Title:
Not an Aspirin: No Evidence for Acute Anti-Nociception to Las
er-Evoked Pain After Motor Cortex rTMS in Healthy Humans.
Authors:
Bradley C; Perchet C; Lelekov-Boissard T; Magnin M; Garcia-Larrea L.
Institution Bradley,Claire. NEUROPAIN Team, Centre de Recherche en Neurosciences deLyon, Inserm U1028 – CNRS UMR5292, Universite Claude Bernard Lyon 1, Lyon, France. Electronic address: clairebradleyhartmann@gmail.com .Perchet,Caroline. NEUROPAIN Team, Centre de Recherche en Neurosciences de
Lyon, Inserm U1028 – CNRS UMR5292, Universite Claude Bernard Lyon 1, Lyon, France. Lelekov-Boissard,Taissia. NEUROPAIN Team, Centrede Recherche en Neurosciences de Lyon, Inserm U1028 – CNRSUMR5292, Universite Claude Bernard Lyon 1, Lyon, France. Magnin,Michel. NEUROPAIN Team, Centre de Recherche en Neurosciences de Lyon, Inserm U1028 – CNRS UMR5292, Universite Claude Bernard Lyon 1, Lyon, France. Garcia-Larrea,Luis. NEUROPAIN Team, Centre de Recherche en Neurosciences de Lyon, Inserm U1028 – CNRSUMR5292, Universite Claude Bernard Lyon 1, Lyon, France.
Title:
Not an Aspirin: No Evidence for Acute Anti-Nociception to Las
er-Evoked Pain After Motor Cortex rTMS in Healthy Humans.
Source:
Brain Stimulation. 9(1):48-57, 2016 Jan-Feb.
Abstract:
BACKGROUND: High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) has shown efficacy in relieving neuropathic pain. Whether its analgesic effect also applies to acute physiological nociception remains unclear due to previous contradictory findings.
OBJECTIVE:
To provide an in-depth investigation of the effects of motor cortex HF-rTMS on acute laser-evoked pain and excitability of nociceptive networks in healthy subjects.
METHODS:
Randomized, placebo-controlled, double-blind, cross-over study in
20 healthy participants. Laser heat stimuli at nociceptive threshold were
delivered to the right hand, allowing assessment of: (a) subjective pain
intensity and unpleasantness; (b) laser-evoked potentials (LEPs, 128
electrodes) and their source model; (c) sympathetic skin responses, and
(d) spino-thalamic pathway excitability. Data were collected before and
20minutes after a session of neuro-navigated 20Hz rTMS to the contralateral motor cortex.
RESULTS:
Subjective pain reports to thermal laser pulses, amplitude of late cortical potentials and sympathetic skin responses were decreased after cortical stimulation, to a similar extent whether it was active or placebo. Early cortical potentials and nociceptive network excitability remained identical before and after rTMS, as did anatomical sources of LEPs.
CONCLUSIONS:
Our results do not provide evidence for a genuine anti-nociceptive effect of rTMS on acute physiological pain. We suggest that motor cortex rTMS may act upon high-order networks linked to the emotional and cognitive appraisal of chronic pain, and/or modulate pathologically sensitized networks, rather than change the physiological transmission within an intact nervous system. Such dichotomy is reminiscent of that observed with most drugs used for neuropathic pain.
Copyright:
2015 Elsevier Inc. All rights reserved. Publication Type Journal Article. Randomized Controlled Trial. Research Support, Non-U.S. Gov’t.
