Low-Frequency Repetitive Transcranial Magnetic Stimulation Restores Dynamic Functional Connectivity in Subcortical Stroke

Abstract

Background and Purpose: Strokes consistently result in brain network dysfunction. Previous studies have focused on the resting-state characteristics over the study period, while dynamic recombination remains largely unknown. Thus, we explored differences in dynamics between brain networks in patients who experienced subcortical stroke and the effects of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) on dynamic functional connectivity (dFC).Methods: A total of 41 patients with subcortical stroke were randomly divided into the LF-rTMS (n = 23) and the sham stimulation groups (n = 18). Resting-state functional MRI data were collected before (1 month after stroke) and after (3 months after stroke) treatment; a total of 20 age- and sex-matched healthy controls were also included. An independent component analysis, sliding window approach, and k-means clustering were used to identify different functional networks, estimate dFC matrices, and analyze dFC states before treatment. We further assessed the effect of LF-rTMS on dFCs in patients with subcortical stroke.Results: Compared to healthy controls, patients with stroke spent significantly more time in state I [p = 0.043, effect size (ES) = 0.64] and exhibited shortened stay in state II (p = 0.015, ES = 0.78); the dwell time gradually returned to normal after LF-rTMS treatment (p = 0.015, ES = 0.55). Changes in dwell time before and after LF-rTMS treatment were positively correlated with changes in the Fugl–Meyer Assessment for Upper Extremity (pr = 0.48, p = 0.028). Moreover, patients with stroke had decreased dFCs between the sensorimotor and cognitive control domains, yet connectivity within the cognitive control network increased. These abnormalities were partially improved after LF-rTMS treatment.Conclusion: Abnormal changes were noted in temporal and spatial characteristics of sensorimotor domains and cognitive control domains of patients who experience subcortical stroke; LF-rTMS can promote the partial recovery of dFC. These findings offer new insight into the dynamic neural mechanisms underlying effect of functional recombination and rTMS in subcortical stroke.Registration:http://www.chictr.org.cn/index.aspx, Unique.identifier: ChiCTR1800019452.

Dynamic brain activity states of memory impairment in stroke patients with varying motor outcomes

“…However, the brain's activity is inherently dynamic. This temporal dynamic variability is closely related to neural networks functionality and can reveal fluctuations in network interactions (Allen et al, 2014) and patterns of recurrent brain activity that are beyond the scope of static analyses (Liegeois et al, 2017;Qin et al, 2021). The findings of this study indicate that the dynamic neural properties metrics have greater potential than the static characteristics for diagnosing and predicting cerebral neurological function states in the stroke patients.…”

Evidence of rTMS for Motor or Cognitive Stroke Recovery: Hype or Hope?

“…HF rTMS, LF-HF rTMS, LF rTMS long ITI rTMS, paired associative stimulation, or short ITI rTMS was associated with improved upper limb muscle synergies in 782 patients from 17 studies (SMD, 1.20 [95% CI, 0.73–1.68]; I 2 , 88%). 17–32…”

“…HF rTMS, LF-HF rTMS, LF rTMS long ITI rTMS, paired associative stimulation, or short ITI rTMS was associated with improved upper limb muscle synergies in 782 patients from 17 studies (SMD, 1.20 [95% CI, 0.73-1.68]; I 2 , 88%). [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] There was no statistically significant effect of iTBS or LF rTMS on lower limb muscle synergies in 168 patients from 5 studies (SMD, −0.19 [95% CI, −0.80 to 0.42]; I 2 , 74%). 26,[33][34][35][36] HF rTMS, iTBS, or LF rTMS was associated with improved muscle strength in 261 patients from seven studies (SMD, 0.52 [95% CI, 0.04-1.00]; I 2 , 69%).…”

Alterations of insular dynamic functional connectivity and psychological characteristics in unmedicated bipolar depression patients with a recent suicide attempt

“…A recent study indicated that the changes in frontostriatal FC would accompany suicidality reductions following transcranial magnetic stimulation (TMS) in patients with comorbid post-traumatic stress disorder and depression (Barredo et al, 2021). Meanwhile, researchers have also found that low-frequency repetitive TMS can restore the dFC of sensorimotor and cognitive control domains in patients with subcortical stroke (Qin et al, 2021). Concordant with another study (Philip, Barredo, Aiken, & Carpenter, 2018), these findings may suggest that TMS modulates and potentially normalizes functional relationships between neural networks were associated with clinical improvement.…”