The somatosensory system is responsible for perceiving and analysing inputs such as pain, temperature, and tactile information, among others, and is therefore crucial to the normal functioning of our bodies. To date, different somatosensory modalities have mostly been investigated in isolation. However, in everyday life, we deal with a continuous stream of multimodal sensory information. In this context, studying cross-modal interactions within the somatosensory system is of great scientific interest. My PhD aims to characterise the integration of somatosensory modalities by the central nervous system and the resulting unified perceptions, with a particular focus on grip and haptic exploration. The knowledge gained from this project can then be useful for designing tactile displays and virtual reality setups.

Fibromyalgia is a chronic pain syndrome characterized by diffuse pain and often associated with sleep, mood and cognitive disorders. Patients’ difficulties in managing cognitive effort and distractibility during daily cognitive activities are recognized as cognitive markers of fibromyalgia. These difficulties could be explained either by the fact that their physical symptoms capture their cognitive resources, or by cognitive biases that motivate them to give priority attention to their bodily sensations to the detriment of other information from their environment. However, no study has yet managed to clearly define the cognitive dysfunctions underlying their difficulties. One of the issues raised is that these previous studies have used tools that are poorly suited to assess cognitive function of chronic pain people and with stimuli that are not very relevant to them, such as neutral visual stimuli. The objective of the project is to test in patients with fibromyalgia their abilities to perceive their body and its peripersonal space, as well as their abilities to pay attention and to memorize somatosensory stimuli directly applied to their body (particularly during conflict with non-somatic stimuli).

Localizing pain is an important function as it allows detecting which part of the body is being hurt. It also helps to identify in the space around the body which stimulus is producing the damage. Behavioral studies suggest that the brain has the ability to map nociceptive stimuli according to different spatial representations. The somatotopic representation constitutes an anatomical map of the body surface based on point-by-point correspondences of particular areas of the body to specific groups of neurons in the brain. The spatiotopic representation considers the relative position and movement of the body part on which the stimulus is applied, and, therefore, uses external space as reference frame. The aim of the present research project is to characterize in humans the time course of the neural processes underlying the spatial mapping of nociceptive inputs using electroencephalography. In order to test the influence of early sensory experience in the development of spatial mapping abilities, data of normally sighted participants will be contrasted with those of congenitally blind people.

Physical exercise is increasingly recognized as an effective treatment to reduce pain and improve function in a variety of pain conditions. Studies in humans and non-human animals have shown that a single session of physical exercise can reduce pain perception to experimental stimuli. The mechanisms underlying this exercise-induced hypoalgesia (EIH) remain elusive. Central and peripheral processes have been proposed, but their relative contributions remain unknown. Among others, the sympatho-adrenergic system could be involved in another well-known phenomenon, stress-induced analgesia (SIA). This project aims (1) to shed light on the processes underlying EIH in humans, (2) to explore whether EIH and SIA may share some similar processes, and (3) to test the possible involvement of peripheral α2-adrenergic receptors (α2-AR) in EIH and SIA, and kynurenic acid (KynA, a circulating myokine that transiently increases following exercise) in EIH. First, we will characterize the effects of a single session of aerobic exercise on the sensitivity to stimuli activating skin versus muscle nociceptors, within or outside exercising body parts. We will also evaluate whether exercise modulates secondary hyperalgesia due to central sensitization. Then, we will test whether α2-AR activation contributes to EIH and/or SIA by evaluating the effects of an α2-AR antagonist (single oral dose of yohimbine) compared to placebo. Finally, we will evaluate the contribution of KynA to EIH by relating, across participants and over time, the post-exercise reduction in experimentally induced pain with the post-exercise plasmatic increase of KynA. 

The aim of my research project is to study the mechanisms by which psychological factors can modify spinal activity induced by nociceptive stimuli. It is indeed acknowledged that dysregulation of the pain descending modulatory system as well as sensitization of spinal excitability could be involved in the development of chronic pain. More particularly the objective of my project is to study the impact of hypnotic analgesia on somatosensory-induced spinal activity. Two hypnotic suggestion techniques will be used, a first one aiming to suggest a global analgesia of the body, a second one having the capacity to focus analgesia on a restricted part of the body. Neurophysiological makers of the spinal activity will be the N13 component of the somatosensory evoked potentials, indexing ascending transmission of somatosensory inputs, and the RIII component of the nociceptive withdrawal reflexes, indexing local circuitry and motor response of the spinal activity.

The main goal of my PhD is to investigate the risk factors of chronicity in the chronic regional pain syndrom (CRPS) and in the futur, be able to have an impact on its secondary prevention. We already know some risk factors of onset of CRPS but what's about the chronicity? Through an observational longitudinal study at CUSL, we would like to study some risks factors and then, as in the low back pain, be able to determine which patients are at higher risk of chronicity and which therapeutic interventions to suggest.

Painful stimuli do not only evoke event-related potentials in the brain but also modulate ongoing neural oscillations. Yet, the functional implications of these modulations remains unclear. The main goal of my PhD is to better characterize pain-related modulations of ongoing neural oscillations and to investigate their functional significance. Hereby, the primary focus lies on the dynamic nature of internal and external factors modulating ongoing neural oscillations recorded from scalp and intracerebral EEG and how they can be analyzed using frequency-tagging of ongoing oscillations (FT-OO). A better comprehension of ongoing oscillation will not only deepen the understanding of the neural mechanisms of pain perception but could also be of use in the development of novel long-term interventions in chronic pain conditions.

