What question did this study set out to answer?

The study evaluates how corticospinal excitability interacts with endogenous pain modulation and psychological factors.

April 19, 2026Open Access

Exploring pain-motor dynamics: preliminary insights through exploration of descending inhibition and corticospinal excitability

ADArnaud DuportWestern University HDH. DevanneUniversité de Lille GLGuillaume LéonardUniversité de Sherbrooke

Puntos clave

The study evaluates how corticospinal excitability interacts with endogenous pain modulation and psychological factors.
Analyzed 21 pain-free participants' kinesiophobia and pain catastrophizing through questionnaires.
Applied conditioned pain modulation to assess endogenous pain modulation.
Employed transcranial magnetic stimulation to measure corticospinal excitability in specific muscles.
Found a significant correlation between deltoid input-output curve plateau and conditioned pain modulation responses.
Demonstrated strong negative correlation between the slope of FDI and conditioned pain modulation responses.
Identified that kinesiophobia influences the relationship between muscle excitability changes and pain modulation.

Resumen

Introduction Previous studies have linked endogenous pain modulation and corticospinal excitability (CSE), but methodological limitations and overlooking psychological factors may have constrained interpretations. This study aimed to evaluate the interaction between CSE excitability in different muscles and endogenous pain modulation, and to determine whether kinesiophobia and pain catastrophizing modulate this interaction. Methods Twenty-one pain-free participants completed questionnaires on kinesiophobia and pain catastrophizing. Conditioned pain modulation (CPM) was used to assess endogenous pain modulation. Transcranial magnetic stimulation was used to assess the pain-induced modulation in CSE excitability, focusing on slope, S 50 and the maximum response parameters of input-output curves (plateau) for the anterior deltoid (AD) and first dorsal interosseous (FDI) muscles, first in pain-free then in painful condition induced by the application of capsaicin cream to the shoulder. Results A significant correlation was found between the plateau of the AD input-output curves measured at baseline (pain-free condition) and CPM responses (r S = .56, p = 0.01), suggesting that higher maximal corticospinal output is associated with more effective endogenous pain modulation. Pain-induced changes in FDI slope and CPM responses were strongly correlated (r S = -.75, p 0.001), indicating that individuals with the most effective endogenous pain inhibition mechanisms were those with the greatest increase in CSE. Finally, kinesiophobia was found to alter the association between pain-induced changes in CSE in AD (S 50 shift) and CPM response, shedding new light on the influence of psychological factors on pain-induced CSE alterations and their link with descending pain inhibition. Discussion These findings underscore the complex interplay between corticospinal projections, pain modulation, and psychological factors, reinforcing the need for further investigation.

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