Séminaire COSY: "The posterior insula is not a primary cortex for pain."

Ce séminaire (invitation) se déroulera dans la salle de séminaire Martin V 42B, de 12h30 à 13h30 sur le campus de Louvain-en-Woluwe (UCL) et s'inscrit dans le cadre du cycle de séminaires 2015-2016 organisé par le pôle COSY.

ABSTRACT : A widely accepted textbook notion is that the insula, especially its posterior portion, plays a specific role in the perception of pain. However, this interpretation is largely based on reverse inference, and a specific involvement of the insula for pain has never been demonstrated. In this seminar, I will present recent findings obtained from intracerebral depth electrodes implanted in the human anterior and posterior insula. First, I will show that transient nociceptive and non-nociceptive vibrotactile, auditory, and visual stimuli all elicit consistent local field potentials (LFPs) in both the anterior and posterior insula, with matching spatial distributions. These nociceptive and non-nociceptive LFPs can be largely explained by multimodal neural activity unrelated to pain and nociception. This finding confutes the widespread assumption that LFPs recorded from the human insula are a signature for pain perception and its modulation.Second, I will present data showing that, for both nociceptive and non-nociceptive modalities, stimulus repetition – and therefore the reduction of stimulus salience – has no effect on the intensity of perception, but is associated with a significant decrease of LFP amplitude. This finding suggests that LFPs elicited in the human insula by transient nociceptive and non-nociceptive stimuli reflect multimodal activity involved in detecting, orienting attention towards, and/or reacting to the occurrence of salient sensory events, regardless of the sensory modality through which these events are conveyed, and independently of perceived intensity. Finally, I will show that nociceptive stimuli, but not non-nociceptive stimuli, elicit an early-latency burst of gamma-band oscillations (GBOs) at several insular locations. These high frequency activities could reflect neural processes through which pain actually arises from nociception in the human brain.