Functional Preservation and Reorganization of Brain during Motor Imagery in Patients with Incomplete Spinal Cord Injury: A Pilot fMRI Study.

Xin Chen,Zhigang Qi,Kuncheng Li,Wen Qin,Weimin Zheng,Nan Chen,Lu Wan

doi:10.3389/fnhum.2016.00046

Abstract

Motor imagery (MI) is a cognitive process involved in mentally rehearsing movement representations, and it has great potential for the rehabilitation of motor function in patients with spinal cord injuries. The aim of this study was to explore changes in the brain activation patterns in incomplete spinal cord injury (ISCI) patients during motor execution (ME) and MI tasks, and to thereby explore whether MI shares similar motor-related networks with ME in ISCI patients. Seventeen right-handed ISCI patients with impaired motor function of their right ankles and 17 age- and gender-matched healthy controls were enrolled in this study. The activation patterns of the ISCI subjects and those of the healthy subjects were compared, both during mental dorsi-plantar flexion of the right ankle (the MI task) and the actual movement of the joint (the ME task). The patients and the healthy controls shared similar activation patterns during the MI or ME tasks. The activation patterns of the MI task between the patients and the healthy controls were more similar than those of the ME task. These findings indicate that the MI network is more functionally preserved than the ME network in ISCI patients. In addition, increased activation in the motor-related regions during ME task, and decreased activation in the parietal regions during both ME and MI tasks, were identified in the ISCI patients compared to the healthy controls, indicating a functional reorganization of these regions after ISCI. The functional preservation and reorganization of the MI network in the ISCI patients suggests a potential role for MI training in motor rehabilitation.

Highlights

Motor imagery (MI) is defined as a dynamic state in which a subject mentally performs a specific motor action without producing a motor output (Guillot et al, 2012; Di Rienzo et al, 2014b)
When a conjunction analysis was performed between the MI and motor execution (ME) tasks, overlapping activation regions are shown in Figure 2A and Table S1
In the incomplete SCI (ISCI) group, the coactivation pattern was observed in the following regions: the bilateral supplementary motor area (SMA), the inferior frontal operculum and cerebellum lobule 6, left cerebellum Crus 1, the anterior insula, and the right middle frontal gyrus (MFG; Figure 4A and Table S2)

Summary

Introduction

Motor imagery (MI) is defined as a dynamic state in which a subject mentally performs a specific motor action without producing a motor output (Guillot et al, 2012; Di Rienzo et al, 2014b). MI has been used for improving the motor rehabilitation in stroke (Dickstein et al, 2014), Parkinson’s syndrome (Wondrusch and Schuster-Amft, 2013), and complete spinal cord injury (CSCI) patients (Grangeon et al, 2012; Di Rienzo et al, 2014a). Previous functional MRI studies (Alkadhi et al, 2005; Cramer et al, 2005, 2007; HotzBoendermaker et al, 2008; Gustin et al, 2010) have found that the brain activation patterns of the MI task in CSCI patients were largely similar to those of the attempted movements. Since the CSCI patients have completely lost their motor ability in the affected limbs, comparing the activation patterns between the MI and ME in the incomplete SCI (ISCI) patients (whose afferent and efferent pathways are partially preserved) may provide additional information about the relationship between MI and ME

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Conclusion