Rehabilitation Effects of Fatigue-Controlled Treadmill Training After Stroke: A Rat Model Study

Simultaneous high-definition transcranial direct current stimulation and robot-assisted gait training in stroke patients

This study investigates whether simultaneous high-definition transcranial direct current stimulation (HD-tDCS) enhances the effects of robot-assisted gait training in stroke patients. Twenty-four participants were randomly allocated to either the robot-assisted gait training with real HD-tDCS group (real HD-tDCS group) or robot-assisted gait training with sham HD-tDCS group (sham HD-tDCS group). Over four weeks, both groups completed 10 sessions. The 10 Meter Walk Test, Timed Up and Go, Functional Ambulation Category, Functional Reach Test, Berg Balance Scale, Dynamic Gait Index, Fugl-Meyer Assessment, and Korean version of the Modified Barthel Index were conducted before, immediately after, and one month after the intervention. The real HD-tDCS group showed significant improvements in the 10 Meter Walk Test, Timed Up and Go, Functional Reach Test, and Berg Balance Scale immediately and one month after the intervention, compared with before the intervention. Significant improvements in the Dynamic Gait Index and Fugl-Meyer Assessment were also observed immediately after the intervention. The sham HD-tDCS group showed no significant improvements in any of the tests. Application of HD-tDCS during robot-assisted gait training has a positive effect on gait and physical function in chronic stroke patients, ensuring long-term training effects. Our results suggest the effectiveness of HD-tDCS as a complementary tool to enhance robotic gait rehabilitation therapy in chronic stroke patients.

Motor Rehabilitation Provides Modest Functional Benefits After Intracerebral Hemorrhage: a Systematic Review and Meta-Analysis of Translational Rehabilitation Studies

Few certainties exist regarding the optimal type, timing, or dosage of rehabilitation after stroke. Despite differing injury mechanisms and recovery patterns following ischemic and hemorrhagic stroke, most translational stroke research is conducted after ischemia. As we enter the era of personalized medicine, exploring subtype-specific treatment efficacy is essential to optimizing recovery. Our objective was to characterize common rehabilitation interventions used after in vivo preclinical intracerebral hemorrhage (ICH) and assess the impact of post-ICH rehabilitation (vs. no-rehabilitation) on recovery of motor function. Following PRISMA guidelines, a systematic review (Academic Search Complete, CINAHL, EMBASE, Medline, PubMed Central) identified eligible articles published up to December 2022. Risk of bias (SYRCLE) and study quality (CAMARADES) were evaluated, and random-effects meta-analysis was used to assess treatment efficacy in recovery of forelimb and locomotor functions. Thirty articles met inclusion criteria, and 48 rehabilitation intervention groups were identified. Most used collagenase to model striatal ICH in young, male rodents. Aerobic exercise, enriched rehabilitation, and constraint-induced movement therapy represented ~ 70% of interventions. Study quality was low (median 4/10, range 2-8), and risk of bias was unclear. Rehabilitation provided modest benefits in skilled reaching, spontaneous impaired forelimb use, and locomotor function; however, effects varied substantially by endpoint, treatment type, and study quality. Rehabilitation statistically improves motor function after preclinical ICH, but whether these effects are functionally meaningful is unclear. Incomplete reporting and variable research quality hinder our capacity to analyze and interpret how treatment factors influence rehabilitation efficacy and recovery after ICH.

A common neuronal ensemble in nucleus accumbens regulates pain-like behaviour and sleep

A comorbidity of chronic pain is sleep disturbance. Here, we identify a dual-functional ensemble that regulates both pain-like behaviour induced by chronic constrictive injury or complete Freund's adjuvant, and sleep wakefulness, in the nucleus accumbens (NAc) in mice. Specifically, a select population of NAc neurons exhibits increased activity either upon nociceptive stimulation or during wakefulness. Experimental activation of the ensemble neurons exacerbates pain-like (nociceptive) responses and reduces NREM sleep, while inactivation of these neurons produces the opposite effects. Furthermore, NAc ensemble primarily consists of D1 neurons and projects divergently to the ventral tegmental area (VTA) and preoptic area (POA). Silencing an ensemble innervating VTA neurons selectively increases nociceptive responses without affecting sleep, whereas inhibiting ensemble-innervating POA neurons decreases NREM sleep without affecting nociception. These results suggest a common NAc ensemble that encodes chronic pain and controls sleep, and achieves the modality specificity through its divergent downstream circuit targets.

Corticostriatal Projections Relying on GABA Levels Mediate Exercise-Induced Functional Recovery in Cerebral Ischemic Mice

Stroke is a neurological disorder characterized by high disability and death worldwide. The occlusion of the middle cerebral artery (MCAO) supplying the cortical motor regions and its projection pathway regions can either kill the cortical neurons or block their projections to the spinal cord and subcortical structure. The cerebral cortex is the primary striatal afferent, and the medium spiny neurons of the striatum have been identified as the major output neurons projecting to the substantia nigra and pallidum. Thus, disconnection of the corticostriatal circuit often occurs in the model of MCAO. In this study, we hypothesize that striatal network dysfunction in cerebral ischemic mice ultimately modulates the activity of striatal projections from cortical neurons to improve dysfunction during exercise training. In this study, we observed that the corticostriatal circuit originating from glutamatergic neurons could partially medicate the improvement of motor and anxiety-like behavior in mice with exercise. Furthermore, exercising or activating a single optogenetic corticostriatal circuit can increase the striatal gamma-aminobutyric acid (GABA) level. Using the GABA-A receptor antagonist, bicuculline, we further identified that the striatal glutamatergic projection from the cortical neurons relies on the GABAergic synapse's activity to modulate exercise-induced functional recovery. Overall, those results reveal that the dorsal striatum-projecting subpopulation of cortical glutamatergic neurons can influence GABA levels in the striatum, playing a critical role in modulating exercise-induced improvement of motor and anxiety-like behavior.

Evaluation of Central Fatigue in Post-stroke Rehabilitation: A Pilot Study

Central fatigue induced by excessive rehabilitation training would limit motor activity or even damage the post-stroke motor function recovery. However, the central fatigue progress during training is unclear and ignored in post-stroke rehabilitation. In this study, we tried to investigate the changes in central fatigue with fractal dimension (FD) of electromyography (EMG) at different peripheral fatigue levels based on the intracerebral haemorrhage (ICH) model. Ten Sprague-Dawley rats with ICH and EMG electrodes implantation were randomly distributed into two groups: the forced training (FOR) group with exhausted peripheral fatigue level (n=5) and fatigue-controlled (FAT) group (n=5) with peripheral fatigue constrained in moderate level. A higher central fatigue level was found in the FOR group (P<0.0001), and the central fatigue could be alleviated by peripheral fatigue-based modulation in the FAT group. The FAT group with less central fatigue achieved significantly better motor function recovery (P<0.0001), and it might be related to the recovery in the ability of motor unit recruitments.