one such approach for exploring RSNs is independent component analysis (ICA) (12)(13)(14). ICA decomposes the data into spatially independent and temporally coherent source signals/ components. The advantage of ICA over more traditional seedbased approaches (15) is that it is a model-free, data-driven multiple-regression approach, i.e., within the ICA framework we can account for multiple underlying signal contributions (artifactual or neuronal in origin) simultaneously and thereby disentangle these different contributions to the measured observations (16). To date, ICA has been used not only to characterize brain con...

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Section: Discussionmentioning

confidence: 99%

Intrinsically organized resting state networks in the human spinal cord

Kong

Eippert

Beckmann

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

144

View full text Add to dashboard Cite

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“…In the spinal cord, there is poor field homogeneity caused by surrounding tissue interfaces, as well as movement artifacts related to pulsations of the cerebral spinal fluid. For the cervical spinal cord, there are the additional problems of respiratory motion and effects of changing lung volume, adding to poor field homogeneity (18). There are now several reports of pain-evoked activity in both the human (19)(20)(21) and rat (22,23) spinal cord imaged with fMRI, but the technique still poses some challenges, including signal localization, and so more work needs to be performed before this can become a widespread method of investigation for pain researchers.…”

Section: Spinal Cord Imagingmentioning

confidence: 99%

Pain imaging in health and disease — how far have we come?

Schweinhardt

Bushnell²

2010

J. Clin. Invest.

191

145

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Since modern brain imaging of pain began 20 years ago, networks in the brain related to pain processing and those related to different types of pain modulation, including placebo, have been identified. Functional and anatomical connectivity of these circuits has begun to be analyzed. Imaging in patients suggests that chronic pain is associated with altered function and structural abnormalities in pain modulatory circuits. Moreover, biochemical alterations associated with chronic pain are being identified that provide information on cellular correlates as well as potential mechanisms of structural changes. Data from these brain imaging studies reinforce the idea that chronic pain leads to brain changes that could have functional significance.

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“…The MRI images in this report were all obtained just after admissions, and thus the extents of visible MRI abnormalities do not match completely to those observed pathologically in autopsy, from 15 up to 60 days after injury. Periodic MRI study of SCI patients, in both subacute and chronic phases, using some of the newer MRI imaging methods (eg, functional MRI, spectroscopy, diffusion tensor imaging), [9][10][11][12] would be very helpful to monitor the longitudinal progress and the visible extent of SCI on imaging for correlation with clinical findings. For example, it would be informative to learn how long it would take for a moderate or severe contusion to form cystic lesions.…”

Section: Autopsy Findingsmentioning

confidence: 99%

Subacute human spinal cord contusion: few lymphocytes and many macrophages

Chang

2006

Spinal Cord

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Study design: Clinicopathological correlation of three cases of subacute cervical spinal cord contusions. Objective: To correlate the pathology of subacute cervical spinal cord injury (SCI) with imaging and clinical-functional studies, and to compare with findings from previous human SCI studies and animal models of SCI. Setting: Department of Pathology, SUNY-Upstate Medical University, Syracuse, NY, USA. Method: Post mortem pathology report. Case report/Results: The clinical, radiological, and pathological findings of three cases of subacute spinal cord contusions are described in detail. The postinjury survival periods were 15, 20, and 60 days, respectively. Extensive microglia/macrophage infiltrations without significant lymphocytes are seen in all cases. Free radical injury as assessed by immunocytochemistry for 4-hydroxynonenal and nitrotyrosine showed a labeling pattern parallel to that of the macrophage distribution at 15 days, but no significant labeling in the injury sites at 20 and 60 days. Conclusion: The present report, though limited in sample size, shows plenty of activated microglia/macrophages in human SCI up to 60 days postinjury. This observation not only confirms similar findings in previous studies, but also raises an intriguing question of potential interactions between these activated microglia/macrophages and the experimental therapy, proposed by some authors, of injecting exogenously activated macrophages to promote SCI repair. The small number of human SCI cases (in this as well as in most other single medical centers) available for detailed study illustrates the need for the establishment of a consortium of human SCI tissue banks.

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Issues about the fMRI of the human spinal cord

Cited by 75 publications

References 57 publications

Intrinsically organized resting state networks in the human spinal cord

Intrinsically organized resting state networks in the human spinal cord

Pain imaging in health and disease — how far have we come?

Subacute human spinal cord contusion: few lymphocytes and many macrophages

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