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Overview

Our work on perceptual consciousness, metacognition and brain-computer interfaces

We combine psychophysics, computational modeling and invasive electrophysiology to study the mechanisms that lead neurons in our brain to give rise to our perceptual experience of the world and the associated confidence or lack thereof. We are also interested in explaining how this mechanism dysfunctions, leading to hallucinations and doubt in psychiatric and neurological pathologies. This work is supported by an ERC Starting Grant led by Michael Pereira at the Grenoble Institut des Neurosciences in Grenoble, France.

[ 01/02/24 ] New member
Shiva Mahdian just joined our group to search for neural correlates of consciousness that follow the temporal unfolding of our perceptual experience. Welcome!
[ 01/12/23 ] New member
Aziza Chebil just joined our group to study hallucinations in Parkinson's disease. Welcome!
[ 17/11/23 ] New article
Our collaborative review about domain-general metacognition is published in Nature Reviews Psychology
[ 30/08/23 ] New article
Our work on metacognition when detecting visual deviation with Indrit Bègue and others is published in Journal of Neuroscience

The Team

Michael Pereira
Researcher

Michael Pereira

François Stockart
PhD student

François Stockart

Ramla Msheik
PhD student

Ramla Msheik

Childéric Dezier
PhD student

Childéric Dezier

Aziza Chebil
PhD student

Aziza Chebil

Shiva Mahdian
PhD student

Shiva Mahdian

Pauline Laurent
Master's student

Pauline Laurent

Emma Sirouet
Master's student

Emma Sirouet

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Michael Pereira

Michael obtained a Master in Communication Systems at Ecole Polytechnique Fédérale de Lausanne (EPFL). After two years working as engineer at Sony Deutschland GmbH, he obtained a Ph.D. from EPFL with José del R. Millán. He did a first postdoc at EPFL with Olaf Blanke, then joined Nathan Faivre at the Laboratoire de Psychologie et Neurocognition in Grenoble for a second postdoc funded by the Swiss National Science Foundation. He is now a scientist at the National Institute of Health and Medical Research (INSERM) at the Grenoble Institut des Neurosciences (GIN) in Grenoble.
His is interested in studying the mechanisms underlying our conscious experience using single neuron recordings in humans. He is funded by an ERC project, LEAP, that will test a mechanism based on evidence accumulation in the LEAP project
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Nathan Faivre

Nathan obtained his Ph.D. at the Ecole Normale Supérieure in Paris with Sid Kouider. He worked as a postdoc at the California Institute of Technology in Pasadena with Christof Koch, and at the Swiss Federal Institute of Technology in Geneva with Olaf Blanke. After two years at the Centre d’Economie de la Sorbonne in Paris, he is now a CNRS scientist at the Laboratoire de Psychologie & Neurocognition in Grenoble.
Most of his current research is dedicated to metAction, an ERC-funded project which aims to document the contribution of sensorimotor signals to metacognition, and develop new remediation procedures.
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François Stockart

François received his master’s degree in cognitive science from the Université de Paris and Ecole Normale Supérieure (Cogmaster), under the supervision of Claire Sergent. There, he worked on the influence of unconscious stimuli on eye movements and investigated the neural correlates of retrospective attention using magnetoencephalography.

In his Ph.D. co-supervised by Nathan Faivre and Michael Pereira, he will be investigating the neural mechanism of consciousness by testing the predictions of an evidence accumulation model that purports to explain conscious perception. He will be using electroencephalography (EEG) and intracranial EEG (iEEG).
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Pauline Laurent

After a Bachelor's degree in Psychology at Université Savoie Mont Blanc, Pauline is finishing her Master's in Neuropsychology and Clinical Neurosciences at Université Grenoble-Alpes. She joined our group for her Master's thesis which will consist of searching for behavioral and EEG markers of obsessive-compulsive symptoms with Childéric Dezier.
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Ramla Msheik

Ramla got a Bachelor degree in Physics at the Lebanese University of Beirut. Then she came to France to pursue her studies and obtained a Master degree in Philosophy at Grenoble Alpes University.

Her PhD project co-supervised by Nathan Faivre and Michael Pereira consists in adjusting a computational model to a set of behavioral and electroencephalography data. This approach would allow us to test the role of latent evidence accumulation processes for perceptual experience. She will also apply this model to characterize metacognitive deficits in schizophrenia.
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Childéric Dezier

Childéric received his master's degree in cognitive science from Grenoble INP. During his studies, he undertook an internship characterizing metamemory and metaperception in schizophrenia spectrum disorders under the guidance of Nathan Faivre about
Childéric joined our team as a Ph.D. candidate at the Grenoble Institute of Neuroscience (GIN), co-supervised by Mircea Polosan and Michael Pereira. He will delve into the intricacies of Obsessive-Compulsive Disorder (OCD), with a specific focus on identifying both electrophysiological and behavioral biomarkers of the disorder. His thesis not only aims to enhance the understanding of OCD through a detailed study of decision-making processes and metacognition but especially to pave the way for innovative therapeutic approaches, with a focus on closed-loop techniques such as neurofeedback.

He is funded by the Grenoble Neurotech CDP.

