title: Unravelling the effect of experimental pain on the corticomotor system using transcranial magnetic stimulation and electroencephalography.
abstract: The interaction between pain and the motor system is well-known, with past studies showing that pain can alter corticomotor excitability and have deleterious effects on motor learning. The aim of this study was to better understand the cortical mechanisms underlying the interaction between pain and the motor system. Experimental pain was induced on 19 young and healthy participants using capsaicin cream, applied on the middle volar part of the left forearm. The effect of pain on brain activity and on the corticomotor system was assessed with electroencephalography (EEG) and transcranial magnetic stimulation (TMS), respectively. Compared to baseline, resting state brain activity significantly increased after capsaicin application in the central cuneus (theta frequency), left dorsolateral prefrontal cortex (alpha frequency), and left cuneus and right insula (beta frequency). A pain-evoked increase in the right primary motor cortex (M1) activity was also observed (beta frequency), but only among participants who showed a reduction in corticospinal output (as depicted by TMS recruitment curves). These participants further showed greater beta M1-cuneus connectivity than the other participants. These findings indicate that pain-evoked increases in M1 beta power are intimately tied to changes in the corticospinal system, and provide evidence that beta M1-cuneus connectivity is related to the corticomotor alterations induced by pain. The differential pattern of response observed in our participants suggest that the effect of pain on the motor system is variable from on individual to another; an observation that could have important clinical implications for rehabilitation professionals working with pain patients.
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.|Research Centre on Aging, CIUSSS de l'Estrie-CHUS, 1036, rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada.
authors.forename: Marylie
authors.initials: M
authors.lastname: Martel
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.|Research Centre on Aging, CIUSSS de l'Estrie-CHUS, 1036, rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada.
authors.forename: Marie-Philippe
authors.initials: MP
authors.lastname: Harvey
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.|Research Centre on Aging, CIUSSS de l'Estrie-CHUS, 1036, rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada.
authors.forename: Francis
authors.initials: F
authors.lastname: Houde
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.|Department of Surgery, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Balg
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.|Department of Surgery, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Goffaux
authors.affiliation: Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, J1H 5N4, Canada. guillaume.leonard2@usherbrooke.ca.|Research Centre on Aging, CIUSSS de l'Estrie-CHUS, 1036, rue Belvédère Sud, Sherbrooke, QC, J1H 4C4, Canada. guillaume.leonard2@usherbrooke.ca.
authors.forename: Guillaume
authors.identifier: http://orcid.org/0000-0002-3625-3072
authors.initials: G
authors.lastname: Léonard
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002211:Capsaicin / Q000009:adverse effects; D004569:Electroencephalography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology*; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
chemical_list: D002211:Capsaicin
keywords: Corticospinal tract; Electroencephalography; Experimental pain; Functional connectivity; Motor cortex; Pain; Recruitment curves; Transcranial magnetic stimulation