Journal article

Publication year: 2020

Pages: 1035-1042

Journal: Experimental Brain Research

Volume number: 238

Issue number: 4

ISSN: 0014-4819

eISSN: 1432-1106

Open access status: Hybrid

DOI Link: https://doi.org/10.1007/s00221-020-05779-x

Publisher: Springer

Abstract: 
In homeostasis, somatosensory C fibre afferents are hypothesised to mediate input to the brain about interactions with external stimuli and sympathetic efference provides the output that regulates bodily functions. We aimed to test this hypothesis and whether different types of innocuous somatosensory input have differential effects. Healthy volunteers performed a muscle fatigue (hand-grip) task to exhaustion, which produces increased muscle sympathetic nerve activity (MSNA), as measured through microneurography. Participants completed the muscle fatigue task without concurrent cutaneous sensory stimulation (control) or we applied skin warming (heat pack) as a C fibre stimulation, slow brush stroking as C and A beta fibre stimulation, or vibration as A beta fibre stimulation, to the participant's forearm. We also measured heart rate, the duration of the hand-grip task, and ratings of pain at the end of the task. Concurrent skin warming showed increased MSNA compared to the other conditions. Tactile stimuli (brushing, vibration) were not significantly different to the control (no intervention) condition. Warming increased the pain from the muscle contraction, whereas the tactile stimuli did not. We interpret the effect of warming on MSNA as providing relevant afferent information during muscle contraction, which needed to be counteracted via vasoconstriction to maintain homeostasis. Brushing and vibration were less homeostatically relevant stimuli for the muscle contraction and hence had no significant effect. The findings add sensory specificity to our current understanding of homeostatic regulation through somatosensory afferent and sympathetic efferent pathways.

Harvard Citation style: Ackerley, R., Sverrisdottir, Y., Birklein, F., Elam, M., Olausson, H. and Kraemer, H. (2020) Cutaneous warmth, but not touch, increases muscle sympathetic nerve activity during a muscle fatigue hand-grip task, Experimental Brain Research, 238(4), pp. 1035-1042. https://doi.org/10.1007/s00221-020-05779-x

APA Citation style: Ackerley, R., Sverrisdottir, Y., Birklein, F., Elam, M., Olausson, H., & Kraemer, H. (2020). Cutaneous warmth, but not touch, increases muscle sympathetic nerve activity during a muscle fatigue hand-grip task. Experimental Brain Research. 238(4), 1035-1042. https://doi.org/10.1007/s00221-020-05779-x