title: Dynamic assessment of the right lateral frontal cortex response to painful stimulation.
abstract: The lateral surface of the right frontal lobe has a relevant role in modulating behavioral responses to aversive stimuli and may significantly influence pain experience. Imaging studies suggest that this modulatory role is multifaceted, but no studies have assessed the regional specialization of this cortex on the basis of its response dynamics during pain processing. We aimed to investigate functional specialization within the right lateral frontal cortex using a dynamic fMRI approach. Brain responses to a mechanical painful stimulus and a preceding anticipatory cue (auditory tone) were assessed in 25 healthy subjects. Functional data were decomposed into 15 sequential activation maps covering the full anticipation-painful stimulation cycle using a finite impulse response (FIR) analysis approach. Movie sequences showing the temporal evolution of brain activation illustrate the findings. A region involving premotor-prefrontal cortices was activated soon after the anticipatory cue and showed a significant correlation with both anterior cingulate cortex activation and subjective pain ratings. The frontal operculum also showed a significant anticipatory response, but the most robust activation followed painful stimulation onset and was strongly correlated with insula activation. The anterior prefrontal cortex showed full activation during late painful stimulation and was negatively correlated with pain unpleasantness. In conclusion, different elements within the right lateral frontal cortex showed distinct activation dynamics in response to painful stimulation, which would suggest relevant regional specialization during pain processing. These findings are congruent with the broad functional role of the right frontal cortex and its influence on crucial aspects of human behavior.
authors.affiliation: Institut d'Alta Tecnologia-PRBB, CRC Hospital del Mar, Barcelona, Spain.
authors.forename: Marina
authors.initials: M
authors.lastname: López-Solà
authors.forename: Jesus
authors.initials: J
authors.lastname: Pujol
authors.forename: Rosa
authors.initials: R
authors.lastname: Hernández-Ribas
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Héctor
authors.initials: H
authors.lastname: Ortiz
authors.forename: Carles
authors.initials: C
authors.lastname: Soriano-Mas
authors.forename: Joan
authors.initials: J
authors.lastname: Deus
authors.forename: José M
authors.initials: JM
authors.lastname: Menchón
authors.forename: Julio
authors.initials: J
authors.lastname: Vallejo
authors.forename: Narcís
authors.initials: N
authors.lastname: Cardoner
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000367:Age Factors; D001307:Auditory Perception / Q000502:physiology; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D010812:Physical Stimulation; D011312:Pressure; D013997:Time Factors; D014741:Video Recording