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Emma Sirouet

Emma did her Bachelor's degree in Psychology at Université Bordeaux. She is now pursuing a Master's degree in Neuropsychology and Clinical Neurosciences at Université Grenoble-Alpes. She joined our group for an internship during which she will test behavioral manipulations to modulate the proportion of false-alarms in a visual detection task with Ramla Msheik.
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Aziza Chebil

Aziza did a bachelor's in life science at Université Paris Descartes with a one-year exchange at Université du Quebec à Montréal during which she studied mathematics and philosophy. She then obtained a Master degree from Sorbonne University in Integrative Biology and Physiology with a focus on modelling and data analysis.

In her PhD, she studies false perceptions such as hallucinations using psychophysical methods in healthy participants and patients with Parkinson's disease with visual hallucinations. She applies computational models of evidence accumulation to understand the underlying mechanisms better.

She is funded by the LEAP project.

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Shiva Mahdian

Shiva obtained her master’s degree in Neuroscience engineering from PSL, and Université de Paris. She engaged in fundamental and applied research, contributing to the development of a passive brain-computer interface for stress detection at Mind & Act, Capgmeni and conducting in vivo signal analysis to characterize the encoding of movement kinematics at the University of Oxford.

In her Ph.D, co-supervised by Nathan Faivre and Michael Pereira, she investigates the neural mechanism of perceptual onsciousness in particular how the temporal evolution of conscious experience correlates with the activity of single neurons and local field potentials.

She is funded by the LEAP project.


Ajax

Projects

Perceptual consciousness and hallucinations

We test if evidence accumulation explains how our conscious experience unfolds over time and leads to hallucinations in Parkinson's disease.

Condidence or doubt

We are also intersted in understanding the mechanisms underlying the monitoring of our cognitive states which lead to confidence or doubt, especially in obsessive-compulsive disease.

Neurotech

We also like to apply engineering tools to decode brain signals and stimulate with the long-term goal of providing therapies for neurological and psychiatric diseases.

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Perceptual consciousness and hallucinations

How we consciously experience the world remains a mystery in science. To tackle this problem, scientific works on perceptual consciousness contrast brain activity when participants consciously perceive a stimulus versus when they are unaware of it. To report stimulus awareness, participants need to make decisions. However, the extent to which the well-studied mechanisms of decision-making apply to consciousness is unclear. One possible reason is that standard neuroimaging methods lack the sensitivity to observe whether the mechanisms of decision-making also operate in the absence of task-relevance, as when participants become conscious of a stimulus irrespective of any task.

In this project, we will test the hypothesis that a mechanism of decision-making –evidence accumulation– explains how perceptual consciousness unfolds over time. First, we will develop a computational model of a latent evidence accumulation process (LEAP) and test it on behavioral measures of phenomenal aspects of perceptual experience: its duration and intensity. Second, we will search for single neuron activity in humans that instantiates evidence accumulation and test whether it also determines these phenomenal aspects of perceptual experience. Third, we will stimulate the corresponding brain regions to disentangle their causal role in either solely triggering perceptual experience or shaping it. Last, we will use the LEAP model to explain hallucinatory-like experiences in patients with Parkinson's disease and test whether deep-brain stimulation affects only decision-making –as previously shown– or also perceptual experience.

By combining computational modeling and cutting-edge electrophysiology, the LEAP project will provide unique mechanistic insights on how neuronal activity determines perceptual experience and guides its temporal dynamics. It will also provide a tool to better understand hallucinations, which remain today a major debilitating symptom in numerous psychiatric disorders.

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Condidence or doubt

Upon making decisions, one usually "feels" that a given choice was correct or not, which allows deciding whether to commit to the choice, to seek more evidence under uncertainty, or to change one’s mind and go for another option. This crucial aspect of decision making relies on the capacity to monitor and report one’s own mental states, which is commonly referred to as metacognitive monitoring. Similarly for conscious perception, we can be sure to see a cat, or doubt whether it is a cat or a rock, for example at dusk.

We know that sensory evidence is accrued over time until a bound that leads to a perceptual choice. However, it is still unclear how confidence or doubt arises from this evidence accumulation process and where this is implemented in the brain. Does evidence accumulation continue after the decision? How are prior beliefs about the stimulus integrated?

To study metacognitive monitoring, we develop computational models of confidence based on evidence accumulation. We also record scalp EEG and intracranial EEG from deep-brain stimulation electrode in patients with obsessive-compulsive disorder. Our goal is to better understand the mechanisms of confidence in neurotypical human participants and how they might differ in psychiatric conditions.

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Neurotech

On the side, we are interested in the development of neuro-technologies. We develop new algorithms to decode brain states from electrophysiological activity, sometimes post-hoc, somethimes in real-time. In the later case, we use the output of the decoders to adapt the task, or to adjust the stimulation. This closed-loop technology can be harnessed to induce lasting changes in brain activity, either by adapting the task, or by stimulating the brain at the best moment. Our long-term goal is to develop neuro-technologies to reduce hallucinations and obsessive-compulsive symptoms.

Contact


Grenoble Institut des Neurosciences
Bâtiment Edmond J. Safra
Site Santé
38706 La Tronche Cedex
France
+41 79 409 97 46
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