The posterior insular-opercular cortex: an access to the brain networks of thermosensory and nociceptive processes?

Publication date: Available online 29 November 2018Source: Neuroscience LettersAuthor(s): R. Peyron, C. FauchonAbstractIn spite of systematic investigations, the existence of a specific cortex that could encode for the intensities of somatosensory stimuli, including within nociceptive ranges, is still a matter of debate. The present consensus is that pain is expressed in a distributed network made of thalamus, SII, insula, ACC, and, less consistently, SI. Here we argument that there must be an entrance to this network. The common denominator to every functional imaging study is that the subjects can distinguish between noxious and non-noxious stimuli, or between two different intensities of noxious stimuli. This is associated with a consistent activation of the insula-SII cortices while activations in other brain areas may be missing or sub-significant. In other words, the operculo-insular cortex activations are the most robust pain-related activations across studies, whatever the manipulation of the pain components, except the discriminative one. Intra-cerebral recordings also pointed out this piece of cortex as being able to encode for pain intensity. As a last physiological argument, stimulating directly the brain with small intensities standardized electrical shocks elicited pain sensations selectively if the electrode was in the operculo-insular cortex. Human models of disease confirmed that epileptic discharges in the insular cortex can produce ictal pain. Insular epile...
Source: Neuroscience Letters - Category: Neuroscience Source Type: research