Sequential neural activity in sensorimotor area and mirror neural system for graded mirror therapy with imagined hand movements

Article type: Research Article

Authors: Gu, Pengpeng^{a; b; 1} | Tu, Wenzhan^{b; 1} | Deng, Fen^c | Ye, Limei^d | Li, Sisi^{a; b} | Bai, Guanghui^e | Jin, Xiaofeng^f | Li, Shasha^{g; h; *} | Jiang, Songhe^{a; b; *}

Affiliations: [a] Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China | [b] Intelligent Rehabilitation International Alliance, Wenzhou Medical University, Wenzhou, China | [c] Department of Ultrasonography, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China | [d] Department of Medical Imaging, Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China | [e] Department of Radiology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China | [f] School of Mental Health, Wenzhou Medical University, Wenzhou, China | [g] Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA | [h] Harvard Medical School, Boston, MA, USA

Correspondence: [*] Address for correspondence: Songhe Jiang, MD, PhD, Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou, Wenzhou, China. Tel.: +86 0577 85676695; Fax: +86 0577 88832693; E-mail: jiangsonghe@wmu.edu.cn and Shasha Li, MD, PhD, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, USA. USA. Tel.:+1 617 642 0449; Fax: +1 617 726 7422; E-mail: shasha.li@mgh.harvard.edu.

Note: [1] These authors contributed equally to this work.

Abstract: BACKGROUND:Graded motor imagery (GMI) therapy is a neural rehabilitative physiotherapy that has been shown to alleviate the severity of complex regional pain syndrome, phantom limb pain and disability. OBJECTIVE:To identify neural networks associated with the use of graded mirror therapy (MT) while imagining hand movements. METHODS:We made a block-design functional magnetic resonance imaging study of MT included three experiments: (1) immobile unimanual MT (IU-MT), in which the right hand flexed and made a fist, which then remained immobile; (2) mobilization unimanual MT (MU-MT), in which the right hand performed a flexion-extension movement; and (3) mobilization bimanual MT (MB-MT), in which both hands performed a flexion-extension movement. When subjects started their hand movements, they gazed at the mirror and imagined the same movement behind the mirror. RESULTS:We discovered that the sensorimotor area of the left brain, superior temporal gyrus/middle temporal gyrus (STG/MTG) of the right brain and visual areas were activated by IU-MT. In MU-MT, only the STG/MTG was activated. Furthermore, MB-UT mostly activated the sensorimotor area and STG of the right brain. However, there were no brain areas activated by MU-MT compared with IU-MT or MB-MT; but, MB-MT activated more motor areas than IU-MT. Importantly, we determined that the level of mirror imagery was negatively correlated with signals in the mirror neuron system (MNS) and positively related with the signals in the sensorimotor areas. CONCLUSIONS:We suggest that graded MT might be a sequential therapeutic program that can enhance the sensorimotor cortex. The MNS might have an initiating role in graded MT. Thus, there is the possibility that graded MT is a helpful treatment strategy for the rehabilitation of dysfunctional patients.

Keywords: Graded motor imagery, cerebral activation, visual illusion, functional magnetic resonance imaging (fMRI), rehabilitation

DOI: 10.3233/NRE-210185

Journal: NeuroRehabilitation, vol. 49, no. 4, pp. 641-654, 2021