Alice Guyon | École Normale Supérieure (original) (raw)
Papers by Alice Guyon
Journal of Eye Movement Research
The eyes are in constant movement to optimize the interpretation of the visual scene by the brain... more The eyes are in constant movement to optimize the interpretation of the visual scene by the brain. Eye movements are controlled by complex neural networks that interact with the rest of the brain. The direction of our eye movements could thus be influenced by our cognitive activity (imagination, internal dialogue, memory, etc.). A given cognitive activity could then cause the gaze to move in a specific direction (a brief movement that would be instinctive and unconscious). Neuro Linguistic Programming (NLP), which was developed in the 1970s by Richard Bandler and John Grinder (psychologist and linguist respectively), issued a comprehensive theory associating gaze directions with specific mental tasks. According to this theory, depending on the visual path observed, one could go back to the participant's thoughts and cognitive processes. Although NLP is widely used in many disciplines (communication, psychology, psychotherapy, marketing, etc), to date, few scientific studies have...
Staps, 2021
La definition des pratiques des arts energetiques indiens ou chinois se heurte a un double proble... more La definition des pratiques des arts energetiques indiens ou chinois se heurte a un double probleme, taxinomique et axiologique. Elle est au cœur d’un dialogue des cultures scientifiques d’Orient et d’Occident qui permet de depasser le « choc » des civilisations. Dans cet article, nous proposons un bilan d’etape sur les bienfaits de ces pratiques du point de vue des neurosciences et des sciences cognitives, qui pourrait contribuer a reconcilier le mecanisme et le vitalisme, aider a depasser le dualisme de la matiere et de l’esprit, l’opposition qualite/quantite, holisme/reductionnisme... Bref, a marier les paradigmes de la science occidentale et de la science orientale pour s’inscrire dans une perspective de sport durable.
Translational Psychiatry, 2018
Major depression is a psychiatric disorder with complex etiology. About 30% of depressive patient... more Major depression is a psychiatric disorder with complex etiology. About 30% of depressive patients are resistant to antidepressants that are currently available, likely because they only target the monoaminergic systems. Thus, identification of novel antidepressants with a larger action spectrum is urgently required. Epidemiological data indicate high comorbidity between metabolic and psychiatric disorders, particularly obesity and depression. We used a well-characterized anxiety/depressive-like mouse model consisting of continuous input of corticosterone for seven consecutive weeks. A panel of reliable behavioral tests were conducted to assessing numerous facets of the depression-like state, including anxiety, resignation, reduced motivation, loss of pleasure, and social withdrawal. Furthermore, metabolic features including weight, adiposity, and plasma biological parameters (lipids, adipokines, and cytokines) were investigated in corticosterone-treated mice. Our data show that chronic administration of corticosterone induced the parallel onset of metabolic and behavioral dysfunctions in mice. AdipoRon, a potent adiponectin receptor agonist, prevented the corticosterone-induced early onset of moderate obesity and metabolic syndromes. Moreover, in all the behavioral tests, daily treatment with AdipoRon successfully reversed the corticosterone-induced depression-like state in mice. AdipoRon exerted its pleiotropic actions on various systems including hippocampal neurogenesis, serotonergic neurotransmission, neuroinflammation, and the tryptophan metabolic pathway, which can explain its antidepressant properties. Our study highlights the pivotal role of the adiponergic system in the development of both metabolic and psychiatric disorders. AdipoRon may constitute a promising novel antidepressant.
In developed societies, the number of people diagnosed with chronic stress-related illnesses has ... more In developed societies, the number of people diagnosed with chronic stress-related illnesses has risen rapidly in recent years. To meet the increasing demand for relaxation and well-being, several companies have developed relaxation installations to be used within business premises or in public locations. The effects of such devices on physiological and psychological parameters have not been scientifically tested yet. This pilot study (N=40) evaluates the variations of 4 physiological and 11 psychological parameters on four different groups, three of them using a different rapid (15 minute) sensorial immersion relaxation devices and a control group using no device. The objective of the study was to identify the psychological and psychological parameters of interest and to study the effects of the devices on these parameters. Physiological parameters measured included heart rate, blood pressure, SpO2 and posture. Psychological parameters included an anxiety survey and four numerical ...
