Discussion
stroke, depression, spasticity, infarction
STROKE, CORTEX, INFARCTION
This reanalysis of a home-based TR training trial showed that the dynamic alteration patterns in regional intrinsic neural activity and degree centrality were different between the TR group and CR group. To the best of our knowledge, the current longitudinal study is the first to explore dynamic spontaneous neural activity and functional connectivity variability with TR training in stroke patients. Our study showed that dALFF alterations in the right precuneus, the bilateral PreCG, and the right IPL were significantly different between groups. The results revealed that the dALFF value in the right IPL was significantly increased within the TR group after 12 weeks of TR training. In contrast, significantly increased dALFF values in the right cerebellum anterior lobe and the left RG were observed within the CR group. After follow-up, we found that dALFF values in the right IPL, right PreCG, right MFG, and right MTG were significantly increased within the TR group relative to the CR group. Regarding dReHo, we found that dReHo values in the right precuneus and the left MTG significantly increased within the TR group after TR training and follow-up, respectively. In the analyses of dDC, brain regions of the left CG, the right MFG and the left precuneus showed significantly increased functional connectivity with the whole brain and the other brain regions in the TR group compared with the CR group. Furthermore, a relationship was observed between the altered dALFF variability in the left PreCG and FMA changes from baseline to week 12 in the TR group. These findings may provide some theoretical basis for the neural mechanism of TR training to improve the motor function of stroke patients and may extend our understanding of dynamic functional reorganization during the rehabilitation of stroke patients.A previous study reported that the TR group showed significantly increased resting-state functional connectivity between bilateral PreCG areas at the end of rehabilitation (The PreCG is always the target brain location in noninvasive neuromodulatory techniques, such as rTMS and tDCS, which have potential for clinical utility in neurorehabilitation. After stroke, a series of functional reorganization changes occur that may result in reduced excitability in damaged brain regions and increased excitability in the homotopic regions of the undamaged contralateral hemisphere (Similarly, tDCS modulated neuroplasticity by long-term potentiation and long-term depression resulting from synaptic strengthening or weakening to maintain the balance between hemispheres (In this study, we demonstrated that the patients in the TR group showed significantly increased dALFF, dReHo and dD discrepancies in the precuneus, implying that the dynamic regional brain activity and functional connectivity in the precuneus were significantly heightened after TR training. The precuneus has extensive connectivity to cortical (the medial parietal cortex, the inferior and superior parietal lobules, the prefrontal cortex, the premotor area, the supplementary motor area, We also observed significant differences between the groups in the nonprimary sensorimotor network (SMN) areas, such as the MFG, MTG, IPS, RG and CG, which belong to the default mode network (DMN) and frontal-parietal network (FPN). Changes in neural activity of the DMN are likely to be related to enhanced neural function in cognitive and emotional control (In the current study, to explore whether the effects of TR on the increased dynamic dALFF variability in the left PreCG only occurred because participants in the TR group received more rehabilitation exposure, we evaluated the effects with variables for the number of treatment sessions and OT/PT and ETNS durations entered as covariates to control the potential confounding effects. The results showed that the differences in rehabilitation exposure had no effects on TR in the increased dynamic dALFF variability in the left PreCG for stroke patients, or that the effects were not large enough to be detected (for the change in increased dynamic dALFF variability in the left PreCG: the treatment sessions, Our study has several limitations. First, due to the small sample size of each group and the heterogeneity in hemispheres of infarction and lesion locations, it was difficult for us to further conduct subgroup analyses to determine the influences of locus of stroke on dynamic regional intrinsic neural activity and functional connectivity variability among patients in the TR group. Second, we aimed to explore the effects of the home-based TR approach on dynamic metrics and functional connectivity by calculating the main effect of group and the interaction of group × time; thus, we did not conduct analyses to assess the main effect of time. Third, because we assessed the regional spontaneous neural activity at the voxel level, it might be easier to detect the correlations between changed dynamic indicators and motor function if we utilized more refined assessments to evaluate motor function, such as grip strength, the action research arm test, the degree of spasticity and the range of motion of joints.