Florian Chouchou

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Verified

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• PhD
• Professor (Assistant) at University of Reunion Island

Objective: To assess the value of combining brain and autonomic measures to discriminate the subjective perception of pain from other sensory-cognitive activations. Methods: 20 healthy individuals received 2 types of tonic painful stimulation delivered to the hand: electrical stimuli and immersion in 10 Celsius degree (°C) water, which were contra...

The autonomic nervous system (ANS) harmoniously regulates all internal organic functions (heart rate, blood pressure, vasomotion, digestive tract motility, endocrinal secretions) and adapts them to the needs. It's the control of so-called vegetative functions, which allows homeostasis but also allostasis of our body. ANS is divided into two systems...

Some of the most important integrative control centers for the autonomic nervous system are located in the brainstem and the hypothalamus. However, growing recent neuroimaging evidence support that a set of cortical regions, named the central autonomic network (CAN), is involved in autonomic control and seems to play a major role in continuous auto...

Despite numerous studies suggesting the role of insular cortex in the control of autonomic activity, the exact location of cardiac motor regions remains controversial. We provide here a functional mapping of autonomic cardiac responses to intracortical stimulations of the human insula. The cardiac effects of 100 insular electrical stimulations into...

OBJECTIVE Due to limited information from scalp electroencephalographic (EEG) recordings, brain areas driving changes in cardiac rhythm during Temporal lobe (TL) seizures are not clearly identified. Using stereotactic EEG (SEEG) recordings, we aimed at identifying which of the brain regions involved in autonomic control trigger ictal tachycardia....

Background Post-exertional malaise (PEM) is a complex phenomenon characterized by extreme fatigue, reduced endurance, and muscular and joint pains. Physical activity (PA) has recognized health benefits, including reducing the risks of chronic diseases and mortality. During the pandemic, a general decline in PA was measured, but the profile of the v...

Purpose While motor unit recruitment may be impaired for some clinical populations, and while all-out testing procedures involve repeated maximal contractions to accurately estimate critical torque (CT), no previous study has precisely examined the relationships between voluntary activation percentage (VA%) and difference in CT estimation according...

The global fight against pandemics is a major public health issue. Epidemiological studies showed a reduced risk of the coronavirus disease 2019 (COVID-19) severity with the practice of regular physical activity (PA) in clinical populations. Here, we investigated the effect of PA against COVID-19 in a young general population. Methods: Two hundred...

Objectif - Les objectifs de cette étude pilote sont d'évaluer les effets : 1) de l'activité aérobie intense tardive et 2) de la température sur la latence d'endormissement et la durée des stades de sommeil chez des sujets sains. Méthodes - Après avoir réalisé une épreuve d'effort maximale sur ergocycle, 8 sujets sains actifs ont été soumis à deux...

Homeostatic regulation plays a fundamental role in maintenance of multicellular life. At different scales and in different biological systems, this principle allows a better understanding of biological organization. Consequently, a growing interest in studying cause-effect relations between physiological systems has emerged, such as in the fields o...

Purpose. While motor unit recruitment may be impaired for some clinical populations, and while allout testing procedures involve repeated maximal contractions to accurately estimate critical torque (CT), no previous study has precisely examined the relationships between voluntary activation (VA) and difference in CT estimation according to gold-sta...

Insomnia treatment among individuals with comorbid insomnia and obstructive sleep apnea is suboptimal. In a pilot randomized controlled trial, 19 individuals with comorbid insomnia and obstructive sleep apnea were allocated to one of two arms: EX + EX, consisting of two 8-week phases of exercise training (EX), or RE + CBTiEX, encompassing 8 weeks o...

Introduction: Simultaneous beat-to-beat R-R intervals, blood pressure and respiration signals are routinely analyzed for the evaluation of autonomic cardiovascular and cardiorespiratory regulations for research or clinical purposes. The more recognized analyses are i) heart rate variability and cardiac coherence, which provides an evaluation of aut...

Recent evidence suggests that the autonomic nervous system can contribute to memory consolidation during sleep. Whether fluctuations in cardiac autonomic activity during sleep following physical exercise contribute to the process of memory consolidation has not been studied. We assessed the effects of a non‐rapid eye movement (NREM) nap following a...

