Alterations in Cortical Sensorimotor Connectivity following Complete Cervical Spinal Cord Injury: A Prospective Resting-State fMRI Study

Abstract

Functional magnetic resonance imaging (fMRI) studies have demonstrated alterations during task-induced brain activation in spinal cord injury (SCI) patients. The interruption to structural integrity of the spinal cord and the resultant disrupted flow of bidirectional communication between the brain and the spinal cord might contribute to the observed dynamic reorganization (neural plasticity). However, the effect of SCI on brain resting-state connectivity patterns remains unclear. We undertook a prospective resting-state fMRI (rs-fMRI) study to explore changes to cortical activation patterns following SCI. With institutional review board approval, rs-fMRI data was obtained in eleven patients with complete cervical SCI (>2 years post injury) and nine age-matched controls. The data was processed using the Analysis of Functional Neuroimages software. Region of interest (ROI) based analysis was performed to study changes in the sensorimotor network using pre- and post-central gyri as seed regions. Two-sampled t-test was carried out to check for significant differences between the two groups. SCI patients showed decreased functional connectivity in motor and sensory cortical regions when compared to controls. The decrease was noted in ipsilateral, contralateral, and interhemispheric regions for left and right precentral ROIs. Additionally, the left postcentral ROI demonstrated increased connectivity with the thalamus bilaterally in SCI patients. Our results suggest that cortical activation patterns in the sensorimotor network undergo dynamic reorganization following SCI. The presence of these changes in chronic spinal cord injury patients is suggestive of the inherent neural plasticity within the central nervous system.

Delayed pain decrease following M1 tDCS in spinal cord injury: A randomized controlled clinical trial

“…tDCS mechanisms are related to its influence on sodium and calcium channels opening and NMDA receptors excitability [50], while longlasting effects are analogous to activity-dependent synaptic plasticity, namely long-term potentiation (LTP) and long-term depression (LTD) [51][52][53]. Structural, functional and connectivity alterations at the cortical level have been described in patients with SCI, especially in the somatosensory cortex, consequently to the injury itself, as well as a result of the lack of sensory and motor inputs [54][55][56]; these changes being related to neuropathic pain [57]. Therefore, it is possible that patients with SCI sustain a decline in plasticity mechanisms as compared to those observed in healthy subjects, and therefore, tDCS related neuroplastic mechanisms may occur in a delayed manner.…”

Cortical Reorganization of Sensorimotor Systems and the Role of Intracortical Circuits After Spinal Cord Injury

“…Activation of novel secondary motor areas immediately after injury could reflect their involvement in the development of new motor strategies. The resting-state functional connectivity between brain regions also seems to change after spinal cord injury in humans [85][86][87].…”

Functional and Symptomatic Improvement After Cellular Therapy in a Pediatric Case of Chronic Traumatic Incomplete Spinal Cord Injury

“…The strengthening of the abdominals and back extensors improved balance and lower limb control. A fMRI study of the brain demonstrated changes to cortical activation patterns following SCI [31] . The study provided evidence that the sensory-motor network undergoes dynamic reorganization following SCI, which was also observed in our patient.…”