SYLVAIN HARQUEL

My research primarily focuses on innovative non-invasive brain stimulation, including robotized TMS, TMS-EEG mapping and closed-loop approaches, to study the healthy and pathological brain. I am particularly interested in understanding the neurophysiological mechanisms underlying stroke motor and cognitive impairment and recovery, with the ultimate goal of designing and optimizing neuromodulation-based rehabilitation therapies. I'm conducting this research as part of the body and space team. I am also co-supervisor of the EEG and TMS platforms at the IRMaGe neuroimaging facility.

Ongoing Projects

CLOSED-LOOP (as PI, CERCOG funding)

This project aims to develop adaptive closed-loop brain state-dependent stimulation protocols. In particular, the goal is to design TMS-EEG closed-loop stimulation that could overcome known limitations, first by incorporating adaptive decision-making modeling to optimize for multiple parameters in parallel (stimulation location, orientation, intensity) while using a wide range of EEG readouts (evoked potentials, frequency-band power, connectivity, etc.), and by integrating state-of-the-art EEG real-time preprocessing to access any cortical target (including frontal, temporal, and occipital lobes).

PhD: S. Varmaghani (co-supervisor); MS: Alexandra Jasaityte (M1 neuropsy. & neurosci. clin.)

TiMeS (PI: Prof. Friedhelm Hummel, EPFL, Geneva)

This research project investigates changes in brain functions that occur after a stroke, and studies how these alterations are related to the recovery of different functions and the daily life of the patients. This is investigated by covering the first year after the initial incident at 4 time points (1st week, 3rd week, 3rd month and 12th month), with the use of multimodal and complementary neuroimaging techniques, including structural and diffusion MRI, resting-state EEG and TMS-EEG. The acquired knowledge will pave the way to develop tailored therapy approaches. These therapy approaches will be based on the individual characteristics of the patient.

ANR VISION-3E (PI: Anna Montagnini, INT, Marseille)

VISION-3E aims to gather behavioral and physiological evidence on the three key functions in the closed-loop processing of human visual perception - expectation, exploration, and exploitation - in order to better understand and model their interaction. The use of closed-loop stimulation approaches in the context of multistable perception will help us to understand the causal role of occipital and fronto-parietal networks in active visual processes involved in the resolution of perceptual rivalry.

PhD: S. Varmaghani (co-supervisor); MS: Kiarash Pedramrad (M2 neurosci. neurobiol.)

MAGTOC (PI: Mircea Polosan, CHUGA)

Deficient motor inhibition is observed in patients with obsessive-compulsive disorder (OCD). Evidence points toward the essential role of two cortical nodes, the pre-SMA and the inferior frontal cortex (IFC), in the brain network supporting response inhibition. This project consisted in a sham-controlled, double-blind and parallel design clinical trial, that aimed at enhancing cortical excitability within the right IFC using intermittent theta-burst stimulation delivered twice a day during two weeks. The stimulation target was individualized to each patient in respect to the maximum activation peak within the right IFC node of the activated motor inhibition network, as observed in fMRI scans during a stop-signal task. As a way to quantify the inhibitory process of the right IFC on the motor cortex, motor excitability was assessed before and after the iTBS cure using dual site TMS.

MS: Cléa Chion (M2R neuropsy. & neurosci. clin.)

NEUROVEC (PI: Michel Guerraz)

Virtual reality systems are more and more frequently used in the field of learning but also in motor rehabilitation. One of the key points of the success of these systems is the experience of "presence" which is associated with the capacity of these technologies to develop in the static observer the sensation of moving in his virtual environment (vection). However, the simulation generates a sensory conflict (an optical flow specifying the movement of the self and vestibular stimuli specifying an immobility of the body). This conflict influences the temporal characteristics of the vection (i.e bistable perception) and consequently modifies the way users act in their virtual environment. The main objectives of our project will be to study the regulation of vection phenomenon through the use of non-invasive brain stimulation, by modulating one of its neural signature: alpha oscillations in sensorimotor and vestibular cortical networks.

Disciplines scientifiques