title: Processing of nociceptive input from posterior to anterior insula in humans.
abstract: Previous brain imaging studies have shown robust activations in the insula during nociceptive stimulation. Most activations involve the posterior insular cortex but they can cover all insular gyri in some fMRI studies. However, little is known about the timing of activations across the different insular sub-regions. We report on the distribution of intracerebrally recorded nociceptive laser evoked potentials (LEPs) acquired from the full extent of the insula in 44 epileptic patients. Our study shows that both posterior and anterior subdivisions of the insular cortex respond to a nociceptive heat stimulus within a 200-400 ms latency range. This nociceptive cortical potential occurs firstly, and is larger, in the posterior granular insular cortex. The presence of phase reversals in LEP components in both posterior and anterior insular regions suggests activation of distinct, presumably functionally separate, sources in the posterior and anterior parts of the insula. Our results suggest that nociceptive input is first processed in the posterior insula, where it is known to be coded in terms of intensity and anatomical location, and then conveyed to the anterior insula, where the emotional reaction to pain is elaborated.
authors.affiliation: INSERM, U1028, Central Integration of Pain Unit, Neuroscience Research Center, Bron, F-69677, France; Claude Bernard University Lyon 1, Lyon, F-69000, France.
authors.forename: Maud
authors.initials: M
authors.lastname: Frot
authors.forename: Isabelle
authors.initials: I
authors.lastname: Faillenot
authors.forename: François
authors.initials: F
authors.lastname: Mauguière
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002533:Cerebral Angiography; D002540:Cerebral Cortex / Q000000981:diagnostic imaging / Q000502:physiology*; D004567:Electrodes, Implanted; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007834:Lasers / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009415:Nerve Net; D059225:Nociception / Q000502:physiology*; D055815:Young Adult
keywords: humans; insula; intracerebral recordings; laser-evoked potentials; pain