Executive function and prefrontal cortex in rats

The term executive function describes a set of high-level abilities that influence more basic motor, sensory and mnemonic processes. These functions include working memory, behavioural flexibility, inhibitory control, attentional processes and decision making. A large number of evidence, from human studies, non-human primates, rats and mice studies, has demonstrated a role for the prefrontal cortex in these higher cognitive processes. The central aim of this thesis was to investigate two important aspects of the cognitive executive control: working memory and behavioural flexibility. The experiments described in the first two empirical chapters present the design of new operant paradigms to study these processes. Two further empirical chapters consider the neurobiological basis of behavioural flexibility, with a particular emphasize on the infralimbic (IL) and prelimbic (PL) regions of the rat medial prefrontal cortex (mPFC). Although, the IL and PL regions have generally been considered as a single functional unit, empirical findings presented in this thesis provide evidence suggesting that the IL and PL mPFC can be viewed as independent but interactive regions with complementary roles in the control of behaviour. That is, the PL brings simple cue-outcome associations and more complex behavioural patterns under the modulatory influence of contextual, or other task-relevant, information and in contrast, the IL exerts an inhibitory influence over the PL biasing the animal towards simple, prepotent, learned or innate behavioural patterns.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Challenges Associated With the Civilian Reintegration of Soldiers With Chronic PTSD: A New Approach Integrating Psychological Resources and Values in Action Reappropriation

Background: In light of the psychological changes in an individual suffering from chronic Posttraumatic Stress Disorder (PTSD), questions are being raised in order to understand and facilitate recovery and a return to work. This is particularly challenging for soldiers suffering from chronic PTSD, who are often young individuals suffering from moral conflicts. A French military rehabilitation program proposes the broadening of the relationships between recovery and reintegration by incorporating approaches from the field of positive psychology for soldiers with chronic PTSD. The aim of the study was to evaluate (i) the psychological resources which remain sustainable for these trauma exposed soldiers according to their PTSD symptoms, (ii) the dynamics of resource reappropriation after the military rehabilitation program, which focuses on values in action (VIA) as character strengths, and (iii) how these resources and their reappropriation facilitate civilian professional reintegration.Method: We conducted a prospective study with 56 trauma exposed soldiers with a clinical diagnosis of chronic PTSD. PTSD severity and psychological resources (optimism, mindfulness, well-being, motivation, self-esteem, and VIA) were assessed before and after the rehabilitation program. After the identification of resource profiles, we analyzed the impact of the program on resource levels and successful reintegration into a civilian job.Results: 3 profiles were identified based on the psychological resources of the soldiers. Profiles 1, 2, and 3 differed in terms of clinical severity (PCL5). Profile 1 exhibited both the highest level of resources and the lowest clinical severity of PTSD but did not modify its resources after the intervention program when compared to profile 3. Profile 3 was characterized by the lowest level of resources, the highest clinical severity of PTSD and the highest reappropriation in all VIAs. This profile was associated with the highest rate of reintegration success 1 year after the intervention.Conclusions: This paper aims to broaden the relationship between recovery and reintegration by incorporating approaches from the field of positive psychology for soldiers with PTSD. VIA appears to be an important factor for reintegration. Our results highlight the importance of taking into account the existing needs of the patient and the optimization of the modalities of individual, collective, and institutional rehabilitation for patients suffering from PTSD in order to better understand the dynamics of the recovery process of a chronically afflicted individual

Acceptance Mindfulness-Trait as a Protective Factor for Post-Natal Depression: A Preliminary Research

(1) Background: the prevalence of postnatal depression (PND) reaches up to 20%. PND could be based on the interaction between a psychological vulnerability and chronic stress that pregnancy would activate. Vulnerability factors reflect a psychological profile mirroring mindfulness-trait (MT). A high level of MT is associated with an efficient regulation of both physiological and psychological stress, especially negative moods. Interestingly, mindfulness level can be improved by program based on mindfulness meditation. We hypothesize that MT is a protective factor for PND. We also postulate that negative moods increase during the pregnancy for women who develop a PND after delivery (2) Methods: we conducted a multicentric prospective longitudinal study including 85 women during their first trimester of their pregnancy and 72 from the childbirth to the baby’s first birthday”. At the inclusion, presence and acceptance of MT and various variables of personality and of psychological functioning were assessed. Mood evolution was monitored each month during the pregnancy and a delivery trauma risk was evaluated after delivery. PND detection was carried out at 48 h, 2, 6 and 12 months after the delivery with the Edinburgh Postnatal Depression Scale with a screening cut-off >11. (3) Results: high-acceptance MT is a protective factor for PND (OR: 0.79). Women without PND displayed less negative mood during pregnancy (p < 0.05 for Anxiety, Confusion and Anger). (4) Conclusions: these results suggest the value of deploying programs to enhance the level of mindfulness, especially in its acceptance dimension, before, during and after pregnancy, to reduce the risk of PND. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Brain innate immune system and its modulation by diet : the role of polyunsaturated fatty acids

