Regional Brain Stem Atrophy in Idiopathic Parkinson's Disease Detected by Anatomical MRI

Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder characterized by the dysfunction of dopaminergic dependent cortico-basal ganglia loops and diagnosed on the basis of motor symptoms (tremors and/or rigidity and bradykinesia). Post-mortem studies tend to show that the destruction of dopaminergic neurons in the substantia nigra constitutes an intermediate step in a broader neurodegenerative process rather than a unique feature of Parkinson's disease, as a consistent pattern of progression would exist, originating from the medulla oblongata/pontine tegmentum. To date, neuroimaging techniques have been unable to characterize the pre-symptomatic stages of PD. However, if such a regular neurodegenerative pattern were to exist, consistent damages would be found in the brain stem, even at early stages of the disease. We recruited 23 PD patients at Hoenn and Yahr stages I to II of the disease and 18 healthy controls (HC) matched for age. T1-weighted anatomical scans were acquired (MPRAGE, 1 mm3 resolution) and analyzed using an optimized VBM protocol to detect white and grey matter volume reduction without spatial a priori. When the HC group was compared to the PD group, a single cluster exhibited statistical difference (p<0.05 corrected for false detection rate, 4287 mm3) in the brain stem, between the pons and the medulla oblongata. The present study provides in-vivo evidence that brain stem damage may be the first identifiable stage of PD neuropathology, and that the identification of this consistent damage along with other factors could help with earlier diagnosis in the future. This damage could also explain some non-motor symptoms in PD that often precede diagnosis, such as autonomic dysfunction and sleep disorders

Nuclear decommissioning: project management and leadership

Management and leadership for safety relate to managerial competencies necessary to develop, promote and sustain a safety culture and to set goals, lead others and manage knowledge and projects to enhance safety performance. The development of these competencies is needed to enrich and complement the predominant technical background and skills of engineers and/or managers involved in the nuclear sector and particularly in decommissioning and dismantling (D&D) projects. The recent recognition of the importance of managing for safety led the International Atomic Energy Agency (IAEA) to develop formal safety requirements that are now implemented by its member states. This includes the need to develop training and education for beginning- and mid-career managers with nuclear safety responsibilities and, considering the time frame of D&D projects, for future generations of managers. Training and education challenges are acute in all Instrument for Nuclear Safety Cooperation (INSC) and European countries, where managers need to develop knowledge and comprehensive safety-related competencies to run the D&D projects of nuclear facilities in a context where the generational change of managers in the nuclear field is happening fast. In 2016/2017 the IAEA and the European Commission (EC) developed a cooperative framework to jointly address a similar challenge related to operation and regulatory oversight of nuclear installations. The development of these projects was possible by funding from the European Union (EU) through its INSC instrument. The first project, led by the IAEA in 2017, was the development of a pilot school for safety leadership at the University Côte d\u27Azur (UCA), France. Encouraged by this success, the agency has since then developed the syllabus into a 2-week programme, still based on experiential learning, which is offered to IAEA member states who wish to organise sessions for their managers (regulatory bodies or industry). The second project, named ELSE, was operated by UCA and aimed to develop training to help managers acquire leadership for safety capabilities, which are key professional requirements in complex, high-risk and highly regulated sectors such as the nuclear sector. The originality of the ELSE project stemmed from its science-based approach, integrating the most recent findings of management and other social sciences. The dedicated ELSE training programme is composed of a massive online open course (MOOC), a 10 d of face-to-face training and an individually tutored project. Based on the success of these experiences, the EU decided to prolong these actions in the field of nuclear D&D, leading to the start-up, in 2023, of the Decommissioning Management and Leadership for Safety Education (DMaLSE) project. This project has also been entrusted to UCA, in partnership with SKEMA Business School, the Karlsruhe Institute of Technology (KIT) and Jacques Repussard Conseil. DMaLSE has two main objectives, namely to develop a science-based training programme for future D&D project managers and to extend the impact of the project through bachelor-degree-level on-site training for operators involved in D&D projects

Bases neurales de la cognition séquentielle chez l'homme (étude IRMf et MEG)

La facultŽ dÕexŽcuter des sŽquences dÕactions est essentielle lÕhomme, mais lÕimplŽmentation neurale de leur reprŽsentation reste mal comprise. Nous avons crŽŽ un protocole expŽrimental permettant de sŽparer les reprŽsentations ordinales (position relatives des pas de la sŽquence) et hiŽrarchiques (relations entre les segments autonomes des sŽquences) impliquŽes lors de lÕexŽcution des sŽquences. En utilisant lÕIRMf, nous avons mis en ŽvidenceÊ: 1. Un rŽseau frontal bilatŽral hiŽrachique, impliquŽ dans la sŽlection des actes moteurs simples (BA 6), des chunks dO action (ensemble dÕactes moteurs ordonnŽs ou associŽs des stimuli, BA 44) et des chunks superordinŽs (ensemble de chunks ordonnŽs ou associŽs des stimuli, BA 45). 2. Un rŽseau pariŽtal maintenant la composante ordinale des sŽquences (IPS gauche) et le chunk dÕaction moteur courant (IPS droit) associŽ chaque pas. Le protocole expŽrimental a ŽtŽ adaptŽ la MEG afin de dŽterminer la dynamique temporelle de ce rŽseau.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Safety leadership in high risk and highly regulated sectors: A theoretical framework

International audienceThe investigation of major accidents reveals the importance of organizational factors and safety culture in ensuring safety in high-risk environments. Safety research highlights the existence of two types of safety: regulated and managed. While regulated safety focuses on technical/procedural barriers and predictable outcomes, managed safety refers to proactive behavior in face of unpredictable events. Research shows that regulated safety jeopardizes managed safety but there is dearth of research on their articulation and on the role of leaders in this context. Research on leadership has evolved from static leader-centric toward more processual and context-based models, requiring new methods. This paper develops a critical realist approach to studying safety leadership as a collective, dynamic and contingent process. We combine disparate theoretical domains (safety science, organizational and leadership theory) to propose a conceptual framework based on five mechanisms of managed safety: mobilization of a relational eco-system, risk awareness, vigilance towards weak signals, open/flexible thinking and learning. An integrated conceptual framework is operationalized via an illustrative case study developed in the context of a Pilot International School of Leadership for Safety. This conceptual framework allows to integrate dispersed literature and to improve our understanding of the roles of leaders and safety cultur

Deep Leadership: a Critical Realist Approach to Revisit the Role of Leadership in High-Risk Organizations

International audienc

The dynamics of safety risk perception in high reliability organizations

International audienc

The dynamics of safety risk perception in high reliability organizations

International audienc

The dynamics of safety risk perception in high reliability organizations

International audienc

Safety Leadership in Complex High Risk Environments: a theoretical synthesis and integrative framework

International audienc

La sûreté à l’épreuve de la complexité : les limites de l’action managériale

Les « systèmes presque totalement sûrs » se veulent reposer sur une sûreté réglée visant à prévoir tout ce qui est possible, et une sûreté gérée prévue pour faire face à l’imprévu. Mais l’accumulation des règles ou leur mauvaise application peut fragiliser l’édifice. Identifier les limites de l’action managériale est nécessaire pour accroître la fiabilité de ces systèmes et en gérer la sophistication