Centre Hospitalier Universitaire de Grenoble

Acquisition of synchronized cardiovascular signals from non-invasive measurements (ECG, photoplethysmography pulse sensors, inductance plethysmography) in healthy volunteers aged from 18 to 75, during spontaneous ventilation with apneas (20 seconds) for a total acquisition time of 30 minutes.

Non-traumatic SAH, linked in 85% of cases to the rupture of an intracranial aneurysm, is a serious stroke affecting young people. Half of all survivors suffer cognitive impairment. The presentation is that of a sudden-onset, isolated headache. This population is exposed to headache during hospitalization, which lasts an average of 13 days. This length of hospitalization is due to the fact that these patients must be monitored during the potential vasospasm period that occurs between days 4 and 14 after SAH. The pain associated with SAH is a source of discomfort and increased morphine consumption during the ICU stay, particularly during the first 10 days. Current recommendations call for conventional pain management with a combination of tier 1, 2 and/or 3 analgesics. For headache control, opioids are widely prescribed, sometimes in high doses, with adverse effects, despite efforts to reduce their use. Maximum headache pain scores remain high, indicating inadequate pain management. This highlights the urgent need to study alternative opioid-sparing and analgesia strategies for patients with SAH.

Objectives and research hypothesis Physical inactivity is a major health concern that has been linked to a variety of chronic diseases, including obesity, diabetes, cancer, cardiovascular diseases, and mental disorders. Recent studies have shown that regular physical activity can decrease the risk of SARS-CoV-2 infection, and severe COVID-19 illnesses, as well as improve antibody response to vaccine. As such, the adoption of a physically active lifestyle carries potential health benefits and has even been referred to as a "miracle cure" by the Academy of Royal Medical Colleges. Despite the implementation of policies that aimed to encourage regular physical activity, the prevalence of insufficient physical activity in high-income countries has increased since 2001 (32% in 2001 vs. 37% in 2018). Given the limited impact of health policies on physical activity engagement, it is essential to explore other avenues of research that can contribute to understanding this high level of inactivity and driving innovative strategies for encouraging physical activity. In this context, the automatic attraction of individuals toward activities associated with low-effort exertion is thought to play a key role in physical inactivity. Physical activity involves exerting physical effort, i.e., intensifying physical energy to achieve certain goals, such as increasing the force to lift a heavy object. This physical intensification is associated with the phenomenological experience of energy exertion. Higher effort perception is thought to be aversively valued by inactive individuals, inhibiting their engagement in regular physical activity. However, there is a lack of knowledge regarding the neural correlates of effort perception and how they relate to physical inactivity. It is crucial to gain insights into these neural correlates, especially to enhance our comprehension of the significance of effort minimization in physical inactivity. This project aims to decrease effort perception and improve the valuation of effort, incentivize regular physical activity, and improve overall health outcomes.
Objective 1. Despite ongoing research, there is a lack of agreement on the neural mechanisms underlying effort perception as well as the role of sensorial feedback. Tasks EEG and fMRI aim to address this issue with original experimental methods in order to identify this neural mechanism.
Hypothesis 1. Following A) muscle vibration and B) Induced ischemic paralysis and anesthesia, we expect decreased effort perception associated with a lower cortical S1 activation, unchanged activation in premotor structures, and preserved functional connectivity between premotor regions and S1.
Objective 2. To unravel the neural interaction between efference copy and reafferent muscle spindle signals that contribute to effort perception Hypothesis 2. The neural correlates of effort perception involve interactions between premotor and sensory brain structures. Neural activation patterns of the brain regions implicated in effort perception vary depending on an individual's inclination to engage in physical activity.
Objective 3. Task 3 will examine the potential of non-invasive brain stimulation techniques (TMS) to reduce effort perception in turn increase its perceived value quantified with the CR100 scale, the outcome variable of this study.
Hypothesis 3. Vibration-induced desensitization of muscle spindles and the SMA cTBS reduce effort perception and improve the subjective value of physical effort.