title: Cortical activity evoked by an acute painful tissue-damaging stimulus in healthy adult volunteers.
abstract: Everyday painful experiences are usually single events accompanied by tissue damage, and yet most experimental studies of cutaneous nociceptive processing in the brain use repeated laser, thermal, or electrical stimulations that do not damage the skin. In this study the nociceptive activity in the brain evoked by tissue-damaging skin lance was analyzed with electroencephalography (EEG) in 20 healthy adult volunteers (13 men and 7 women) aged 21-40 yr. Time-frequency analysis of the evoked activity revealed a distinct late event-related vertex potential (lance event-related potential, LERP) at 100-300 ms consisting of a phase-locked energy increase between 1 and 20 Hz (delta-beta bands). A pairwise comparison between lance and sham control stimulation also revealed a period of ultralate stronger desynchronization after lance in the delta band (1-5 Hz). Skin application of mustard oil before lancing, which sensitizes a subpopulation of nociceptors expressing the cation channel TRPA1, did not affect the ultralate desynchronization but reduced the phase-locked energy increase in delta and beta bands, suggesting a central interaction between different modalities of nociceptive inputs. Verbal descriptor screening of individual pain experience revealed that lance pain is predominantly due to Aδ fiber activation, but when individuals describe lances as C fiber mediated, an ultralate delta band event-related desynchronization occurs in the brain-evoked activity. We conclude that pain evoked by acute tissue damage is associated with distinct Aδ and C fiber-mediated patterns of synchronization and desynchronization of EEG oscillations in the brain.
authors: Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom. l.fabrizi@ucl.ac.uk
authors: Lorenzo
authors: L
authors: Fabrizi
authors: Gemma
authors: G
authors: Williams
authors: Amy
authors: A
authors: Lee
authors: Judith
authors: J
authors: Meek
authors: Rebeccah
authors: R
authors: Slater
authors: Sofia
authors: S
authors: Olhede
authors: Maria
authors: M
authors: Fitzgerald
mesh_terms: D000328:Adult; D001611:Beta Rhythm; D015220:Calcium Channels / Q000378:metabolism; D002540:Cerebral Cortex / Q000502:physiology*; D003700:Delta Rhythm; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D059225:Nociception / Q000502:physiology*; D009619:Nociceptors / Q000378:metabolism / Q000502:physiology; D012867:Skin / Q000166:cytology / Q000293:injuries / Q000294:innervation*; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels
keywords: brain; cortex; event-related potential; nociception; pain