Journal of Neuroimmunology, 2010
Inflammatory response represents one of the first immune processes following injury. It is charac... more Inflammatory response represents one of the first immune processes following injury. It is characterized by the production of various molecules that initiate the recruitment of immune cells to the lesion sites, including in the brain. Accordingly, in acute brain trauma, such as stroke, as well as during chronic affections like multiple sclerosis or Alzheimer's disease, inflammation occurs in order to "clean up" the lesion and to limit its area. Nevertheless, prolonged and sustained inflammation may have cytotoxic effects, aggravating the incidence and the severity of the disease. Among molecules produced during inflammation associated to neuronal death, monocyte chemoattractant proteins (MCPs) seem to be particularly important. This review will focus on the current knowledge about one of the MCPs, CCL2, and its cognate receptor, CCR2, both expressed in physiological conditions and during neurodegenerative diseases.
The Hippocampus - Plasticity and Functions, Jul 11, 2018
Brain plasticity is profoundly impacted by one's living environment. The hippocampus, involved in... more Brain plasticity is profoundly impacted by one's living environment. The hippocampus, involved in learning and memory, is highly susceptible to plasticity. Raising rodents in an "enriched environment" (EE) increases learning and memorization aptitudes and decreases the anxiety of the animals. EE consists of a combination of running wheels for voluntary physical exercise, complex inanimate toys, nests, mazes, etc. all of which favor sensory stimulations and social enrichment. EE housing concomitantly increases proliferation and survival of neurons and glia in the dentate gyrus of the hippocampus, induces changes in neuronal morphology, modifies synaptic plasticity, and favors angiogenesis. The mechanisms underlying the effects of EE on plasticity, which have recently been investigated are reviewed here, including the role of glia, the involvement of molecular factors including neurotransmitters (glutamate), neurotrophic factors (BDNF), adipokines (leptin and adiponectin), chemokines, cytokines, and hormones (corticosteroid and thyroid hormones), and at a higher level, the various systems involved (neural networks and hormonal systems). We emphasize recent findings that demonstrate the major role of the immune system in modulating EE-induced changes to hippocampal plasticity. This process involves a variety of immune cells (including macrophages, microglia, natural killer, B-cells, and T-cells), although the mechanisms are yet to be fully elucidated.
Neuroimmunomodulation
HIGHLIHTS-In the choroid plexus, CD4 + T cells regulate the expression of transthyretin (TTR), th... more HIGHLIHTS-In the choroid plexus, CD4 + T cells regulate the expression of transthyretin (TTR), the major transporter of thyroxine (T4) to the brain parenchyma.-CD4 + T cells influence EE-induced hippocampus plasticity via the thyroid hormone signaling.-Close interactions between the immune and neuroendocrine systems are influencing the brain plasticity and function.
Rapid relaxation devices developed by private companies propose rapid solutions to fight against ... more Rapid relaxation devices developed by private companies propose rapid solutions to fight against stress or anxiety. However, there have been insufficient scientific studies on these devices. In a previous article, we evaluated the variation of 15 physiological and psychological parameters before and after relaxation in 4 groups of participants using 3 different rapid (15 minute) relaxation devices with sensorial immersion and a control group using no device. This pilot study included 40 participants, 12 males and 28 females, aged 27-68 years old with an average of 42.7 ± 11.5 years old and showed that some parameters were more relevant for the analysis of these relaxation devices and suggested some differences in the relaxation processes between devices. We hypothesized that by analyzing physiological parameters recorded during the rapid relaxation process in the same population, we could unravel the previously observed pre-post treatment variations. The measurements included brain ...
Rapid relaxation installations in order to reduce stress appear more and more in public or work p... more Rapid relaxation installations in order to reduce stress appear more and more in public or work places. However, the effects of such devices on physiological and psychological parameters have not been scientifically tested yet. This pilot study (N=40) evaluates the variations of vocal speech and facial emotions parameters in 3-minute videos of participant recorded just before and after relaxation, on four different groups, three of them using a different rapid (15 minutes) sensorial immersion relaxation devices and a control group using no device. Vocal speech parameters included sound duration, pause mean duration, sound duration ratio, mean vocal frequency (F0), standard deviation of F0, minimum and maximum of F0, jitter and shimmer. Facial emotion analysis included neutral, happy, sad, surprised, angry, disgusted, scared, contempt, valence and arousal. The objective of this study is to evaluate different parameters of the automated vocal and facial emotions analysis that could be...