Chapitre 11International audienceThe innate immune system of the brain is composed of microglial cells and astrocytes, which, once activated, produce proinflammatory cytokines. Proinflammatory cytokines act in the brain through specific receptors produced by brain cells and trigger behavioral modifications (sickness behavior) and cognitive and mood disorders. Aging-related neuroinflammatory processes are involved in neurodegenerative diseases. Polyunsaturated fatty acids (PUFAs) are essential nutrients provided by the diet that strongly regulate neuroinflammation and associated behavioral changes

Challenges Associated With the Civilian Reintegration of Soldiers With Chronic PTSD: A New Approach Integrating Psychological Resources and Values in Action Reappropriation

International audienceBackground: In light of the psychological changes in an individual suffering from chronic Posttraumatic Stress Disorder (PTSD), questions are being raised in order to understand and facilitate recovery and a return to work. This is particularly challenging for soldiers suffering from chronic PTSD, who are often young individuals suffering from moral conflicts. A French military rehabilitation program proposes the broadening of the relationships between recovery and reintegration by incorporating approaches from the field of positive psychology for soldiers with chronic PTSD. The aim of the study was to evaluate (i) the psychological resources which remain sustainable for these trauma exposed soldiers according to their PTSD symptoms, (ii) the dynamics of resource reappropriation after the military rehabilitation program, which focuses on values in action (VIA) as character strengths, and (iii) how these resources and their reappropriation facilitate civilian professional reintegration. Method: We conducted a prospective study with 56 trauma exposed soldiers with a clinical diagnosis of chronic PTSD. PTSD severity and psychological resources (optimism, mindfulness, well-being, motivation, self-esteem, and VIA) were assessed before and after the rehabilitation program. After the identification of resource profiles, we analyzed the impact of the program on resource levels and successful reintegration into a civilian job. Results: 3 profiles were identified based on the psychological resources of the soldiers. Profiles 1, 2, and 3 differed in terms of clinical severity (PCL5). Profile 1 exhibited both the highest level of resources and the lowest clinical severity of PTSD but did not modify its resources after the intervention program when compared to profile 3. Profile 3 was characterized by the lowest level of resources, the highest clinical severity of PTSD and the highest reappropriation in all VIAs. This profile was associated with the highest rate of reintegration success 1 year after the intervention. Conclusions: This paper aims to broaden the relationship between recovery and reintegration by incorporating approaches from the field of positive psychology for soldiers with PTSD. VIA appears to be an important factor for reintegration. Our results highlight the importance of taking into account the existing needs of the patient and the optimization of the modalities of individual, collective, and institutional rehabilitation for patients suffering from PTSD in order to better understand the dynamics of the recovery process of a chronically afflicted individual

Lesions to the ventral, but not the dorsal, medial prefrontal cortex enhance latent inhibition

The acquisition of a conditioned response to a stimulus when it is paired with a reinforcer is retarded if the stimulus has previously been repeatedly pre-exposed in the absence of the reinforcer. This effect, called latent inhibition, has previously been found to be insensitive to lesions of the medial prefrontal cortex (mPFC) in rats. Using an on-baseline conditioned emotional response procedure, which is especially sensitive to small variations in the absolute magnitude of latent inhibition, we found increased latent inhibition following excitotoxic lesions of the mPFC (Experiment 1) or the ventral mPFC alone (Experiment 2) as compared with sham-operated control rats. Lesions restricted to the dorsal mPFC, however, were without effect (Experiment 2). These results are consistent with those of experiments employing another type of interference procedure, extinction. Together, these findings suggest that when different contingencies between a stimulus and a reinforcer are established in separate learning phases, lesions to the ventral mPFC result in increased interference between first-learned and second-learned contingencies. As a consequence, retrieval of the second-learned contingency is impaired, and performance is dominated by the first-learned contingency. These findings are discussed in light of the use of latent inhibition to model cognitive deficits in schizophrenia

