The overall objective of the EXOMAN project is to improve the symbiosis between humans and exoskeletons. To do so, we aim to advance fundamental knowledge about Human-Exoskeleton Interaction (HEI) by focusing on the human dimension. The potential use of exoskeletons holds much promise in the fields of ergonomics and healthcare, be it for preventing musculoskeletal disorders or overcoming motor deficits. Regardless of the specific end-goal (e.g. augmentation of an operator’s physical capacity or physical assistance for a patient), active exoskeletons may provide a means to assist the movements of a patient/worker with all the advantages offered by robotics: repeatability, accuracy, adaptability. Following an exponential increase in exoskeleton research over the last decade, several types of robotic exoskeletons have been developed. In particular, upper-limb exoskeletons have generated considerable interest, with many potential applications related to reaching and manipulation of objects in clinical and industrial settings. To date however, the generalization of this technology from research into practical applications (i.e. out of the lab) has been limited. Furthermore, the benefits of these devices over existing techniques (e.g. proactive ergonomics or occupational therapy) have not been scientifically established. Clearly, certain aspects of exoskeleton design are limiting their effectiveness and applicability in real life applications. Beyond the inherent technological challenges (actuators, large weight, energy supply...), a fundamental issue is our limited understanding of human motor control in interaction with an exoskeleton. Our research hypothesis is that breakthroughs in robotic exoskeletons will go hand in hand with a better comprehension of the human contribution to HEI. Quantifying and deciphering how humans adapt to moving while wearing an active upper-limb exoskeleton (and why they do so) will thus be a leading theme of this project. The EXOMAN project will be organized around 4 scientific work packages. Experimental tests will be conducted with ABLE, a highly-reversible upper-limb robotic exoskeleton. Firstly, a technological platform to measure an exhaustive set of human movement parameters (kinematics, dynamics, and energetics) during HEI will be established (work package 1). This will allow conducting exhaustive analyses of human motor behavior in interaction with ABLE (work package 2). Different movement patterns should be observed as a function of the control applied by the exoskeleton and the physical coupling of the person’s upper limb to the exoskeleton. Two complementary research efforts are thus proposed. On the one hand, anthropomorphic high-level control laws for the upper limb exoskeleton will be developed (work package 3). On the other hand, the design of physical interfaces between the person and the exoskeleton will be optimized (work package 4). A standard applied task will be to help/assist an operator to move their limb and a load, from one location to another, in an ecological, comfortable and effortless way. In summary, this interdisciplinary project involving motor control scientists and roboticists will tackle both fundamental and technological issues to boost HEI research and bring active exoskeletons closer to real world applications.

When we engage in daily reward-oriented behaviors such as reaching for a glass of wine or walking to meet some friends, we trade effort against time because immediate rewards are more valuable than delayed ones. Thus, effort and time can be considered as two interdependent costs that must be optimized to maximize the utility of a particular action. Still, how time and effort interact to affect both reward-oriented decisions and movements has not been investigated comprehensively. Moreover, how the effort-time tradeoff varies between individuals and across species is largely unknown. The first objective of our proposal is to investigate and compare how humans, monkeys, and rats trade effort against time in similar foraging tasks allowing comparable and selective manipulations of these two costs. Results will be compared between species through the common framework of optimal foraging theory and the predictions of the marginal value theorem. The aim is to identify general and species-specific principles by which time and effort influence foraging decisions and movements with direct relevance for daily behaviors of humans and animals. The second objective of our proposal is to investigate how the effort-time tradeoff is implemented in the brain. Specifically, the dorsal striatum and downstream regions (internal and external segments of the globus pallidus) have recently been implicated in the control of movement vigor and the speed of decision-making but whether these functions are a consequence of an effort-time tradeoff computed within this sensorimotor basal ganglia circuit has not been investigated. Taking advantage of the multi-level (cellular and circuit) neurophysiological tools available in rats and monkeys, we will investigate whether and how that dorsal striatum and globus pallidus influence the effort-time tradeoff in the context of foraging behaviors. At the network level, we hypothesize that time and effort are integrated along the basal ganglia such that its output nuclei generate a signal proportional to the utility of a given action and modulate neuronal activity in neocortical regions implicated in decision-making and motor control processes. At a more cellular level, we will test the hypothesis that the striatal projection neurons forming the direct and indirect basal ganglia pathways bidirectionally control this utility (output) function and, consequently, the effort-time tradeoff. Altogether, this proposal aims at furthering our understanding of how effort and time impact decision-making and movements, at the computational, behavioral and neuronal levels and across motor repertoires and species. Because several prevalent neurological disorders such as Parkinson's disease or depression are associated with alterations of both the time-effort tradeoff and basal ganglia function, our proposal will directly impact our understanding of these diseases and pave the way to new behavioral and neuronal treatments to alleviate the human and societal costs associated with such disorders.

The present project aims to investigate the links between emotions, cognition and behaviour in terms of performance facilitation, protection, and vulnerability as a function of empathetic emotional contexts. The main hypothesis is that the emotional context’s effect on perceptive, executive, motor performances, as well as social cognition, varies according to (1) temperamental factors (personality traits) and (2) the type of empathic adaptation (pre-reflexive vs reflexive ; virtuous vs prejudicial). The groundbreaking nature of this project stems, on the one hand, from an interdisciplinary exploration of the links between emotion and cognition (differential psychology, psychopathology, cognitive neuropsychology, computer science, human movement sciences), and, on the other hand, from the will to understand emotional regulation and its mechanisms, not only in terms of emotional induction, but on how empathetic adaptation facilitates performance. Our population of interest will be healthy individuals, participants for whom temperamental traits are rarely taken into account in emotional adaptation research (e.g. the 5 factor model). The more traditional approach tends to prioritize the investigation of proximal performance predictors such as motivational states (e.g. self-efficacy precepts). Lastly, the current project will also include patients suffering from mood and/or social cognitive disorders (schizophrenia, bipolar disorders). Attempts will be made to identify the factors which may pre-determine an individual’s disposition to take third party (in this case, a virtual character) performance feedback into account towards future performance modulation. Individual emotional regulation profiles could render vulnerable, protect, or facilitate performance depending on the empathetic emotional context. We aim to determine the sources of inter-individual variability which modulate performance (positively or negatively) when a virtual character is either expressing basic emotions that induce (or not) empathetic pre-reflexive resonance (e.g. joy, anger), or expressing more complex emotions, necessitating a more reflexive treatment of empathetic adaptation (e.g. satisfaction, deception, indifference). The main outcome will be modelling of the relationship between emotion and cognition, namely, which component parts mediate the relationship (e.g. emotional regulation, self-efficacy precepts) and which parts (personality traits) moderate overall effects on performance. The applied consequences of the present project will be turned towards e-learning as well as the cognitive remediation of altered functions when working with patients presenting a dysfunction of the emotion-cognition links. Finally, the project hopes to assist protocol definition with regards to the investigation of links between emotions, cognitions and behaviours; to develop multimodal bodies of knowledge on spontaneous complex emotional expression behaviours; and to generate an adapted experimental platform integrating various existing tools towards the study of the affective interaction between users and virtual characters.