Reproducibility of resting state spinal cord networks in healthy volunteers at 7 Tesla

Barry, Robert; Rogers, Baxter P.; Conrad, Benjamin; Smith, Seth A.; Gore, John C.

doi:10.1016/j.neuroimage.2016.02.058

Cited by 63 publications

(155 citation statements)

References 23 publications

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“…These networks also receive excitatory and inhibitory inputs from higher centers, which further modulate SC processing (Heinricher et al, 2009; Yang and Gorassini, 2006). Recently, intrinsic resting state networks between the left and right dorsal horns and the left and right ventral horns were identified with fMRI in humans (Barry et al, 2016; Barry et al, 2014) and non-human primates (Kong et al, 2014), and injury to the SC has been demonstrated to disrupt these networks (Chen et al, 2015). Based on these findings, the coordinated activity between the hemicords may represent the state of normal sensory processing, explaining the absence of the lateralization of the activity detected in this study.…”

Section: Discussionmentioning

confidence: 99%

Functional magnetic resonance imaging of the cervical spinal cord during thermal stimulation across consecutive runs

et al. 2016

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The spinal cord is the first site of nociceptive processing in the central nervous system and has a role in the development and perpetuation of clinical pain states. Advancements in functional magnetic resonance imaging are providing a means to non-invasively measure spinal cord function, and functional magnetic resonance imaging may provide an objective method to study spinal cord nociceptive processing in humans. In this study, we tested the validity and reliability of functional magnetic resonance imaging using a selective field-of-view gradient-echo echo-planar-imaging sequence to detect activity induced blood oxygenation level-dependent signal changes in the cervical spinal cord of healthy volunteers during warm and painful thermal stimulation across consecutive runs. At the group and subject level, the activity was localized more to the dorsal hemicord, the spatial extent and magnitude of the activity was greater for the painful stimulus than the warm stimulus, and the spatial extent and magnitude of the activity exceeded that of a control analysis. Furthermore, the spatial extent of the activity for the painful stimuli increased across the runs likely reflecting sensitization. Overall, the spatial localization of the activity varied considerably across the runs, but despite this variability, a machine-learning algorithm was able to successfully decode the stimuli in the spinal cord based on the distributed pattern of the activity. In conclusion, we were able to successfully detect and characterize cervical spinal cord activity during thermal stimulation at the group and subject level.

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Section: Discussionmentioning

confidence: 99%

Functional magnetic resonance imaging of the cervical spinal cord during thermal stimulation across consecutive runs

et al. 2016

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“…Recent papers have investigated and found useful connectivity above 0.1 Hz [27,28]. In fact, we have recently shown increased correlations within the center of gray matter horns in the spinal cord when using frequencies from 0.01 to 0.13 Hz [29]. Little is known about the hemodynamic nature of BOLD white matter signal, so exploring band-pass filters beyond the conventional 0.01–0.08 Hz [30] could provide better sensitivity and insights into deciphering the origins of resting state fluctuations and functional connectivity within white matter.…”

Section: Discussionmentioning

confidence: 99%

Effects of anesthesia on resting state BOLD signals in white matter of non-human primates

Wang

Anderson

et al. 2016

Magnetic Resonance Imaging

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Resting state functional magnetic resonance imaging (rsfMRI) has been widely used to measure functional connectivity between cortical regions of the brain. However, there have been minimal reports of bold oxygenation level dependent (BOLD) signals in white matter, and even fewer attempts to detect resting state connectivity. Recently, there has been growing evidence that suggests reliable detection of white matter BOLD signals may be possible. We have previously shown that nearest neighbor inter-voxel correlations of resting state BOLD signal fluctuations in white matter are anisotropic and can be represented by a functional correlation tensor, but the biophysical origins of these signal variations are not clear. We aimed to assess whether MRI signal fluctuations in white matter vary for different baseline levels of neural activity. We performed imaging studies on live squirrel monkeys under different levels of isoflurane anesthesia at 9.4T. We found 1) the fractional power (0.01 – 0.08 Hz) in white matter was between 60 to 75% of the level in gray matter; 2) the power in both gray and white matter low frequencies decreased monotonically in similar manner with increasing levels of anesthesia; 3) the distribution of fractional anisotropy values of the functional tensors in white matter were significantly higher than those in gray matter; and 4) the functional tensor eigenvalues decreased with increasing level of anesthesia. Our results suggest that as anesthesia level changes baseline neural activity, white matter signal fluctuations behave similarly to those in gray matter, and functional tensors in white matter are affected in parallel.

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“…These advanced coils showed improved image quality for fMRI experiments. [29][30][31] Shimming As mentioned in the introduction, one challenge of spinal cord fMRI is the presence of susceptibility artifacts, which appear as image distortions and signal dropout in T 2 *-weighted echo planar images (EPI), typically used for fMRI experiments because of their ultrafast imaging properties. These artifacts are caused by inhomogeneities of the main magnetic field (B 0 ) owing to the presence of structures with different susceptibilities: the bony vertebral structure, the intervertebral disks, and the air-filled lung.…”

Section: Rf Coilsmentioning

confidence: 99%

Functional Magnetic Resonance Imaging of the Spinal Cord: Current Status and Future Developments

Cohen‐Adad

2017

Seminars in Ultrasound, CT and MRI

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Reproducibility of resting state spinal cord networks in healthy volunteers at 7 Tesla

Cited by 63 publications

References 23 publications

Functional magnetic resonance imaging of the cervical spinal cord during thermal stimulation across consecutive runs

Functional magnetic resonance imaging of the cervical spinal cord during thermal stimulation across consecutive runs

Effects of anesthesia on resting state BOLD signals in white matter of non-human primates

Functional Magnetic Resonance Imaging of the Spinal Cord: Current Status and Future Developments

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