I pursued studies in biomedical sciences, culminating in a master's degree in neuroscience. Complementing this, I delved into a psychology bachelor, driven by an enduring curiosity to unravel the intricacies of the human brain. My thesis project is dedicated to investigating the neural foundations of thermoception and social cognition, with a specific emphasis on exploring their interconnections and understanding how alterations manifest in the context of frontotemporal dementia. My ultimate goal is to contribute a deeper understanding of these processes, shedding light on the intricate neural dynamics underlying cognitive changes in frontotemporal dementia.

Hypnosis is used to treat a wide variety of diseases and symptoms. It is used, for example, as an anesthetic technique to relieve pain. However, the psychological and neurobiological mechanisms underlying hypnotic analgesia are still poorly understood. My project aims to show, using psychophysics and neurophysiology, that hypnotic analgesia relies on the cognitive ability to control the flow of sensory information in the brain, by selectively modifying the responses to pain stimuli applied on the part of the body on which the hypnosis is focused, which could in turn prevent pain from sensitizing the central nervous system (a mechanism by which the brain amplifies its responses to sensory stimuli, and supposed to be involved in chronic pain).

The objective of my PhD is to evaluate whether pre-operative composition of the intestinal microbiota and/or post-operative changes in microbiota composition influence the intensity of acute PSP and the risk to develop persistent PSP in patients undergoing non-abdominal surgery. Specifically, we hypothesize that composition of the intestinal microbiota could be an important factor influencing the susceptibility to develop peripheral and/or central sensitization and, hence, that pre-operative composition of the intestinal microbiota and/or post-operative changes in its composition could be an important determinant of the severity of acute PSP and the risk to develop persistent PSP.

I joined the group for my PhD within the framework of the MSCA-ITN H2020 project called MULTITOUCH. The broad objective of my PhD is to study how the human brain integrates the multisensory information while actively touching a haptic interface. More specifically, I will investigate if the tactile motion signals generated from active touch are decoded by somatotopic coordinates or an external (visual) frame of reference. So, EEG and fMRI experiments will be conducted to explore the integration of visual and tactile motion signals in healthy as well as blind individuals. A further attempt will be made to build a model that optimally integrates the sensory signals in conditions of active touch.

Touch is a dynamic process: when we explore a surface, sensory input is generated by a number of different sources, including both somatosensory and proprioceptive inputs. My PhD is part of the EU H2020-ITN ‘’MULTITOUCH’’. The aim of my project will be to investigate how stimuli from different sensory modalities (vision, audition) are integrated with tactile feedback under conditions of active, dynamic touch. In order to investigate the neural underpinnings of multisensory integration during haptic exploration, we will use a combination of psychophysical and electroencephalography (EEG) experiments. In collaboration with the other MULTITOUCH partner institutions, this knowledge will be then applied to inform the development of next-generation human-computer interfaces (HCIs), such as multisensory tactile displays, and multisensory virtual reality setups.

The aims of my research project are (1) to evaluate whether olfactory impairment is a reliable predictor of perioperative morbidity and mortality and (2) to identify the potential underlying mechanisms, notably through the links between olfaction, cognition and brain plasticity using olfactory training.

Within the H2020 QSPainRelief project, we will conduct a clinical study in patients suffering from disabling post-operative to assess the different effects of combinatorial treatments on the central nervous system using EEG and other non-invasive electrophysiological techniques and relate these effects to real-life clinical efficacy and safety. The data generated by this clinical study will be used to calibrate a model to predict response to combinatorial treatments for pain.

Within the H2020 QSPainRelief project, we will conduct a clinical study in patients suffering from disabling post-operative to assess the different effects of combinatorial treatments on the central nervous system using EEG and other non-invasive electrophysiological techniques and relate these effects to real-life clinical efficacy and safety. The data generated by this clinical study will be used to calibrate a model to predict response to combinatorial treatments for pain.

Sensitization is a process that consists in amplifying the response to pain consecutive to the repetition of the noxious stimulation. Sensitization is thought to play a role in the development of chronic pain. On the other side, psychological factors are known to modulate the experience of pain and are also suggested to play a role in the development and the maintenance of chronic pain. It is therefore hypothesized that cognitive factors such as attention could influence the risk of chronic pain by modulating the strength and the extent of sensitization. My project aims at observing in healthy volunteers the impact of attention on a lab model of sensitization of the central nervous system consecutive to repeated experimentally-induced painful electrical stimuli.

My PhD is conducted in the framework of a large-scale Innovative Medicines Initiative (IMI PAIN-CARE; https://www.imi-paincare.eu) project, subtopic BioPain. The aim of this subtopic is to identify and validate a number of functional biomarkers based on non-invasive measures of neural activity (peripheral measures of nerve excitability, spinal and brainstem reflexes, measures of brain activity using electroencephalography [EEG] and functional magnetic resonance imaging [MRI] that can be used in humans to assess the effects of a given drug on the nociceptive system. If successful, these biomarkers would be used in future studies for the early stages of the pharmacological development of novel treatments for pain, and back-translated to animal models.

Anaesthesiologist
Dept. of Anaesthesiology - Cliniques universitaires Saint-Luc
PhD student - Supervisor: André Mouraux
FRC
Promoter : Prof. A. Mouraux

Control of acute as well as prevention of chronic postoperative pain remains a challenge. In human volunteers, both transcranial direct current stimulation (tDCS) and transcutaneous spinal direct current stimulation (tsDCS) alter pain perception and its modulation. tDCS may also reduce opioid consumption and pain scores after surgery. As tDCS and tsDCS affect pain processing at different levels, their combined application could produce additive or synergistic effects. The objective of my PhD is to characterize the effects of combined tDCS and tsDCS on acute pain perception and processing (temporal summation, conditioned pain modulation, experimentally induced central sensitization) in healthy volunteers.