Visual scanning of the driving environment is a key component in driving. In conditional automation, the vehicle is usually steered by automation, but drivers may be required to take control of the vehicle in certain circumstances. In these takeover situations (TO), visual exploration of the environment is critical for resuming manual control. This study aimed to compare visual explorations over time during TO preparation and actual TO between experienced and non-experienced drivers. Twenty-five participants completed three simulated drives, each comprising three TO maneuvers. Visual strategies were measured by the percentage of gaze time allocated to areas of interest (AOIs) and further characterised through visual exploration sequences (scanpaths) during TO preparation and actual TO. The results indicated that experienced drivers gazed more at the road area in which the vehicle would be located at the time of effective TO than non-experienced drivers. Similarly, immediately after resuming manual control, experienced drivers gazed more at areas where potential hazards may be present than non-experienced drivers. Three main scanpath classes were identified during TO preparation: anticipation of trajectory control, anticipation of speed control, and environment exploration. During subsequent manual driving, two scanpath classes emerged: speed control and trajectory control. These findings are discussed in terms of differences in visual strategies between non-experienced and experienced drivers, shaped by situational context. Functionally classifying visual exploration sequences provides insight into TO processes and offers a promising link to drivers’ situation awareness and performance.
OBJECTIVE:Respiratory heart rate variability (RespHRV), the variation in heart rate in phase with breathing, is mainly generated by central brainstem mechanisms. Its characteristics in brain-injured patients are poorly understood. The objective of the study was to characterize RespHRV amplitude and phase in brain-injured patients compared to healthy participants. METHODS:We analyzed 55 brain-injured patients and 31 healthy controls. Physiological signals were recorded and processed to extract RespHRV amplitude and phase. Group differences were assessed using Mann-Whitney and Watson-Williams tests. In an additional analysis, 55 patients' RespHRV amplitude and phase were modeled using generalized linear mixed models to evaluate the impact of sedation, ventilation mode, vasoactive and analgesic drugs, and time. RESULTS:Compared to controls, brain-injured patients exhibited a significantly lower RespHRV amplitude (1.04 [0.45, 1.96] vs. 6.21 [4.08, 9.34] bpm; p < 0.001) and an inverted RespHRV phase, with peak heart rate occurring during expiration rather than inspiration. Mixed-effects modeling revealed that machine-triggered ventilation and high level of sedation induced a significant reduction in RespHRV amplitude. CONCLUSIONS:Brain-injured patients demonstrate markedly impaired central generation of RespHRV. SIGNIFICANCE:This profound alteration of RespHRV reflects impaired brainstem control and offers a potential physiological marker of autonomic and neurological recovery.
Vehicle automation progressively shifts the driver’s role from active operator to passive supervisor, requiring behavioural adaptation. Although a timely issue, little is known about the influence of previous manual driving experience and the duration of automation use on those adaptations. Gaze behaviour during a car-following task were investigated under four automation conditions: Non-Automated (NA), Automated Steering (AS), Highly Automated Driving (HAD), and Fully Automated driving (FA). The sequences of visual explorations across the different areas of interest of the driving scene (i.e., scan paths) were analysed over seven weeks of automation use and for both unlicenced and experienced drivers. The findings reveal that automation alters the distribution of scan paths compared to manual driving. Specifically, automation promotes scenery and supervision scan paths at the expense of driving-control ones, which are crucial for monitoring the road and vehicle speed control. This shift became noticeable once the driver completely disengaged from the physical control of the vehicle, this function being supported by automation. Additionally, driving experience significantly influences gaze behaviour for each automation solution. Novice drivers focus more on speed-monitoring scan paths, whereas experienced drivers display more balanced scan paths. No significant changes in scan paths were observed over time, suggesting that gaze strategies are highly context-dependent. Altogether, this study provides a better understanding of the effects of automation on the dynamics of drivers’ gaze behaviour.
