title: Lasting depression in corticomotor excitability associated with local scalp cooling.
abstract: In this study, we investigated the effect of local scalp cooling on corticomotor excitability with transcranial magnetic simulation (TMS). Participants (healthy male adults, n=12) were first assessed with TMS to derive baseline measure of excitability from motor evoked potentials (MEPs) using the right first dorsal interosseous as the target muscle. Then, local cooling was induced on the right hemi-scalp (upper frontal region ∼ 15 cm(2)) by means of a cold wrap. The cooling was maintained for 10-15 min to get a decrease of at least 10°C from baseline temperature. In the post-cooling period, both scalp temperature and MEPs were reassessed at specific time intervals (i.e., T0, T10, T20 and T30 min). Scalp surface temperatures dropped on average by 12.5°C from baseline at T0 (p<0.001) with partial recovery at T10 (p<0.05) and full recovery at T20. Parallel analysis of post-cooling variations in MEP amplitude revealed significant reductions relative to baseline at T0, T10 and T20. No concurrent change in MEP latency was observed. A secondary control experiment was performed in a subset of participants (n=5) to account for the mild discomfort associated with the wrapping procedure without the cooling agent. Results showed no effect on any of the dependent variables (temperature, MEP amplitude and latency). To our knowledge, this report provides the first neurophysiological evidence linking changes in scalp temperature with lasting changes in corticomotor excitability.
authors.affiliation: School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ontario, Canada; Bruyère Research Institute, Ottawa, Ontario, Canada,. Electronic address: francois.tremblay@uottawa.ca.
authors.forename: François
authors.initials: F
authors.lastname: Tremblay
authors.affiliation: School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ontario, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Remaud
authors.affiliation: School of Electrical Engineering and Computer Science, Faculty of Engineering, University of Ottawa, Ontario, Canada.
authors.forename: Abeye
authors.initials: A
authors.lastname: Mekonnen
authors.affiliation: School of Electrical Engineering and Computer Science, Faculty of Engineering, University of Ottawa, Ontario, Canada.
authors.forename: Shiva
authors.initials: S
authors.lastname: Gholami-Boroujeny
authors.affiliation: Biomedical Sciences Program Faculty of Science, University of Ottawa, Ontario, Canada.
authors.forename: Karl-Édouard
authors.initials: KÉ
authors.lastname: Racine
authors.affiliation: School of Electrical Engineering and Computer Science, Faculty of Engineering, University of Ottawa, Ontario, Canada.
authors.forename: Miodrag
authors.initials: M
authors.lastname: Bolic
mesh_terms: D000328:Adult; D001831:Body Temperature; D019054:Evoked Potentials, Motor; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D012535:Scalp / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Motor cortex; Motor evoked potentials; Scalp cooling; Transcranial magnetic stimulation