Notre etude porte sur les proprietes intrinseques et synaptiques des neurones principaux du thala... more Notre etude porte sur les proprietes intrinseques et synaptiques des neurones principaux du thalamus, a savoir les neurones thalamo-corticaux de deux noyaux specifiques thalamiques, le corps genouille lateral, noyau de relais visuel, et le complexe ventro basal, relais somato sensoriel, ainsi que des neurones du noyau reticule thalamique. Une attention particuliere a ete accordee aux courants calciques dependants du potentiel, notamment le courant calcique a bas seuil qui joue un role preponderant dans les decharges en bouffee et les phenomenes oscillatoires de ces neurones. Ce travail a ete realise sur des preparations in vitro, tranches et cellules dissociees de thalamus, en utilisant essentiellement la technique de patch-clamp en configuration cellule entiere
Nature Biotechnology
Vagus nerve stimulation can ameliorate autoimmune diseases such as rheumatoid arthritis by modula... more Vagus nerve stimulation can ameliorate autoimmune diseases such as rheumatoid arthritis by modulation of the immune system. Its efficacy for the treatment of type 1 diabetes has not been explored, in part because the nerves projecting to the pancreatic lymph nodes (pLNs) in mice are unmapped. Here, we map the nerve projecting to the pancreas and pLNs in mice and use a minimally invasive surgical procedure to implant micro-cuff electrodes onto the nerve. Pancreatic nerve electrical stimulation (PNES) resulted in β-adrenergic receptor-mediated-accumulation of B and T cells in pLNs and reduced production of pro-inflammatory cytokines following lipopolysaccharide stimulation. Autoreactive T cells showed reduced proliferation in pLNs of mice receiving PNES as compared to sham controls. In a spontaneous mouse model of autoimmune diabetes, PNES inhibited disease progression in diabetic mice.Autoimmune diabetes in mice is averted by electrically stimulating the nerve projecting to the pancreas.
Medical & Biological Engineering & Computing, 2015
Frontiers in Synaptic Neuroscience
Living in an enriched environment (EE) benefits health by acting synergistically on various biolo... more Living in an enriched environment (EE) benefits health by acting synergistically on various biological systems including the immune and the central nervous systems. The dialog between the brain and the immune cells has recently gained interest and is thought to play a pivotal role in beneficial effects of EE. Recent studies show that T lymphocytes have an important role in hippocampal plasticity, learning, and memory, although the precise mechanisms by which they act on the brain remain elusive. Using a mouse model of EE, we show here that CD4 + T cells are essential for spinogenesis and glutamatergic synaptic function in the CA of the hippocampus. However, CD4 + lymphocytes do not influence EE-induced neurogenesis in the DG of the hippocampus, by contrast to what we previously demonstrated for CD8 + T cells. Importantly, CD4 + T cells located in the choroid plexus have a specific transcriptomic signature as a function of the living environment. Our study highlights the contribution of CD4 + T cells in the brain plasticity and function.
Brain, behavior, and immunity, 2018
Enriched environment (EE) induces plasticity changes in the brain. Recently, CD4 T cells have bee... more Enriched environment (EE) induces plasticity changes in the brain. Recently, CD4 T cells have been shown to be involved in brain plasticity processes. Here, we show that CD8 T cells are required for EE-induced brain plasticity in mice, as revealed by measurements of hippocampal volume, neurogenesis in the DG of the hippocampus, spinogenesis and glutamatergic synaptic function in the CA of the hippocampus. As a consequence, EE-induced behavioral benefits depend, at least in part, on CD8 T cells. In addition, we show that spleen CD8 T cells from mice housed in standard environment (SE) and EE have different properties in terms of 1) TNFα release after in vitro CD3/CD28 or PMA/Iono stimulation 2) in vitro proliferation properties 3) CD8 CD44 CD62L and CD62L T cells repartition 4) transcriptomic signature as revealed by RNA sequencing. CD8 T cells purified from the choroid plexus of SE and EE mice also exhibit different transcriptomic profiles as highlighted by single-cell mRNA sequenci...
