Research topics - Clinicians

Research projects

Intracerebral EEG recordings to investigate the role of the insula in nociception

Investigators : Giulia Liberati, Susana Ferrao Santos, André Mouraux.

A widely accepted notion is that one particular region of the “pain matrix”, the insula, plays a specific role in the perception of pain, and the activity recorded from this region is often considered as an objective signature of pain perception and its modulation. Taking advantage of the high spatio-temporal resolution of direct intracerebral recordings performed in patients undergoing pre-surgical evaluation of focal intractable epilepsy, we recently provided compelling evidence to the contrary. More specifically, we demonstrated that both nociceptive (laser) and non-nociceptive (vibrotactile, auditory, visual) stimuli perceived as equally intense elicit robust local field potentials (LFPs) in the anterior and posterior insula, with matching spatial distributions. These findings argue against the notion that LFPs recorded from the human insula reflect the brain activity through which pain emerges from nociception in the human brain.
Another finding that emerged from our intracerebral investigations is that nociceptive stimuli, but not tactile, auditory, and visual stimuli, elicit an early-latency burst of gamma-band oscillations (GBOs, 40-90 Hz) at several insular locations. Because perception has been proposed to emerge from temporal binding or synchronization of stimulus-evoked neural activity through GBOs, nociceptive GBOs generated in the insula could reflect cortical activity through which the perception of pain arises from nociceptive input in the human brain.  These pain-related GBOs generated in the insula could also contribute to the generation of higher-order responses aiming at preserving the individual’s integrity.
Whereas insular LFPs appear to reflect multimodal activity unspecific for pain, the selective enhancement of insular GBOs elicited by nociceptive stimuli could reflect activity related to the processing of spinothalamic input, nociception, and/or the perception of pain.

Capsaicin-induced neuroplasticity : mechanistic studies for understanding neuropathic pain and optimizing its treatment

Investigators : Sabien van Neerven, Ronald Deumens, Marjolein Leerink, Patrice Forget, Arnaud Steyaert, André Mouraux, Emmanuel Hermans.

The general objective of our project is to characterize the effects of topical capsaicin treatment on the changes in function and structure of nociceptive pathways associated with the development of chronic neuropathic pain and/or central sensitization. The proposed project is translational, from bench to bedside, as it will combine work performed in an animal model of neuropathic pain and work performed in patients suffering from chronic post-operative pain. Understanding how topical capsaicin may exert an effect on the central mechanisms associated with chronic pain could lead to a better understanding of these mechanisms and their actual involvement in chronic pain, thus opening new perspectives for treatment. Furthermore, it could lead to a better understanding of why some patients respond well to specific treatments such as topical capsaicin, whereas others do not. Finally, it may lead to the identification of specific patient profiles predicting response to treatment (Jensen and Finnerup 2014, Baron 2012). Such knowledge would be of high value for daily medical practice, as it would enable more individualized and effective pain treatment strategies.