Recent evidence suggests that the autonomic nervous system can contribute to memory consolidation during sleep. Whether fluctuations in cardiac autonomic activity during sleep following physical exercise contribute to the process of memory consolidation has not been studied. We assessed the effects of a non-rapid eye movement (NREM) nap following a...

Rationale: Among individuals with obstructive sleep apnea, about 38% will present with comorbid chronic insomnia. Comorbid chronic insomnia and obstructive sleep apnea (COMISA) is associated with poorer daytime functioning and increased morbidity compared to either disorder alone. The treatment of insomnia among individuals with COMISA is suboptima...

When exposed to a viral infection, the attacked cells promptly set up defense mechanisms. As part of the antiviral responses, the innate immune interferon pathway and associated interferon-stimulated genes notably allow the production of proteins bearing antiviral activity. Numerous viruses are able to evade the interferon response, highlighting th...

When exposed to a viral infection, the attacked cells promptly set up defence mechanisms. Part of antiviral responses, the innate immune interferon pathway and associated interferon stimulated genes are notably allowing the production of proteins bearing an antiviral activity. Numerous viruses are able to evade the interferon response, highlighting...

Objective: fibromyalgia is a complex chronic pain syndrome characterized by widespread musculoskeletal pain, insomnia and autonomic alterations. Cognitive-behavioral therapy (CBT) is regarded as a promising treatment in fibromyalgia, but its impact on autonomic function remains uncertain. In this research, we studied the effect of CBT on autonomic...

Background: Insomnia has been associated with decreased academic performance and unhealthy behaviors in university students. Although many studies have analyzed sleep phenomenology among this population, only few have focused on insomnia and its related variables. In addition, such studies do not always include a clinical interview or a specific a...

Background: Cardiac vagal dysfunction was documented in middle-aged patients with migraine. However, vagal activity depends on several psychophysical or physiological factors such as anxiety, depression, lifestyle or age. In this work, we studied cardiac parasympathetic activity in elderly volunteers with past or current migraine. Methods: Among PR...

Mathematical tools applied on physiological parameter have shown their ability to help in our understanding in physiological processes such as autonomic regulations. However, such methods are not adapted to quantify close-loop interactions between respiratory, blood pressure and heart rhythm. To overcome this limitation, classical Granger causality...

Baroreflex sensitivity (BRS) is known to be a predictor of morbidity and mortality in metabolic and cardiovascular diseases. However, although we know that BRS decreases with age, we do not know whether BRS is predictive of mortality in general elderly population. The objective of this work is to study the predictive value of BRS in the mortality o...

Although it is now widely accepted that the brain contributes to the autonomic regulation, the cortical autonomic network is not clearly identified. Here, we provide a functional mapping of cardiac responses to brain stimulations. Methods: The cardiac effects of 1504 intracortical stimulations were divided into tachycardia, bradycardia, and no card...

Objectif Les troubles du sommeil tels que l’insomnie ou le SAOS sont un enjeu de santé public. L’exercice physique est une intervention non médicamenteuse dans les pathologies chroniques qui a montré des effets positifs. L’objectif de l’étude est d’analyser les effets d’un exercice intensif sur le sommeil et l’activité du système nerveux autonome (...

To understand the variable response to pain, researchers have examined the change in cardiovascular measures to a uniform painful stimulation. Pain catastrophizing is the tendency to magnify or exaggerate pain sensations, and it affects the outcome of rehabilitation in a clinical setting. Its effect on cardiovascular changes during a painful stimul...

Background Heart rate variability biofeedback (HRVB) is a non-pharmacological intervention used in the management of chronic diseases. Method A systematic search was performed according to eligibility criteria including adult chronic patients, HRVB as main treatment with or without control conditions, and psychophysiological outcomes as dependent...

Objective Suppression of alpha and enhancement of gamma electroencephalographic (EEG) power have both been suggested as objective indicators of cortical pain processing. While gamma activity has been emphasized as the best potential marker, its spectral overlap with pain-related muscular responses is a potential drawback. Since muscle contractions...

The Sleep Hygiene Index (SHI) has shown adequate psychometric properties in samples from several countries but has not been validated in Spanish. The aims of the study were to translate the original (i.e., English) version of the SHI into Spanish and to evaluate the psychometric properties of this instrument (i.e., factor structure, internal consis...

