Jennifer Kornelsen

Noninvasive assessment of the injured human spinal cord by means of functional magnetic resonance imaging

Study design: A magnetic resonance imaging technique that enables indirect detection of neuronal activity has been developed for the spinal cord. In the present study, this method, spinal functional magnetic resonance imaging (fMRI), is applied to the first study of the injured spinal cord, with the goal of better clinical assessment of the entire cord.Objectives: The objectives of this project are: (1) to investigate the neuronal activity that can be detected in the spinal cord caudal to a chronic injury by means of spinal fMRI, and (2) to develop spinal fMRI as a clinical diagnostic tool.Setting: Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada.Methods: fMRI of the spinal cord was carried out in 27 volunteers with cervical or thoracic spinal cord injuries (SCIs). Of these volunteers, 18 had complete injuries, and nine had incomplete injuries. Spinal fMRI was carried out in a 1.5u2009T clinical MR system, using established methods. Thermal stimulation at 10°C was applied to the fourth lumbar dermatome on each leg, and images were obtained of the entire lumbar spinal cord.Results: Areas of neuronal activity were consistently observed in the lumbar spinal cord in response to the thermal stimulation, even when the subjects had no awareness of the sensation. The pattern of activity was notably different compared with noninjured subjects. In general, subjects with complete SCI showed absent or diminished dorsal gray matter activity, but had enhanced ventral activity, particularly contralateral to the stimulation.Conclusions: Spinal fMRI is able to provide a noninvasive assessment of the injured spinal cord that does not depend on the patients perception of the stimulus being applied. This work was carried out on a standard clinical MRI system without modification, and so is readily applicable in most MR units.Sponsorship: This work was funded by a grant from the Canadian Institutes of Health Research (CIHR).

An improved method for spinal functional MRI with large volume coverage of the spinal cord.

To develop a spinal functional MRI (fMRI) method with three‐dimensional coverage of a large extent of the spinal cord with minimal partial volume effects

Human cervical spinal cord funiculi: investigation with magnetic resonance diffusion tensor imaging.

To use spinal cord diffusion tensor imaging (DTI) for investigating human cervical funiculi, acquire axial diffusion magnetic resonance imaging (MRI) data with an in‐plane resolution sufficient to delineate subquadrants within the spinal cord, obtain corresponding DTI metrics, and assess potential regional differences.

Default Mode Network Functional Connectivity Altered in Failed Back Surgery Syndrome

UNLABELLEDnThe purpose of this study was to identify alterations in the default mode network of failed back surgery syndrome patients as compared to healthy subjects. Resting state functional magnetic resonance imaging was conducted at 3 Tesla and data were analyzed with an independent component analysis. Results indicate an overall reduced functional connectivity of the default mode network and recruitment of additional pain modulation brain regions, including dorsolateral prefrontal cortex, insula, and additional sensory motor integration brain regions, including precentral and postcentral gyri, for failed back surgery syndrome patients.nnnPERSPECTIVEnThis article presents alterations in the default mode network of chronic low back pain patients with failed back surgery syndrome as compared to healthy participants.

Advanced MR imaging techniques and characterization of residual anatomy

Advances in technology in recent decades have contributed to rapid developments in non-invasive methods for imaging human anatomy, and advanced imaging methods are now one of the primary tools for clinical diagnosis after neurological trauma or disease. Here we review the current and upcoming capabilities of one of the most rapidly developing methods, magnetic resonance imaging (MRI). The underlying theory is introduced so that the reasons for the strengths, weaknesses, and future expectations of this method, can be explained. Current techniques for imaging anatomical changes, inflammation, and changes in white matter, axonal integrity, blood flow and function, are reviewed. Applications for specific purposes of assessing traumatic injury in the brain or spinal cord, and for multiple-sclerosis are also presented, and are used as examples of how the advanced techniques are being used in practice.

Emotion-dependent responses in spinal cord neurons: a spinal fMRI study.