Frontiers in cellular neuroscience, 2017
We recently reported that increased levels of Adiponectin (ApN) in the brain led to microglia phe... more We recently reported that increased levels of Adiponectin (ApN) in the brain led to microglia phenotype and activation state regulation, thus reducing both global brain inflammation and depressive-like behaviors in mice. Apart from this, little is known on ApN molecular effects on microglia, although these cells are crucial in both physiological and pathological processes. Here we fill this gap by studying the effects and targets of ApN toward neuroinflammation. Our findings suggest that ApN deficiency in mice leads to a higher sensitivity of mice to neuroinflammation that is due to enhanced microglia responsiveness to a pro-inflammatory challenge. Moreover, we show that globular ApN (gApN) exerts direct anti-inflammatory actions on microglia by reducing IL-1β, IL-6, and TNFα synthesis. , gApN anti-inflammatory properties are confirmed in brain-sorted microglia, primary cultured and microglia cell line (BV2), but are not observed on astrocytes. Our results also show that gApN blocks...
![Research paper thumbnail of [Adiponectin: an endogenous molecule with anti-inflammatory and antidepressant properties?]](https://attachments.academia-assets.com/70322733/thumbnails/1.jpg)
](Medecine sciences : M/S, 2018
Adiponectin (ApN) is a hormone produced by adipose tissue, yet the plasma level of ApN is decreas... more Adiponectin (ApN) is a hormone produced by adipose tissue, yet the plasma level of ApN is decreased in overweight and obese people, as well as in people with diabetes. In the periphery, this decrease in circulating levels of ApN induces the establishment of a chronic low-grade inflammatory state and is involved in the development of insulin resistance and atheromas. Conversely, "favorable" living conditions, weight loss and regular physical exercise increase ApN blood concentration. Some forms of ApN can reach the brain parenchyma through the cerebrospinal fluid. In the brain, the increase in ApN exerts powerful antidepressant and anxiolytic effects, in particular by fighting against neuroinflammation.
EMBO reports, Dec 1, 2016
Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associate... more Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associated with infection. While inflammatory responses were suggested to be instrumental in the loss of appetite and body weight, the molecular underpinning remains unknown. Here, we show that systemic or central lipopolysaccharide (LPS) injection results in specific hypothalamic changes characterized by a precocious increase in the chemokine ligand 2 (CCL2) followed by an increase in pro-inflammatory cytokines and a decrease in the orexigenic neuropeptide melanin-concentrating hormone (MCH). We therefore hypothesized that CCL2 could be the central relay for the loss in body weight induced by the inflammatory signal LPS. We find that central delivery of CCL2 promotes neuroinflammation and the decrease in MCH and body weight. MCH neurons express CCL2 receptor and respond to CCL2 by decreasing both electrical activity and MCH release. Pharmacological or genetic inhibition of CCL2 signaling opposes...
Journal of Neurochemistry, Aug 1, 2007
We recently demonstrated that dopaminergic (DA) neurons of the rat substantia nigra constitutivel... more We recently demonstrated that dopaminergic (DA) neurons of the rat substantia nigra constitutively expressed CXCR4, receptor for the chemokine stromal cell-derived factor-1 (SDF-1)/ CXCL12 (SDF-1). To check the physiological relevance of such anatomical observation, in vitro and in vivo approaches were used. Patch clamp recording of DA neurons in rat substantia nigra slices revealed that SDF-1 (10 nmol/L) induced: (i) a depolarization and increased action potential frequency; and (ii) switched the firing pattern of depolarized DA neurons from a tonic to a burst firing mode. This suggests that SDF-1 could increase DA release from neurons. Consistent with this hypothesis, unilateral intranigral injection of SDF-1 (50 ng) in freely moving rat decreased DA content and increased extracellular concentrations of DA and metabolites in the ipsilateral dorsal striatum, as shown using microdialysis. Furthermore, intranigral SDF-1 injection induced a contralateral circling behavior. These effects of SDF-1 were mediated via CXCR4 as they were abrogated by administration of a selective CXCR4 antagonist. Altogether, these data demonstrate that SDF-1, via CXCR4, activates nigrostriatal DA transmission. They show that the central functions of chemokines are not restricted, as originally thought, to neuroinflammation, but extend to neuromodulatory actions on well-defined neuronal circuits in non-pathological conditions.