Although emotion regulation has been proposed to be crucial for empathy, investigations on emotion regulation have been primarily limited to intrapersonal processes, leaving the interpersonal processes of self-regulation rather unexplored. Moreover, studies showed that emotion regulation and empathy are related with increased autonomic activation....

Background Lockdown has been one of the major worldwide strategies to control the spread of coronavirus disease 2019 (COVID-19). Its consequences on the well-being of individuals needs to be better understood. The objective of this work was to evaluate the impact of lockdown on the well-being of a general population and the factors associated with...

Pain sensation is characterized by abrupt changes in central nervous system activity producing autonomic reactivity. While clinical hypnosis has demonstrated its benefits for children in pain management, it is not clear whether hypnosis modulated autonomic pain response in children in clinical conditions. Here, we studied autonomic responses under...

New findings: What is the central question of this study ? Can Granger causality analysis of RR intervals, systolic blood pressure, and respiration evidence different physiological mechanisms induced during thermoneutral water immersion, 6° head-down tilt, and supine position tests, that are not accessible using traditional heart rate variability...

Purpose Thermoneutral head-out water immersion (WI) and 6° head-down tilt (HDT) have been considered as suitable models to increase central blood volume and simulate autonomic cardiovascular adaptations to microgravity, swimming or scuba diving. However, any differences in autonomic cardiovascular adaptations are still unclear. In this study, we hy...

Empathetic verbal feedback from others has been shown to alleviate the intensity of experimental pain. To investigate the brain changes associated with this effect, we conducted 3T-fMRI measurements in 30 healthy subjects who received painful thermal stimuli on their left hand while overhearing empathetic, neutral or unempathetic comments, supposed...

Objectives: This study examined the differences in cognitive function between middle-aged and older adults with insomnia disorder, insomnia symptoms only or no insomnia symptoms, in the context of other health and lifestyle factors. Methods: 28,485 participants >45 years completed questionnaires, physical examinations, and neuropsychological tes...

Background: The use of quantitative sensory testing (QST) in multicenter studies has been quite limited, due in part to lack of standardized procedures among centers. Aim: The aim of this study was to assess the application of the capsaicin pain model as a surrogate experimental human model of neuropathic pain in different centers and verify the va...

Objective: Differential diagnosis between sleep-related epileptic seizures and NREM parasomnia remains challenging. Pathophysiological markers to differentiate both conditions are needed. Activation of autonomic system is present in arousal reactions and epileptic seizures. Our study investigated whether cardiac reactivity differed between arousal...

Introduction Due to limited information from scalp electroencephalographic (EEG) recordings, brain areas driving changes in cardiac rhythm during Temporal lobe (TL) seizures are not clearly identified. Using stereotactic EEG (SEEG) recordings, we aimed at identifying which of the brain regions involved in autonomic control trigger ictal tachycardia...

Introduction Fibromyalgia is a common and complex chronic pain syndrome, characterized by widespread musculoskeletal pain and insomnia. It is now well established that lack of sleep is a risk factor of cardiovascular mortality. One of the potential mechanisms is the alteration in autonomic control of the cardiovascular system, marked by a diurnal a...

Introduction This study investigated interoception in fibromyalgia (FM), a disorder characterized by chronic pain accompanied by mood deregulation. Based on observations on the relationship between somatosensory processing and pain in FM and considering the affective symptoms of this disorder, we tested in FM three dimensions of interoception: inte...

Although modulation of cardiac activity may be influenced by several factors, interaction between autonomic nociceptive responses and the high-level of cortical processes is not clearly understood. Here, we studied in 26 subjects whether empathetic or unempathetic contexts could interact with autonomic pain responses. RR intervals variability was u...

The placebo effect is a psychobiological phenomenon producing clinical benefits attributed to a wide range of neurobiological mechanisms. Independently from placebo effects, these mechanisms may also be under the influence of processes that can take place during sleep. The relationship between sleep and placebo effects has received very little atte...

Aims: To identify structural changes in gray matter in suspected migraine generators (the hypothalamus and/or brainstem nuclei) and pain pathways and to evaluate whether structural changes in migraine are definitive or resolve with age. Methods: Voxel-based morphometry (VBM) was used to assess differences in gray matter between 39 healthy contro...

