Publications de Pierre Theopistos Vassiliadis

Reward signals in the motor cortex: from biology to neurotechnology

Solaiman Shokur, Pierre Theopistos Vassiliadis

Over the past decade, research has shown that the primary motor cortex (M1), the brain's main output for movement, also responds to rewards. These reward signals may shape motor output in its final stages, influencing movement invigoration and motor learni ...

NATURE PORTFOLIO2025

Effect of Extrinsic Reward on Motor Plasticity during Skill Learning

Friedhelm Christoph Hummel, Pierre Theopistos Vassiliadis

Human motor skill acquisition is improved by performance feedback, and coupling such feedback with extrinsic reward (such as money) can enhance skill learning. However, the neurophysiology underlying such behavioral effect is unclear. To bridge this gap, w ...

2025

Noninvasive modulation of the hippocampal-entorhinal complex during spatial navigation in humans

Olaf Blanke, Elena Beanato, Hyukjun Moon, Esra Neufeld, Friedhelm Christoph Hummel, Maximilian Jonas Wessel, Baptiste Gauthier, Traian Popa, Pierre Theopistos Vassiliadis, Emanuela De Falco, Pauline Menoud, Fabienne Windel

Because of the depth of the hippocampal-entorhinal complex (HC-EC) in the brain, understanding of its role in spatial navigation via neuromodulation was limited in humans. Here, we aimed to better elucidate this relationship in healthy volunteers, using tr ...

American Association for the Advancement of Science (AAAS)2024

Accelerometry as a tool for measuring the effects of transcranial magnetic stimulation

Pierre Theopistos Vassiliadis, Julie Duqué

Objective: We predicted that accelerometry would be a viable alternative to electromyography (EMG) for assessing fundamental Transcranial Magnetic Stimulation (TMS) measurements (e.g. Resting Motor Threshold (RMT), recruitment curves, latencies). New Metho ...

Elsevier2024

Non-invasive stimulation of the human striatum disrupts reinforcement learning of motor skills

Elena Beanato, Esra Neufeld, Friedhelm Christoph Hummel, Takuya Morishita, Maximilian Jonas Wessel, Traian Popa, Pierre Theopistos Vassiliadis, Julie Duqué, Fabienne Windel

Reinforcement feedback can improve motor learning, but the underlying brain mechanisms remain underexplored. In particular, the causal contribution of specific patterns of oscillatory activity within the human striatum is unknown. To address this question, ...

Nature Portfolio2024

Safety, tolerability and blinding efficiency of non-invasive deep transcranial temporal interference stimulation: first experience from more than 250 sessions

Elena Beanato, Friedhelm Christoph Hummel, Maximilian Jonas Wessel, Pierre Theopistos Vassiliadis, Fabienne Windel, Emma Marie D Stiennon

Objective. Selective neuromodulation of deep brain regions has for a long time only been possible through invasive approaches, because of the steep depth-focality trade-off of conventional non-invasive brain stimulation (NIBS) techniques. Approach. An appr ...

Iop Publishing Ltd2024

Connecting the dots: harnessing dual-site transcranial magnetic stimulation to quantify the causal influence of medial frontal areas on the motor cortex

Pierre Theopistos Vassiliadis

Dual-site transcranial magnetic stimulation has been widely employed to investigate the influence of cortical structures on the primary motor cortex. Here, we leveraged this technique to probe the causal influence of two key areas of the medial frontal cor ...

Oxford Univ Press Inc2023

Mechanisms underlying reinforcement learning of motor skills

Pierre Theopistos Vassiliadis

Motor learning allows animals, including human beings, to acquire skills that are es-sential for efficient interactions with the environment. This ability to learn new motor skills is of great practical relevance for daily-life activities (such as when lea ...

EPFL2023

Noninvasive theta-burst stimulation of the human striatum enhances striatal activity and motor skill learning

Elena Beanato, Pablo Maceira Elvira, Esra Neufeld, Friedhelm Christoph Hummel, Takuya Morishita, Maximilian Jonas Wessel, Chang-Hyun Park, Traian Popa, Pierre Theopistos Vassiliadis, Pauline Menoud, Fabienne Windel

The stimulation of deep brain structures has thus far only been possible with invasive methods. Transcranial electrical temporal interference stimulation (tTIS) is a novel, noninvasive technology that might overcome this limitation. The initial proof-of-co ...

Nature Portfolio2023

Reward timing matters in motor learning

Pierre Theopistos Vassiliadis, Julie Duqué

Reward timing, that is, the delay after which reward is delivered following an action is known to strongly influence reinforcement learning. Here, we asked if reward timing could also modulate how people learn and consolidate new motor skills. In 60 health ...

CELL PRESS2022

An automatized method to determine latencies of motor-evoked potentials under physiological and pathophysiological conditions

Claudia Bigoni, Friedhelm Christoph Hummel, Takuya Morishita, Andéol Geoffroy Cadic-Melchior, Pierre Theopistos Vassiliadis

Background. Latencies of motor evoked potentials (MEPs) can provide insights into the motor neuronal pathways activated by transcranial magnetic stimulation. Notwithstanding its clinical relevance, accurate, unbiased methods to automatize latency detection ...

IOP Publishing Ltd2022

Reward boosts reinforcement-based motor learning

Friedhelm Christoph Hummel, Pierre Theopistos Vassiliadis, Julie Duqué

Besides relying heavily on sensory and reinforcement feedback, motor skill learning may also depend on the level of motivation experienced during training. Yet, how motivation by reward modulates motor learning remains unclear. In 90 healthy subjects, we i ...

2021

Motor training strengthens corticospinal suppression during movement preparation

Pierre Theopistos Vassiliadis, Julie Duqué

Vassiliadis P, Derosiere G, Grandjean J, Duque J. Motor training strengthens corticospinal suppression during movement preparation. J Neurophysiol 124: 1656-1666, 2020. First published September 30, 2020; doi:10.1152/jn.00378.2020.-Training can improve mot ...

AMER PHYSIOLOGICAL SOC2020

Selecting and Executing Actions for Rewards

Pierre Theopistos Vassiliadis

2020