Journal of Eye Movement Research
The eyes are in constant movement to optimize the interpretation of the visual scene by the brain... more The eyes are in constant movement to optimize the interpretation of the visual scene by the brain. Eye movements are controlled by complex neural networks that interact with the rest of the brain. The direction of our eye movements could thus be influenced by our cognitive activity (imagination, internal dialogue, memory, etc.). A given cognitive activity could then cause the gaze to move in a specific direction (a brief movement that would be instinctive and unconscious). Neuro Linguistic Programming (NLP), which was developed in the 1970s by Richard Bandler and John Grinder (psychologist and linguist respectively), issued a comprehensive theory associating gaze directions with specific mental tasks. According to this theory, depending on the visual path observed, one could go back to the participant's thoughts and cognitive processes. Although NLP is widely used in many disciplines (communication, psychology, psychotherapy, marketing, etc), to date, few scientific studies have...
Staps, 2021
La definition des pratiques des arts energetiques indiens ou chinois se heurte a un double proble... more La definition des pratiques des arts energetiques indiens ou chinois se heurte a un double probleme, taxinomique et axiologique. Elle est au cœur d’un dialogue des cultures scientifiques d’Orient et d’Occident qui permet de depasser le « choc » des civilisations. Dans cet article, nous proposons un bilan d’etape sur les bienfaits de ces pratiques du point de vue des neurosciences et des sciences cognitives, qui pourrait contribuer a reconcilier le mecanisme et le vitalisme, aider a depasser le dualisme de la matiere et de l’esprit, l’opposition qualite/quantite, holisme/reductionnisme... Bref, a marier les paradigmes de la science occidentale et de la science orientale pour s’inscrire dans une perspective de sport durable.
Translational Psychiatry, 2018
Major depression is a psychiatric disorder with complex etiology. About 30% of depressive patient... more Major depression is a psychiatric disorder with complex etiology. About 30% of depressive patients are resistant to antidepressants that are currently available, likely because they only target the monoaminergic systems. Thus, identification of novel antidepressants with a larger action spectrum is urgently required. Epidemiological data indicate high comorbidity between metabolic and psychiatric disorders, particularly obesity and depression. We used a well-characterized anxiety/depressive-like mouse model consisting of continuous input of corticosterone for seven consecutive weeks. A panel of reliable behavioral tests were conducted to assessing numerous facets of the depression-like state, including anxiety, resignation, reduced motivation, loss of pleasure, and social withdrawal. Furthermore, metabolic features including weight, adiposity, and plasma biological parameters (lipids, adipokines, and cytokines) were investigated in corticosterone-treated mice. Our data show that chronic administration of corticosterone induced the parallel onset of metabolic and behavioral dysfunctions in mice. AdipoRon, a potent adiponectin receptor agonist, prevented the corticosterone-induced early onset of moderate obesity and metabolic syndromes. Moreover, in all the behavioral tests, daily treatment with AdipoRon successfully reversed the corticosterone-induced depression-like state in mice. AdipoRon exerted its pleiotropic actions on various systems including hippocampal neurogenesis, serotonergic neurotransmission, neuroinflammation, and the tryptophan metabolic pathway, which can explain its antidepressant properties. Our study highlights the pivotal role of the adiponergic system in the development of both metabolic and psychiatric disorders. AdipoRon may constitute a promising novel antidepressant.
In developed societies, the number of people diagnosed with chronic stress-related illnesses has ... more In developed societies, the number of people diagnosed with chronic stress-related illnesses has risen rapidly in recent years. To meet the increasing demand for relaxation and well-being, several companies have developed relaxation installations to be used within business premises or in public locations. The effects of such devices on physiological and psychological parameters have not been scientifically tested yet. This pilot study (N=40) evaluates the variations of 4 physiological and 11 psychological parameters on four different groups, three of them using a different rapid (15 minute) sensorial immersion relaxation devices and a control group using no device. The objective of the study was to identify the psychological and psychological parameters of interest and to study the effects of the devices on these parameters. Physiological parameters measured included heart rate, blood pressure, SpO2 and posture. Psychological parameters included an anxiety survey and four numerical ...
