Characteristic of motor-related cortical network during stimulating at the affected or bilateral limbs of stroke patients by acupuncture

Background: The compensatory pattern between the two hemispheres after stroke has been the focus of research. Some evidence suggests bilateral stimulation more effectively engages networks across both hemispheres compared to the affected side only. Objectives: To explore whether the stimulating at bilateral limbs of stroke patients by acupuncture may better engage compensatory reorganization between the hemispheres compared to stimulating at the hemiplegic limb. Methods: Conscious patients with hemiplegia were screened. Brain activity was assessed by the functional near-infrared spectroscopy(fNIRS) in three states: no treatment, acupuncture on the affected side, and then acupuncture on both sides. Brain activation and directed functional connectivity(FC) was analyzed between the two acupuncture strategies. Results: Acupuncture of bilateral limbs resulted in stronger activation in the primary motor cortex(M1) of the ipsilesional hemisphere than acupuncture of the affected side only. And no significantly enhanced activation of the contralesional hemisphere was observed after acupuncture on the healthy limb. Besides, the FCs from the ipsilesional premotor cortex to the contralesional sensory-related area were significantly enhanced, and the FCs from the sensory area to motor area within the ipsilesional hemisphere were also significantly enhanced. Additionally, FCs from contralesional M1 to ipsilesional motor area were attenuated. Conclusion: Stimulating at bilateral limbs by acupuncture could lead to greater brain network remodeling in the motor-related areas compared to stimulating solely at the affected side, and not through more stimulation.