Béchir Jarraya: repairing the brain using neurotechnologies
Béchir Jarraya is a neurosurgeon and neuroscience researcher. As head of the Primate Consciousness and Cognition team within the Cognitive Neuroimaging Unit (Unicog – Univ. Paris-Saclay/Inserm/CEA/CNRS) and a university professor and consultant in neurosurgery at Foch Hospital, he devotes his experimental and clinical research entirely to the brain, with the aim of improving the treatment of its disorders.
Béchir Jarraya was born into a Tunisian family; his father was a doctor with a passion for science. He came top in the national baccalaureate examinations in Tunisia before beginning his medical studies at Claude Bernard University in Lyon, with the intention of becoming both a practising doctor and a laboratory researcher. During his internship, he chose to specialise in neurosurgery, a path that took him to Paris in 1998. He discovered a deep attachment to the human aspect of his profession, striving to maintain a balance in which clinical practice and fundamental research feed into one another. Halfway through his residency, his meeting with Stéphane Palfi, the current head of the neurosurgery department at Henri-Mondor Hospital in Créteil, proved decisive: Béchir Jarraya went on to obtain a Master’s degree (2003), his medical thesis (neurosurgery, 2005) and then a PhD in neuroscience (2006).
Parkinson’s: from preclinical research to the operating theatre
His passion for studying the brain was sparked in his first year of medical school, when he read an article in Newsweek magazine. “It discussed the first clinical trials of neuron transplants to treat patients with Parkinson’s disease. I knew straight away that this was what I wanted to do.” Reading L’Homme neuronal (The Neural Man) by Jean-Pierre Changeux reinforced his commitment to this path. “It was the dawn of a new era: until the early 1990s, neurology had mainly involved making diagnoses; now we were finally beginning to repair the brain.” The experimental medicine lectures in Lyon given by the neurosurgeon Michel Jouvet, a pioneer in the discovery of REM sleep, definitively set his career path.
Whilst working on his PhD in neuroscience, Béchir Jarraya collaborated with the British biotech firm Oxford Biomedica to develop a new gene therapy for Parkinson’s disease, which was preclinical work that resulted in a patent. In 2006, he spent a year as a postdoctoral fellow at Harvard University. On his return, he became an assistant consultant at Henri-Mondor Hospital. “We moved from the laboratory to Parkinson’s patients, in whom we administered our gene therapy. The procedure involved an extremely slow neurosurgical injection of modified viruses deep into the brain, so that the cells would start producing dopamine again. That’s where the translational aspect really came into its own.” The researcher still speaks with emotion about the photo sent by his first patient a few months after the operation, posing proudly, free from his rigidity and tremors.
In 2008, Béchir Jarraya met Stanislas Dehaene, scientific director of NeuroSpin, an international reference laboratory within the CEA specialising in neuroimaging. With funding from the Inserm Avenir programme and the expertise he had acquired at Harvard, he was given free rein to assemble his neuromodulation team. At the same time, he was appointed university professor and hospital practitioner (PU-PH) at the University of Versailles – Saint-Quentin-en-Yvelines (UVSQ).
Understanding and restoring consciousness
As he regularly encountered people who had lost consciousness following head injuries or severe cerebral haemorrhages, Béchir Jarraya made this a central focus of his research. “In the early 2000s, consciousness moved from the realm of philosophy to become a fundamental medical discipline within neuroscience." His work initially focused on the fundamental mechanisms of consciousness: together with his team, he identified the neural networks that generate the phenomenon of consciousness, which is common to all mammals, from humans to primates.
He then explored the loss of consciousness—which is reversible under general anaesthesia—using experimental models developed within the Inserm Avenir team by Lynn Uhrig. “Every year, millions of people experience this, but paradoxically, we still have a very poor understanding of the mechanisms involved. We have observed that, even when using anaesthetics that bind to completely different brain receptors, the clinical outcome remains the same.” This is how the team formalises the concept of the structure-function relationship. “Imagine that our brain is our planet Earth and that functional MRI is a satellite monitoring the road network. We found that, in the conscious state, the road network – comprising motorways and secondary roads – is fluid and flexible. In contrast, under general anaesthesia, the network is restricted to motorways, effectively causing traffic jams. This is how our team discovered a universal brain signature of loss of consciousness under general anaesthesia. Later, this signature proved to be of great interest in patients with disorders of consciousness.”
Finally, Béchir Jarraya is focused on developing tools to reverse this state. By applying the technique of deep brain stimulation via an implant inserted into the centre of the thalamus, his team has demonstrated that targeted stimulation can instantly "wake up" an animal model under deep general anaesthesia, with the animal slipping back into unconsciousness as soon as the current is stopped.
The convergence of neurotechnologies for medical applications
Today, Béchir Jarraya’s research is developing along two converging lines. The first involves modelling ten years of experimental data collected at NeuroSpin using various methods, including artificial intelligence, with the aim of predicting the brain dynamics underpinning states of consciousness. To this end, he draws on the neuro-computational architectures of the European EBRAINS project, working in close collaboration with the University of Cambridge and Alain Destexhe’s team at the Paris-Saclay Institute of Neurosciences (NeuroPSI – Univ. Paris-Saclay/CNRS).
The second strand is translational and directly targets patients in a coma or with chronic disorders of consciousness. “From an ethical standpoint, it is difficult to justify major neurosurgical procedures to implant electrodes in patients who are obviously unable to give their consent. We have certainly tried transcranial direct current stimulation (tDCS), but it only stimulates the superficial cortex and does not reach deeper structures. A genuine revolution that has just begun is the use of focused ultrasound. In collaboration with CEA laboratories, the start-up TheraSonic and the École supérieure de physique et de chimie industrielles de la ville de Paris (ESPCI or Higher School of Industrial Physics and Chemistry of the City of Paris), this technology would enable the same modulation to be achieved in the centre of the brain as an implanted electrode would, but without any incisions whatsoever. This offers immense hope for clinical application in patients suffering from chronic or acute disorders of consciousness." With neuro-computational modelling, it would become possible to predict, guide and evaluate the effects of focused ultrasound brain stimulation.
Béchir Jarraya has received numerous honours throughout his career, including the Émile Delannoy-Robbe Prize from the National Academy of Medicine in 2025. “I appreciate academic recognition, but my greatest source of pride remains the thrill of scientific discovery.” The researcher is also a member of the Parliamentary Office for the Evaluation of Scientific and Technological Choices (OPECST), mindful of the potential pitfalls of transhumanism. “Neurotechnologies represent a magnificent revolution for patients, but a rigorous ethical framework is essential. My role as a clinical researcher is to ensure they are used solely and wisely to help people suffering from neurological conditions or disabilities,” he concludes.
