title: Does the insula tell our brain that we are in pain?
abstract: Current knowledge on pain-related cerebral networks has relied so far on stimulus-induced brain responses, but not on the analysis of brain activity during spontaneous pain attacks. In this case report, correlation between intracerebral field potentials and online sensations during spontaneously painful epileptic seizures suggests a crucial role of the insula in the development of subjective pain. Attacks originated from a very limited dysplasia located in the posterior third of the right insula and propagated to other areas of the pain matrix, including the parietal operculum and the midcingulate gyrus. Concomitant painful symptoms started on the left hand or the left foot and extended in a few seconds to the whole left side of the body, sparing the head. Continuous during the first seconds of the attack, the painful feeling evolved to throbbing and remained so until it progressively vanished, together with the spike discharge. Stimulation of the insula, but not of other pain matrix regions, induced pain identical to that of seizures. After thermocoagulation of the insular epileptic focus, a short, transient exacerbation of seizures with same painful features but different location was observed before a long-lasting and complete remission of the attacks. Although these preliminary data need to be confirmed, they strongly suggest that if the full pain experience involves the pain matrix network, the posterior insula seems to play a leading role in the triggering of this network and the resulting emergence of subjective pain experience.
authors.affiliation: Central Integration of Pain Unit - INSERM U879, Lyon, France Hospices Civils de Lyon, Hôpital Neurologique, Service de Neurologie Fonctionnelle et d'Epileptologie, Bron F-69677, France University Claude Bernard Lyon 1, Lyon F-69000, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Isnard
authors.forename: Michel
authors.initials: M
authors.lastname: Magnin
authors.forename: Julien
authors.initials: J
authors.lastname: Jung
authors.forename: François
authors.initials: F
authors.lastname: Mauguière
authors.forename: Luis
authors.initials: L
authors.lastname: Garcia-Larrea
mesh_terms: D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D004564:Electrocoagulation / Q000009:adverse effects; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000150:complications* / Q000209:etiology / Q000473:pathology; D005071:Evoked Potentials / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010146:Pain / Q000150:complications* / Q000473:pathology*; D013997:Time Factors; D055815:Young Adult