Previous research has demonstrated that emotional stimuli receive preferential processing in the brain. In the current study, functional magnetic resonance imaging was utilized to determine if emotion-specific responses are detectable in the cervical spinal cord. During the passive (i.e., non-motoric) perception of images, activity was detected in the left dorsal and right ventral spinal cord in response to negative emotional stimuli; however, this pattern was reversed in response to neutral and positive stimuli. Critically, during active motoric responses to images, there was greater activity in the ventral cervical spinal cord in response to negative emotional stimuli than to neutral stimuli. These results demonstrate preferential motor responses to negative emotional images by the spinal cord, likely indicating an enhancement of activity in response to threat.

Altered Neural Activity Associated with Mindfulness during Nociception: A Systematic Review of Functional MRI.

Objective: To assess the neural activity associated with mindfulness-based alterations of pain perception. Methods: The Cochrane Central, EMBASE, Ovid Medline, PsycINFO, Scopus, and Web of Science databases were searched on 2 February 2016. Titles, abstracts, and full-text articles were independently screened by two reviewers. Data were independently extracted from records that included topics of functional neuroimaging, pain, and mindfulness interventions. Results: The literature search produced 946 total records, of which five met the inclusion criteria. Records reported pain in terms of anticipation (n = 2), unpleasantness (n = 5), and intensity (n = 5), and how mindfulness conditions altered the neural activity during noxious stimulation accordingly. Conclusions: Although the studies were inconsistent in relating pain components to neural activity, in general, mindfulness was able to reduce pain anticipation and unpleasantness ratings, as well as alter the corresponding neural activity. The major neural underpinnings of mindfulness-based pain reduction consisted of altered activity in the anterior cingulate cortex, insula, and dorsolateral prefrontal cortex.

Continuous Descending Modulation of the Spinal Cord Revealed by Functional MRI

Spontaneous variations in spinal cord activity may arise from regulation of any of a number of functions including sensory, motor, and autonomic control. Here, we use functional MRI (fMRI) of healthy participants to identify properties of blood oxygenation-level dependent (BOLD) variations in the spinal cord in response to knowledge that either a noxious stimulus is impending, or that no stimulus is to be expected. Expectation of a noxious stimulus, or no stimulus, is shown to have a significant effect on wide-spread BOLD signal variations in the spinal cord over the entire time period of the fMRI acquisition. Coordination of BOLD responses between/within spinal cord and brainstem regions are also influenced by this knowledge. We provide evidence that such signal variations are the result of continuous descending modulation of spinal cord function. BOLD signal variations in response to noxious stimulation of the hand are also shown, as in previous studies. The observation of both continuous and reactive BOLD responses to emotional/cognitive factors and noxious peripheral stimulation may have important implications, not only for our understanding of endogenous pain modulation, but also in showing that spinal cord activity is under continuous regulatory control.

A neural correlate of visceral emotional responses: evidence from fMRI of the thoracic spinal cord

Functional magnetic resonance imaging (fMRI) of thoracic spinal cord neurons was used to examine the neural correlates of visceral emotional responses. Participants completed four spinal fMRI runs involving passive viewing (i.e. no movement) and motoric responses to negative or neutral images. Negative images, particularly in the movement condition, elicited robust activity in motoric nuclei, indicating action preparedness. These images also enhanced activity in autonomic and sensory nuclei, thus providing a clear neural representation of visceral responses to emotional stimuli.

Assessing Nociception by fMRI of the Human Spinal Cord: A Systematic Review

OBJECTIVE To assess the use of fMRI of the spinal cord in measuring noxious stimulation. METHODS The Scopus, Medline, EMBASE, and Web of Science databases were searched, along with the reference lists of included articles. Two independent reviewers screened abstracts, full-text articles, and extracted data. Original research was included if fMRI of the human spinal cord was used to measure responses to noxious stimulation. RESULTS Of the 192 abstracts screened, 19 met the search criteria and were divided according to their focus: investigating pain responses (n = 6), methodology (n = 6), spinal cord injury (n = 2), or cognition–pain interactions (n = 5). All but one study appear to have observed activity in ipsilateral and dorsal gray matter regions in response to noxious stimuli, although contralateral or ventral activity was also widely observed. CONCLUSIONS Although nociception can be investigated using spinal fMRI, establishing reliability, standardizing methodology, and reporting of results will greatly advance this field.