The physiological and behavioural effects of empathy for other's pain have been widely investigated, while the opposite situation, i.e. the influence on one's pain of empathetic feedback from others, remains largely unexplored. Here, we assessed whether and how empathetic and unempathetic comments from observers modulate pain and associated vegetat...

Pupillary diameter (PD) varies under the influence of both the sympathetic and parasympathetic systems, increasing proportionally to pain intensity. Such variations however should not be confused with pupillary fluctuations, which refer to the fast and permanent PD fluctuations induced by the ongoing interplay between the sympathetic and parasympat...

Background After 15 years of research about the link between sleep apnea and brain structure, no clear evidence can be noticed. In the same way, the influence of treatment is unclear, particularly in elderly. Aims and objectives The aim of this study is to investigate the grey matter differences related to sleep apnea and treatment in elderly subj...

Objectif Le diagnostic differentiel entre epilepsie morpheique et parasomnie peut etre difficile en raison d’un recouvrement semiologique entre ces entites et d’un signal electroencephalographique (EEG) souvent artefacte. Ces evenements sont associes a une reaction vegetative cardiovasculaire dont la dynamique reste mal connue. Nous avons etudie si...

Since the pioneering studies of the 1960s, heart rate variability (HRV) has become an increasingly used non-invasive tool for examining cardiac autonomic functions and dysfunctions in various populations and conditions. Many calculation methods have been developed to address these issues, each with their strengths and weaknesses. Although, its inte...

Objective Identify pain markers remains a major scientific and medical problem. In this view, we studied the dynamics of central and autonomic responses to tonic painful stimuli. Methods Twelve healthy subjects underwent 2 tonic painful (hand electrical stimulations and 10°C water immersion) and 2 non-painful (hand 15 °C water immersion and stress...

Objective The aim of the present study was to assess (1) autonomic changes and (2) which cerebral regions, engaged in autonomic control such as insula, amygdala, and hippocampus are involved in vegetative cardiac changes during temporal lobe seizures. Methods fifty nine temporal lobe seizures in 9 patients were studied for presurgical evaluation o...

The placebo effect is a neurobiological and psychophysiological process known to influence perceived pain relief. Optimization of placebo analgesia may contribute to the clinical efficacy and effectiveness of medication for acute and chronic pain management. We know that the placebo effect operates through two main mechanisms, expectations and lear...

Psychophysical and polysomnographic data. (XLSX)

Key points: Sleep spindle are usually considered to play a major role in inhibiting sensory inputs. Using nociceptive stimuli in humans, we tested the effect of spindles on behavioural, autonomic and cortical responses in two experiments using surface and intracerebral electroencephalographic recordings. We found that sleep spindles do not prevent...

Sleep is divided into two main sleep stages: (1) non-rapid eye movement sleep (non-REMS), characterized among others by reduced global brain activity; and (2) rapid eye movement sleep (REMS), characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV) analysis, which is widely used to explore auton...

The placebo response is a psychobiological phenomenon for clinical benefits following the administration of an inert substance whatever its form. This phenomenon can be attributed to a wide range of neurobiological processes, such as expectations of relief, the Pavlovian conditioning and learning, emotional regulation, and reward mechanisms, which...

Objective: The present study provides a functional mapping of vestibular responses in the human insular cortex. Methods: A total of 642 electrical stimulations of the insula were performed in 219 patients, using stereotactically implanted depth electrodes, during the presurgical evaluation of drug-refractory partial epilepsy. We retrospectively...

Alteration in cardiac autonomic activity during sleep is a common feature of sleep disorders. Diurnal sympathetic overactivity is a possible consequence and could contribute to future cardiovascular complications. The aim of this study is to assess the relationship between cardiac autonomic activity during sleep and diurnal autonomic cardiovascular...

The placebo response is a psychobiological phenomenon for clinical benefits following the administration of an inert substance whatever its form. This phenomenon can be attributed to a wide range of neurobiological processes, such as expectations of relief, the Pavlovian conditioning and learning, emotional regulation, and reward mechanisms, which...

The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasym-pathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart...

