Non-invasive motor cortex neuromodulation reduces secondary hyperalgesia and enhances activation of the descending pain modulatory network

Timothy J. Meeker, Michael L. Keaser, Shariq A. Khan, Rao P. Gullapalli, David A. Seminowicz, Joel D. Greenspan

Research output: Contribution to journalArticlepeer-review

Abstract

Central sensitization is a driving mechanism in many chronic pain patients, and manifests as hyperalgesia and allodynia beyond any apparent injury. Recent studies have demonstrated analgesic effects of motor cortex (M1) stimulation in several chronic pain disorders, yet its neural mechanisms remain uncertain. We evaluated whether anodal M1 transcranial direct current stimulation (tDCS) would mitigate central sensitization as measured by indices of secondary hyperalgesia. We used a capsaicin-heat pain model to elicit secondary mechanical hyperalgesia in 27 healthy subjects. In an assessor and subject-blind randomized, sham-controlled, crossover trial, anodal M1 tDCS decreased the intensity of pinprick hyperalgesia more than cathodal or sham tDCS. To elucidate the mechanism driving analgesia, subjects underwent fMRI of painful mechanical stimuli prior to and following induction of the pain model, after receiving M1 tDCS. We hypothesized that anodal M1 tDCS would enhance engagement of a descending pain modulatory (DPM) network in response to mechanical stimuli. Anodal tDCS normalized the effects of central sensitization on neurophysiological responses to mechanical pain in the medial prefrontal cortex, pregenual anterior cingulate cortex, and periaqueductal gray, important regions in the DPM network. Taken together, these results provide support for the hypothesis that anodal M1-tDCS reduces central sensitization-induced hyperalgesia through the DPM network in humans.

Original languageEnglish (US)
Article number467
JournalFrontiers in Neuroscience
Volume13
Issue numberMAY
DOIs
StatePublished - 2019
Externally publishedYes

Keywords

  • Bold FMRI
  • Event-related FMRI
  • Human
  • Motor cortex neuromodulation
  • Pain
  • Pain model
  • Secondary hyperalgesia
  • Transcranial direct current stimulation

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Non-invasive motor cortex neuromodulation reduces secondary hyperalgesia and enhances activation of the descending pain modulatory network'. Together they form a unique fingerprint.

Cite this