Journal of Neuroimmunology, 2010
Inflammatory response represents one of the first immune processes following injury. It is charac... more Inflammatory response represents one of the first immune processes following injury. It is characterized by the production of various molecules that initiate the recruitment of immune cells to the lesion sites, including in the brain. Accordingly, in acute brain trauma, such as stroke, as well as during chronic affections like multiple sclerosis or Alzheimer's disease, inflammation occurs in order to "clean up" the lesion and to limit its area. Nevertheless, prolonged and sustained inflammation may have cytotoxic effects, aggravating the incidence and the severity of the disease. Among molecules produced during inflammation associated to neuronal death, monocyte chemoattractant proteins (MCPs) seem to be particularly important. This review will focus on the current knowledge about one of the MCPs, CCL2, and its cognate receptor, CCR2, both expressed in physiological conditions and during neurodegenerative diseases.
The Hippocampus - Plasticity and Functions, Jul 11, 2018
Brain plasticity is profoundly impacted by one's living environment. The hippocampus, involved in... more Brain plasticity is profoundly impacted by one's living environment. The hippocampus, involved in learning and memory, is highly susceptible to plasticity. Raising rodents in an "enriched environment" (EE) increases learning and memorization aptitudes and decreases the anxiety of the animals. EE consists of a combination of running wheels for voluntary physical exercise, complex inanimate toys, nests, mazes, etc. all of which favor sensory stimulations and social enrichment. EE housing concomitantly increases proliferation and survival of neurons and glia in the dentate gyrus of the hippocampus, induces changes in neuronal morphology, modifies synaptic plasticity, and favors angiogenesis. The mechanisms underlying the effects of EE on plasticity, which have recently been investigated are reviewed here, including the role of glia, the involvement of molecular factors including neurotransmitters (glutamate), neurotrophic factors (BDNF), adipokines (leptin and adiponectin), chemokines, cytokines, and hormones (corticosteroid and thyroid hormones), and at a higher level, the various systems involved (neural networks and hormonal systems). We emphasize recent findings that demonstrate the major role of the immune system in modulating EE-induced changes to hippocampal plasticity. This process involves a variety of immune cells (including macrophages, microglia, natural killer, B-cells, and T-cells), although the mechanisms are yet to be fully elucidated.
Neuroimmunomodulation
HIGHLIHTS-In the choroid plexus, CD4 + T cells regulate the expression of transthyretin (TTR), th... more HIGHLIHTS-In the choroid plexus, CD4 + T cells regulate the expression of transthyretin (TTR), the major transporter of thyroxine (T4) to the brain parenchyma.-CD4 + T cells influence EE-induced hippocampus plasticity via the thyroid hormone signaling.-Close interactions between the immune and neuroendocrine systems are influencing the brain plasticity and function.
Rapid relaxation devices developed by private companies propose rapid solutions to fight against ... more Rapid relaxation devices developed by private companies propose rapid solutions to fight against stress or anxiety. However, there have been insufficient scientific studies on these devices. In a previous article, we evaluated the variation of 15 physiological and psychological parameters before and after relaxation in 4 groups of participants using 3 different rapid (15 minute) relaxation devices with sensorial immersion and a control group using no device. This pilot study included 40 participants, 12 males and 28 females, aged 27-68 years old with an average of 42.7 ± 11.5 years old and showed that some parameters were more relevant for the analysis of these relaxation devices and suggested some differences in the relaxation processes between devices. We hypothesized that by analyzing physiological parameters recorded during the rapid relaxation process in the same population, we could unravel the previously observed pre-post treatment variations. The measurements included brain ...
Rapid relaxation installations in order to reduce stress appear more and more in public or work p... more Rapid relaxation installations in order to reduce stress appear more and more in public or work places. However, the effects of such devices on physiological and psychological parameters have not been scientifically tested yet. This pilot study (N=40) evaluates the variations of vocal speech and facial emotions parameters in 3-minute videos of participant recorded just before and after relaxation, on four different groups, three of them using a different rapid (15 minutes) sensorial immersion relaxation devices and a control group using no device. Vocal speech parameters included sound duration, pause mean duration, sound duration ratio, mean vocal frequency (F0), standard deviation of F0, minimum and maximum of F0, jitter and shimmer. Facial emotion analysis included neutral, happy, sad, surprised, angry, disgusted, scared, contempt, valence and arousal. The objective of this study is to evaluate different parameters of the automated vocal and facial emotions analysis that could be...
