title: Repetitive transcranial magnetic stimulation of dorsolateral prefrontal cortex increases tolerance to human experimental pain.
abstract: Dorsolateral prefrontal cortex (DLPFCx) has been implicated in pain perception and in a pain modulation pathway. However, the precise participation of this region is not completely understood. The aim of this study was to evaluate whether 1 Hz rTMS of DLPFCx modifies threshold and tolerance in experimental pain. The effect of 1 Hz rTMS during 15 min at 100% motor threshold was tested in one hundred and eighty right-handed healthy volunteers, using a parallel-group stimulation design. The stimulation sites were right or left DLPFCx, right or left motor cortex, vertex or sham. rTMS was applied in two experimental contexts: (1) To evaluate its transitory effect (interference or facilitation) during cold pressor threshold (CPTh) and tolerance (CPTt) and (2) to evaluate its long-term effect by stimulating before CPTh, CPTt, pain heat thermal threshold, pain pressure threshold and tolerance. During rTMS of right DLPFCx, an increase in left hand CPTt (mean +/- SD; 17.63 s +/- 5.58 to 30.94 s +/- 14.84, P < 0.001) and in right hand CPTt (18.65 s +/- 6.47 to 26.74 s +/- 11.85, P < 0.001) were shown. No other stimulation site modified any of the pain measures during or after rTMS. These results show that 1 Hz rTMS of right DLPFCx has a selective effect by increasing pain tolerance and also sustains a right hemisphere preference in pain processing.
authors.affiliation: Instituto Nacional de Psiquiatría Ramón de la Fuente, Dirección de Investigaciones en Neurociencias (Lab. Neurofisiología Integrativa). Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, Del. Tlalpan, México, D.F. México. agraff@imp.edu.mx
authors.forename: Ariel
authors.initials: A
authors.lastname: Graff-Guerrero
authors.forename: Jorge
authors.initials: J
authors.lastname: González-Olvera
authors.forename: Ana
authors.initials: A
authors.lastname: Fresán
authors.forename: Diana
authors.initials: D
authors.lastname: Gómez-Martín
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Méndez-Núñez
authors.forename: Francisco
authors.initials: F
authors.lastname: Pellicer
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008280:Magnetics; D008297:Male; D059408:Pain Management; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology / Q000528:radiation effects*; D017397:Prefrontal Cortex / Q000503:physiopathology* / Q000528:radiation effects