Publications by Traian Popa | EPFL Graph Search

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

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

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

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

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

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

Native learning ability and not age determines the effects of brain stimulation

Friedhelm Christoph Hummel, Pablo Maceira Elvira, Traian Popa, Anne-Christine Schmid, Andéol Geoffroy Cadic-Melchior

Healthy aging often entails a decline in cognitive and motor functions, affecting independence and quality of life in older adults. Brain stimulation shows potential to enhance these functions, but studies show variable effects. Previous studies have tried ...

2024

Physiology-inspired bifocal fronto-parietal tACS for working memory enhancement

Friedhelm Christoph Hummel, Pablo Maceira Elvira, Sylvain Jean-François Harquel, Traian Popa

Aging populations face significant cognitive challenges, particularly in working memory (WM). Transcranial alternating current stimulation (tACS) offer promising avenues for cognitive enhancement, especially when inspired by brain physiology. This study (N ...

2024

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

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

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

Depotentiation of associative plasticity is intact in Parkinson's disease with mild dyskinesia

Traian Popa

Objective: Depotentiation of homosynaptic plasticity of the primary motor cortex (M1) is impaired in patients with Parkinson's disease (PD) who have developed dyskinesias. In this exploratory study, we tested whether this holds true for heterosynaptic plas ...

ELSEVIER SCI LTD2022

Toward individualized medicine in stroke-The TiMeS project: Protocol of longitudinal, multi-modal, multi-domain study in stroke

Jean-Philippe Thiran, Dimitri Nestor Alice Van De Ville, Olaf Blanke, Silvestro Micera, Friedhelm Christoph Hummel, Gabriel Girard, Takuya Morishita, Elena Beanato, Estelle Emeline Raffin, Sylvain Jean-François Harquel

Despite recent improvements, complete motor recovery occurs in < 15% of stroke patients. To improve the therapeutic outcomes, there is a strong need to tailor treatments to each individual patient. However, there is a lack of knowledge concerning the preci ...

FRONTIERS MEDIA SA2022

Transcranial magnetic stimulation of the brain: What is stimulated? - A consensus and critical position paper

Traian Popa

Transcranial (electro)magnetic stimulation (TMS) is currently the method of choice to non-invasively induce neural activity in the human brain. A single transcranial stimulus induces a time-varying electric field in the brain that may evoke action potentia ...

ELSEVIER IRELAND LTD2022

Inter-Individual Variability in Motor Output Is Driven by Recruitment Gain in the Corticospinal Tract Rather Than Motor Threshold

Traian Popa

Variability in the response of individuals to various non-invasive brain stimulation protocols is a major problem that limits their potential for clinical applications. Baseline motor-evoked potential (MEP) amplitude is the key predictor of an individual's ...

MDPI2022

Dissecting motor skill acquisition: Spatial coordinates take precedence

Friedhelm Christoph Hummel, Takuya Morishita, Pablo Maceira Elvira, Traian Popa, Anne-Christine Schmid, Maximilian Jonas Wessel

Practicing a previously unknown motor sequence often leads to the consolidation of motor chunks, which enable its accurate execution at increasing speeds. Recent imaging studies suggest the function of these structures to be more related to the encoding, s ...

AMER ASSOC ADVANCEMENT SCIENCE2022