Autonomic dysfunction is recognized to contribute to cardiovascular consequences in obstructive sleep apnea/hypopnea syndrome (OSAHS) patients who present predominant cardiovascular sympathetic activity that persists during wakefulness. Here, we examined 1) the factors that influence sympathetic cardiac modulation in response to apneas/hypopneas; a...

Aims: Sleep fragmentation is a landmark of sleep disorders, because microarousals are systematically associated with sympathetic surges (i.e., sympathetic arousals). However, the impact of sympathetic sleep fragmentation on blood pressure (BP) remains understudied. We assessed the relationships between 24 h ambulatory BP monitoring, the autonomic...

Chronic pain is a highly prevalent post-concussion symptom occurring in a majority of mild traumatic brain injury (mTBI) patients. About half of mTBI patients report sleep-wake disturbances. It is known that pain can alter sleep quality in this population, but the interaction between pain and sleep is not fully understood. This study aimed to ident...

After the age of 65 yrs the specific impact of unrecognised sleep-related breathing disorders (SRBD) on 24-h blood pressure (BP) levels remains under debate. We tested the cross-sectional relationship between the severity of obstructive sleep apnoea/hypopnoea (OSAH) and the increase of BP using ambulatory BP monitoring (ABPM) in the PROOF (PROgnost...

To evaluate the ability of the heart rate power spectral density of the very low frequency component expressed as a percentage of the total power spectral band (%VLFI) to diagnose obstructive sleep apnoea (OSA) in the elderly. Eight hundred and thirty-two subjects aged 68.5±0.8 years were selected from the participants of a 7-year cross-sectional s...

Obstructive sleep apnea syndrome (OSA) has been recently considered as a cause and a component of the metabolic syndrome (MetS), previous studies showing the presence of OSA in about half of middle-aged patients having MetS. To date, no study has considered the association of OSA and MetS in the elderly. In this study we examine the prevalence of M...

Pulse transit time (PPT) has been introduced as a useful screening tool to diagnose sleep disordered breathing (SDB). Since the prevalence of SDB increases with age, the question is whether PTT could be used to diagnose SDB in the elderly. We assess the effectiveness of PTT for SDB screening in a large healthy elderly population. Community-based sa...

The high prevalence of sleep disordered breathing (SDB) among heart diseases patients becomes increasingly recognized. A reliable exploring tool of SDB well adapted to cardiologists practice would be very useful for the management of these patients. We assessed a novel multi-modal electrocardiogram (ECG) Holter which incorporated both thoracic impe...

The autonomic nervous system (ANS) reacts to nociceptive stimulation during sleep, but whether this reaction is contingent to cortical arousal, and whether one of the autonomic arms (sympathetic/parasympathetic) predominates over the other remains unknown. We assessed ANS reactivity to nociceptive stimulation during all sleep stages through heart r...

Purpose: Type 2 diabetes (T2D) is an important risk factor for heart failure. T2D is associated with the metabolic syndrome, encompassing cardiovascular risk factors such as obesity, insulin resistance and dyslipidemia, factors also associated with left ventricular diastolic dysfunction. Patients with T2D have elevated plasma levels of free fatty a...

Obstructive sleep apnoea (OSA) affects females and males differently, and increases in prevalence with age. The aim of the present study was to characterise clinical, anthropometric and polygraphic sex differences in a large elderly OSA population. A total of 641 subjects aged 68 yrs were examined. Measurements of fat mass, using dual-energy X-ray...

In the elderly, obstructive sleep apnea (OSA) is frequently under diagnosed. This study was undertaken to assess the accuracy of the Berlin questionnaire to diagnose OSA in a large healthy elderly population. Six hundred forty-three participants aged 65.6 years were examined. All subjects completed the Berlin questionnaire and underwent at-home res...

Several studies have correlated the ratio of the very low frequency power spectral density of heart rate increment (%VLFI) with obstructive sleep apnoea syndrome (OSAS). However, patients with impaired heart rate variability may exhibit large variations of heart rate increment (HRI) spectral pattern and alter the screening accuracy of the method. T...

It was already established that exposure to hyperbaric conditions induces vagal-depended bradycardia but field study on autonomic nervous system (ANS) activity during self-contained underwater breathing apparatus (SCUBA) diving is lacking. The aim of the present study was to evaluate ANS modifications during real recreational SCUBA diving using hea...