Tactile‐associated fMRI recruitment of the cervical cord in healthy subjects

Abstract

Using spinal cord functional magnetic resonance imaging (fMRI), 12 right-handed healthy subjects were scanned during a tactile stimulation of the palm of the right hand. The task-related mean signal change was computed for all activated voxels within the cervical cord, and separately, in the four cord quadrants (right and left anterior, right and left posterior) from C5 to C8. The frequency of fMRI activity at each cord level was obtained by assigning a score of 25% at each active quadrant and by averaging the percentage of active quadrants at each level of all subjects. The difference in the occurrence of fMRI activity (a) in right versus left, and anterior versus posterior cord, and (b) among the different cord levels, was evaluated using a random effect logistic regression model, with the frequency of fMRI activity as the dependent variable and the subject as the grouping factor. The taskrelated mean signal change of all activated voxels of the cord was 3.2% (SD 5 0.8%). During the tactile stimulation, subjects showed a higher occurrence of fMRI cord activity in the right than in the left cervical cord (odds ratio 5 2.25, 95% confidence interval 5 1.31-3.87, P 5 0.003). A significant heterogeneity in frequency of fMRI activity between cord levels was also observed (P < 0.001), with the highest frequencies of fMRI activity detected at C6 and C7. Spinal cord fMRI enables to obtain reliable physiological information on the activity of human spinal circuits associated to tactile stimulation. This holds significant promise for a better planning and conduct of studies of people with diseased spinal cords.

Cervical cord functional MRI changes in relapse-onset MS patients

“…Consistent with the expected regions of neuronal involvement for a tactile stimulation of the palm of the right hand16 17 and with previous cord fMRI studies,8–10 15 18 19 both control subjects and MS patients showed a functional lateralisation of cord activity, which was predominant in the cord side ipsilateral to the stimulus, and a more frequent activation of the posterior than of the anterior cord quadrants. Moreover, all subjects showed cervical cord fMRI activity not only dorsally and at the level corresponding to the dermatome where the stimuli were applied, but also ventrally and in upper cervical cord segments.…”

“…Using a block design (ABAB), where four periods of rest were alternated with four periods of activity (each period of rest and activity consisting of five scans), the subjects were scanned while administering a tactile stimulation of the palm of the right hand, as described elsewhere 8 10 15. To prevent movements of the shoulder, arm, elbow or forearm, subjects' arms were restrained with straps.…”

Mapping of neural activity produced by thermal pain in the healthy human spinal cord and brain stem: a functional magnetic resonance imaging study

“…These challenges include the small physical dimensions of the spinal cord, poor magnetic field homogeneity in the cord due to magnetic susceptibility differences and motion of the spinal cord and cerebral spinal fluid motion. However, such challenges have now been overcome or reduced, with the development of novel techniques by our laboratory and others [9][10][11][12][13][14][15].…”

Tactile Sensory and Pain Networks in the Human Spinal Cord and Brain Stem Mapped by Means of Functional MR Imaging

“…By accommodating the small-diameter structures, proton attenuation weighted spin-echo imaging methods can provide high quality images of the brain stem and spinal cord. 13,16,17 For information on the effectiveness of using fast spin-echo imaging methods in the spinal cord and brain stem see Stroman et al 18 The purpose of this study was to use an established spinal fMRI method [17][18][19] to map areas of neuronal activity in the brain stem and cervical spinal cord that are involved with touch and brush sensations in healthy volunteers. We hypothesize that the full distribution of sensory activity from touch and brush stimuli can be reliably mapped in intact human volunteers by means of spinal fMRI.…”