Notre etude porte sur les proprietes intrinseques et synaptiques des neurones principaux du thala... more Notre etude porte sur les proprietes intrinseques et synaptiques des neurones principaux du thalamus, a savoir les neurones thalamo-corticaux de deux noyaux specifiques thalamiques, le corps genouille lateral, noyau de relais visuel, et le complexe ventro basal, relais somato sensoriel, ainsi que des neurones du noyau reticule thalamique. Une attention particuliere a ete accordee aux courants calciques dependants du potentiel, notamment le courant calcique a bas seuil qui joue un role preponderant dans les decharges en bouffee et les phenomenes oscillatoires de ces neurones. Ce travail a ete realise sur des preparations in vitro, tranches et cellules dissociees de thalamus, en utilisant essentiellement la technique de patch-clamp en configuration cellule entiere
Nature Biotechnology
Vagus nerve stimulation can ameliorate autoimmune diseases such as rheumatoid arthritis by modula... more Vagus nerve stimulation can ameliorate autoimmune diseases such as rheumatoid arthritis by modulation of the immune system. Its efficacy for the treatment of type 1 diabetes has not been explored, in part because the nerves projecting to the pancreatic lymph nodes (pLNs) in mice are unmapped. Here, we map the nerve projecting to the pancreas and pLNs in mice and use a minimally invasive surgical procedure to implant micro-cuff electrodes onto the nerve. Pancreatic nerve electrical stimulation (PNES) resulted in β-adrenergic receptor-mediated-accumulation of B and T cells in pLNs and reduced production of pro-inflammatory cytokines following lipopolysaccharide stimulation. Autoreactive T cells showed reduced proliferation in pLNs of mice receiving PNES as compared to sham controls. In a spontaneous mouse model of autoimmune diabetes, PNES inhibited disease progression in diabetic mice.Autoimmune diabetes in mice is averted by electrically stimulating the nerve projecting to the pancreas.
Medical & Biological Engineering & Computing, 2015
Frontiers in Synaptic Neuroscience
Living in an enriched environment (EE) benefits health by acting synergistically on various biolo... more Living in an enriched environment (EE) benefits health by acting synergistically on various biological systems including the immune and the central nervous systems. The dialog between the brain and the immune cells has recently gained interest and is thought to play a pivotal role in beneficial effects of EE. Recent studies show that T lymphocytes have an important role in hippocampal plasticity, learning, and memory, although the precise mechanisms by which they act on the brain remain elusive. Using a mouse model of EE, we show here that CD4 + T cells are essential for spinogenesis and glutamatergic synaptic function in the CA of the hippocampus. However, CD4 + lymphocytes do not influence EE-induced neurogenesis in the DG of the hippocampus, by contrast to what we previously demonstrated for CD8 + T cells. Importantly, CD4 + T cells located in the choroid plexus have a specific transcriptomic signature as a function of the living environment. Our study highlights the contribution of CD4 + T cells in the brain plasticity and function.
Brain, behavior, and immunity, 2018
Enriched environment (EE) induces plasticity changes in the brain. Recently, CD4 T cells have bee... more Enriched environment (EE) induces plasticity changes in the brain. Recently, CD4 T cells have been shown to be involved in brain plasticity processes. Here, we show that CD8 T cells are required for EE-induced brain plasticity in mice, as revealed by measurements of hippocampal volume, neurogenesis in the DG of the hippocampus, spinogenesis and glutamatergic synaptic function in the CA of the hippocampus. As a consequence, EE-induced behavioral benefits depend, at least in part, on CD8 T cells. In addition, we show that spleen CD8 T cells from mice housed in standard environment (SE) and EE have different properties in terms of 1) TNFα release after in vitro CD3/CD28 or PMA/Iono stimulation 2) in vitro proliferation properties 3) CD8 CD44 CD62L and CD62L T cells repartition 4) transcriptomic signature as revealed by RNA sequencing. CD8 T cells purified from the choroid plexus of SE and EE mice also exhibit different transcriptomic profiles as highlighted by single-cell mRNA sequenci...
