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Objective: Corticospinal inhibitory mechanisms are relevant to functional recovery but remain poorly understood after spinal cord injury (SCI). Post-injury characteristics of contralateral silent period (CSP), a measure of corticospinal inhibition evaluated using transcranial magnetic stimulation (TMS), is inconsistent in literature. We envisioned that investigating CSP across muscles with varying degrees of weakness may be a reasonable approach to resolve inconsistencies and elucidate the relevance of corticospinal inhibition for upper extremity function following SCI.
Methods: We studied 27 adults with chronic C1-C8 SCI (age 48.8 ± 16.1 years, 3 females) and 16 able-bodied participants (age 33.2 ± 11.8 years, 9 females). CSP characteristics were assessed across biceps (muscle power = 3-5) and triceps (muscle power = 1-3) representing stronger and weaker muscles, respectively. We assessed functional abilities using the Capabilities of the Upper Extremity Test (CUE-T).
Results: Participants with chronic SCI had prolonged CSPs for biceps but delayed and diminished CSPs for triceps compared to able-bodied participants. Early-onset CSPs for biceps and longer, deeper CSPs for triceps correlated with better CUE-T scores.
Conclusions: Corticospinal inhibition is pronounced for stronger biceps but diminished for weaker triceps muscle in SCI indicating innervation relative to the level of injury matters in the study of CSP.
Significance: Nevertheless, corticospinal inhibition or CSP holds relevance for upper extremity function following SCI.
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http://dx.doi.org/10.1016/j.clinph.2024.02.026 | DOI Listing |
Exp Brain Res
September 2025
Monash Neuromodulation Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia.
This study aimed to investigate the corticospinal drive modulation to Agonist and Antagonist arm muscles following Strength training and detraining, as neural adaptations are critical for early strength gains. Seventeen healthy, untrained young adults underwent four weeks of unilateral dumbbell curl training (60-80% of one-repetition maximum) followed by four weeks of detraining. Transcranial magnetic stimulation (TMS) assessed corticospinal excitability and inhibition across multiple intensities (100-200% rMT).
View Article and Find Full Text PDFEur J Appl Physiol
August 2025
Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University Exercise Neuroplasticity Research Unit, Monash University, PO Box 527, Frankston, Melbourne, VIC, 3199, Australia.
Purpose: The acute neurophysiological responses to resistance training (RT), particularly in corticospinal and reticulospinal pathways, remain unclear. This study investigated the effects of different RT modalities on these pathways.
Methods: Thirty-six RT-naive participants (10 males, 2 females per group) were randomly assigned to metronome-paced RT (MP-RT), self-paced RT (SP-RT), or a control group.
Sci Rep
August 2025
Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM-Juriquilla, Querétaro, Mexico.
The sensorimotor cortex is crucial for learning and executing new movements with precision. It selectively modulates sensory information flow and represents motor information in a spatially organized manner. The pyramidal system is made up of layer 5 pyramidal tract neurons (PTNs), which are organized into populations with distinct morphological, genetic and functional properties.
View Article and Find Full Text PDFScand J Med Sci Sports
September 2025
Faculty of Kinesiology, University of Calgary, Calgary, Canada.
Pain can impair exercise performance, but its influence on motor control, in particular the effect of robust experimental pain on the timecourse of corticomotor responses throughout prolonged, exhaustive cycling, remains unclear. We tested the hypothesis that an augmented experimental pain intervention applied to exercising and non-exercising limbs would modulate neuromuscular function, corticospinal excitability and inhibition, and exacerbate perceptual and cardiorespiratory responses to exercise. Ten healthy adults (two females) completed three single-leg cycling sessions at 60% peak power output to failure: without experimental pain (CTRL), with intermittent occlusions applied to the resting leg (CONTRA), and with occlusions upon the exercising leg (IPSI).
View Article and Find Full Text PDFMult Scler Relat Disord
August 2025
Gazi University Faculty of Medicine, Department of Neurology, Ankara, Turkey; Gazi University Faculty of Medicine, Department of Neurology, Clinical Neurophysiology Division, Ankara, Turkey.
Background: Radiologically isolated syndrome (RIS) is a preclinical stage of multiple sclerosis, characterized by demyelinating lesions on MRI. Transcranial magnetic stimulation (TMS) can detect corticospinal dysfunction associated with demyelination and neuronal loss.
Objective: This study aimed to investigate motor cortical excitability in RIS using TMS and explore its relationship with cognition, fatigue and MRI lesion characteristics.