Brain Activation Evoked by Motor Imagery in Pediatric Patients with Complete Spinal Cord Injury

Abstract

Background and purpose: Currently, there is no effective treatment for pediatric patients with complete spinal cord injury. Motor imagery has been proposed as an alternative to physical training for patients who are unable to move voluntarily. Our aim was to reveal the potential mechanism of motor imagery in the rehabilitation of pediatric complete spinal cord injury.

Materials and methods: Twenty-six pediatric patients with complete spinal cord injury and 26 age- and sex-matched healthy children as healthy controls were recruited. All participants underwent the motor imagery task-related fMRI scans, and additional motor execution scans were performed only on healthy controls. First, we compared the brain-activation patterns between motor imagery and motor execution in healthy controls. Then, we compared the brain activation of motor imagery between the 2 groups and compared the brain activation of motor imagery in pediatric patients with complete spinal cord injury and that of motor execution in healthy controls.

Results: In healthy controls, compared with motor execution, motor imagery showed increased activation in the left inferior parietal lobule and decreased activation in the left supplementary motor area, paracentral lobule, middle cingulate cortex, and right insula. In addition, our results revealed that the 2 groups both activated the bilateral supplementary motor area, middle cingulate cortex and left inferior parietal lobule, and supramarginal gyrus during motor imagery. Compared with healthy controls, higher activation in the bilateral paracentral lobule, supplementary motor area, putamen, and cerebellar lobules III-V was detected in pediatric complete spinal cord injury during motor imagery, and the activation of these regions was even higher than that of healthy controls during motor execution.

Conclusions: Our study demonstrated that part of the motor imagery network was functionally preserved in pediatric complete spinal cord injury and could be activated through motor imagery. In addition, higher-level activation in sensorimotor-related regions was also found in pediatric complete spinal cord injury during motor imagery. Our findings may provide a theoretic basis for the application of motor imagery training in pediatric complete spinal cord injury.

FIG 1.

Brain activation of HCs during ME and MI and the activation of pediatric patients with CSCI during MI. Typical brain regions with activation in HCs during ME are shown in A, mainly including the left PCL, PSMC, middle cingulate cortex, precuneus, and bilateral insula, SMA (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥172). Typical brain regions with activation in HCs during MI in B, mainly including the left IPL and the bilateral SMA, middle cingulate cortex (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥248). Typical brain regions with activation in pediatric patients with CSCI during MI are shown in C, mainly including the bilateral SMA, PCL, PSMC, putamen, pallidum, insula, superior temporal gyrus, middle cingulate cortex, cerebellar lobules III–V, and the left IPL, precuneus, and supramarginal gyrus (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥199). PSMC indicates primary sensory and motor cortex.

FIG 2.

Brain regions with significant differences between MI and ME in HCs. Compared with ME, MI of HCs shows increased activation in the left IPL (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥113, red) as well as decreased activation in the left SMA, PCL, middle cingulate cortex, and right insula (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥24; blue). R indicates right; L, left.

FIG 3.

Brain regions with increased activation in pediatric patients with CSCI during MI. Compared with HCs, pediatric patients with CSCI show increased activation in bilateral PCL, SMA, putamen, and cerebellar lobules III–V (uncorrected voxelwise P < .001, FWE-corrected cluster-level P < .05 and cluster ≥91). R indicates right; L, left; Ceb3–5, cerebellar lobules III–V.