Frontiers in cellular neuroscience, 2017
We recently reported that increased levels of Adiponectin (ApN) in the brain led to microglia phe... more We recently reported that increased levels of Adiponectin (ApN) in the brain led to microglia phenotype and activation state regulation, thus reducing both global brain inflammation and depressive-like behaviors in mice. Apart from this, little is known on ApN molecular effects on microglia, although these cells are crucial in both physiological and pathological processes. Here we fill this gap by studying the effects and targets of ApN toward neuroinflammation. Our findings suggest that ApN deficiency in mice leads to a higher sensitivity of mice to neuroinflammation that is due to enhanced microglia responsiveness to a pro-inflammatory challenge. Moreover, we show that globular ApN (gApN) exerts direct anti-inflammatory actions on microglia by reducing IL-1β, IL-6, and TNFα synthesis. , gApN anti-inflammatory properties are confirmed in brain-sorted microglia, primary cultured and microglia cell line (BV2), but are not observed on astrocytes. Our results also show that gApN blocks...
Medecine sciences : M/S, 2018
Adiponectin (ApN) is a hormone produced by adipose tissue, yet the plasma level of ApN is decreas... more Adiponectin (ApN) is a hormone produced by adipose tissue, yet the plasma level of ApN is decreased in overweight and obese people, as well as in people with diabetes. In the periphery, this decrease in circulating levels of ApN induces the establishment of a chronic low-grade inflammatory state and is involved in the development of insulin resistance and atheromas. Conversely, "favorable" living conditions, weight loss and regular physical exercise increase ApN blood concentration. Some forms of ApN can reach the brain parenchyma through the cerebrospinal fluid. In the brain, the increase in ApN exerts powerful antidepressant and anxiolytic effects, in particular by fighting against neuroinflammation.
EMBO reports, Dec 1, 2016
Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associate... more Sickness behavior defines the endocrine, autonomic, behavioral, and metabolic responses associated with infection. While inflammatory responses were suggested to be instrumental in the loss of appetite and body weight, the molecular underpinning remains unknown. Here, we show that systemic or central lipopolysaccharide (LPS) injection results in specific hypothalamic changes characterized by a precocious increase in the chemokine ligand 2 (CCL2) followed by an increase in pro-inflammatory cytokines and a decrease in the orexigenic neuropeptide melanin-concentrating hormone (MCH). We therefore hypothesized that CCL2 could be the central relay for the loss in body weight induced by the inflammatory signal LPS. We find that central delivery of CCL2 promotes neuroinflammation and the decrease in MCH and body weight. MCH neurons express CCL2 receptor and respond to CCL2 by decreasing both electrical activity and MCH release. Pharmacological or genetic inhibition of CCL2 signaling opposes...
Journal of Neurochemistry, Aug 1, 2007
We recently demonstrated that dopaminergic (DA) neurons of the rat substantia nigra constitutivel... more We recently demonstrated that dopaminergic (DA) neurons of the rat substantia nigra constitutively expressed CXCR4, receptor for the chemokine stromal cell-derived factor-1 (SDF-1)/ CXCL12 (SDF-1). To check the physiological relevance of such anatomical observation, in vitro and in vivo approaches were used. Patch clamp recording of DA neurons in rat substantia nigra slices revealed that SDF-1 (10 nmol/L) induced: (i) a depolarization and increased action potential frequency; and (ii) switched the firing pattern of depolarized DA neurons from a tonic to a burst firing mode. This suggests that SDF-1 could increase DA release from neurons. Consistent with this hypothesis, unilateral intranigral injection of SDF-1 (50 ng) in freely moving rat decreased DA content and increased extracellular concentrations of DA and metabolites in the ipsilateral dorsal striatum, as shown using microdialysis. Furthermore, intranigral SDF-1 injection induced a contralateral circling behavior. These effects of SDF-1 were mediated via CXCR4 as they were abrogated by administration of a selective CXCR4 antagonist. Altogether, these data demonstrate that SDF-1, via CXCR4, activates nigrostriatal DA transmission. They show that the central functions of chemokines are not restricted, as originally thought, to neuroinflammation, but extend to neuromodulatory actions on well-defined neuronal circuits in non-pathological conditions.