OBJECTIVES:To assess US physicians' estimates of the feasibility of preservation procedures (cryopreservation, aldehyde-based fixation) for enabling future revival, their views on clinical interventions to improve preservation outcomes, and their positions on ethical and legal frameworks surrounding these end-of-life options. DESIGN:Cross-sectional survey conducted October 2025. SETTING:Sermo, an online platform for verified US healthcare professionals. PARTICIPANTS:334 physicians comprising 150 primary care physicians (general practice, internal medicine, family medicine) and 184 other specialists. MAIN OUTCOMES AND MEASURES:Estimated probability that preservation retains neurally-encoded information sufficient for future revival; support for pre-mortem anticoagulation and pre-cardiac arrest procedure initiation; views on compatibility with patient-centered care. RESULTS:Among 334 physicians, the median estimated probability that preservation under ideal conditions could retain sufficient neural information for future revival was 25.5%. Overall, 27.9% found preservation somewhat or very plausible for enabling future revival; 47.0% found it somewhat or very implausible. Most physicians (70.7%) supported prescribing anticoagulants to terminal patients to improve preservation quality; 11.7% opposed. For patients choosing preservation in combination with medical assistance in dying, 44.3% supported initiating preservation prior to cardiac arrest; 28.8% opposed. Most (58.1%) agreed preservation could be consistent with compassionate care (20.1% disagreed), and 49.1% reported comfort with patients choosing preservation (30.0% uncomfortable). Familiarity with preservation correlated with higher probability estimates (ρ = 0.26; p < 10-3), while end-of-life discussion frequency correlated with support for pre-cardiac arrest procedures (ρ = 0.18; p = 0.003). CONCLUSIONS:US physicians assigned a median 25.5% probability to preservation retaining neural information under ideal conditions in a manner potentially compatible with future patient revival. The majority support for pre-mortem anticoagulation and plurality support for pre-cardiac arrest initiation indicate that many physicians would consider accommodating patient requests for preservation-enhancing interventions. These findings may inform development of clinical guidelines, though the speculative nature of the estimates warrants consideration.
Objectif Au-delà de son rôle dans la vision, la lumière est le principal synchroniseur de notre horloge circadienne et module de manière aiguë de nombreuses fonctions physiologiques via des mécanismes non visuels. Si son influence sur la vigilance ou la sécrétion de mélatonine est bien établie, son impact sur les systèmes sensoriels comme l’olfaction et sur le métabolisme glucidique reste méconnu. Ces deux systèmes, olfaction et glycémie, présentent une rythmicité circadienne et sont des régulateurs clés du comportement alimentaire. Notre étude a testé l’hypothèse selon laquelle une exposition lumineuse aiguë pourrait moduler directement la sensibilité olfactive et la glycémie chez l’humain. Méthodes Soixante-dix-huit participants en bonne santé (27,1±6,5 ans) ont été inclus dans 2 études contrôlées en laboratoire. Ils ont été exposés à des épisodes de lumière blanche de quatre intensités croissantes (0,5, 10, 100, et 1500 lux) ou bien à 4 spectres différents (obscurité, lumière rouge, bleue, rouge+bleue), de 30min chacune, durant l’après-midi. La sensibilité olfactive a été évaluée à l’aide de deux odorants (alcool phényléthylique et eucalyptol), et la glycémie a été mesurée avant et après chaque exposition lumineuse. Les relations dose-réponse ont été caractérisées à l’aide de régressions sigmoïdales, conformément aux approches psychophysiques standards. Résultats Nos résultats montrent que la lumière augmente de manière significative et intensité-dépendante la sensibilité olfactive, à partir d’un très faible niveau d’éclairement (10 lux). Inversement, l’exposition à la lumière réduit significativement la glycémie, également à partir de 10 lux. Pour ces deux paramètres, les effets sont robustes et parfaitement décrits par une réponse sigmoïdale (R2 proche ou égal à 1), attestant d’une relation forte entre l’intensité lumineuse et la réponse physiologique. Conclusion Cette étude fournit la première preuve chez l’humain qu’une exposition lumineuse aiguë exerce un double effet : elle augmente la sensibilité olfactive tout en diminuant la glycémie. La synergie de ces deux effets suggère l’existence d’une voie non-circadienne par laquelle l’environnement lumineux quotidien pourrait influencer directement les mécanismes de régulation de l’appétit et le comportement alimentaire. Ces effets, potentiellement dépendants du moment de la journée (jour vs nuit), ouvrent des perspectives fondamentales pour comprendre les liens entre environnement, nutrition et santé métabolique.