Lesions to the ventral, but not the dorsal, medial prefrontal cortex enhance latent inhibition

International audienceThe acquisition of a conditioned response to a stimulus when it is paired with a reinforcer is retarded if the stimulus has previously been repeatedly pre-exposed in the absence of the reinforcer. This effect, called latent inhibition, has previously been found to be insensitive to lesions of the medial prefrontal cortex (mPFC) in rats. Using an on-baseline conditioned emotional response procedure, which is especially sensitive to small variations in the absolute magnitude of latent inhibition, we found increased latent inhibition following excitotoxic lesions of the mPFC (Experiment 1) or the ventral mPFC alone (Experiment 2) as compared with sham-operated control rats. Lesions restricted to the dorsal mPFC, however, were without effect (Experiment 2). These results are consistent with those of experiments employing another type of interference procedure, extinction. Together, these findings suggest that when different contingencies between a stimulus and a reinforcer are established in separate learning phases, lesions to the ventral mPFC result in increased interference between first-learned and second-learned contingencies. As a consequence, retrieval of the second-learned contingency is impaired, and performance is dominated by the first-learned contingency. These findings are discussed in light of the use of latent inhibition to model cognitive deficits in schizophrenia

Neurological Soft Signs and Post-Traumatic Stress Disorder: A Biomarker of Severity?

International audienceBackground: The psychophysiological changes for individual suffering from chronic post-traumatic stress disorder (PTSD) raise to the questions of how facilitate recovery and return to work. Negative alterations in neuro-cognition remain a complaint for patients and participate to long-term functional impairments. Neurological soft signs (NSSs) appear as a candidate for better understanding these complaints. They have been reported in several mental disorders. They are found in several behavioral and/or neurocognitive disorders and are taken into account by psychiatric rehabilitation programs to support recovery. As few studies evaluate NSSs in PTSD, our exploratory study aims to assess NSSs in chronic PTSD and their relationships with PTSD severity.Method: Twenty-two patients with a clinical diagnosis of chronic PTSD were evaluated in terms of PTSD severity (post-traumatic checklist scale, PCL5), NSSs (NSSs psychomotor skills scale, PASS), and well-being upon arrival to the hospital and compared with 15 healthy subjects. Statistical non-parametric analyses assessed the relationships between these variables.Results: PTSD subjects exhibited higher NSSs compared with healthy subjects. NSSs were positively associated with PTSD severity, with negative alterations in cognition and mood, and with impairment in well-being. They were higher in women compared with men. No impact of age was found. Three groups were identified based on the severity of the PTSD. Severe PTSD exhibited NSSs characterized by motor integration alterations.Conclusions: This pilot study suggests that NSSs might be a biomarker of PTSD severity. This proof of concept highlights the need for further research for better evaluating the clinical neuro-functional impairment. This will be helping for defining neurological remediation for promoting PTSD recovery

Implémentation d’un programme de PREvention primaire du trouble de Stress post-traumatique chez les Professionnels des Armées (PREPAR) : essai randomisé en groupe parallèle.

International audienceBACKGROUND: Post-traumatic stress disorder (PTSD) is a psychiatric disorder that can manifest after a traumatic event, in which the individual perceives a threat to his or her life, or that of others. Its estimated prevalence in the European population is 0.7–1.9%. According to the ‘dose-response’ model, individuals who are most exposed to traumatic events are most at risk of developing the disorder. Hence, it is unsurprising that studies have observed a higher prevalence among the military population, ranging from 10–18%, or even up to 45%. The overall goal of this project is to evaluate primary prevention actions that can strengthen the resilience of at-risk professionals, notably military personnel, in the short term, with the medium to long-term aim of preventing the occurrence of PTSD, and improving the patient’s prognosis. OBJECTIVE: The project’s objectives are: (i) to design a primary prevention program for PTSD, tailored to the studied military population, and compatible with operational constraints; and (ii) to implement/ validate the PREPAR program in the short term with operational personnel belonging to the French Mountain Infantry Brigade (Brigade d’Infanterie de Montagne). METHODS: This is a single-center, prospective, randomized, parallel-group controlled cohort study. The cohort of 116 participants is divided into two groups: the non-intervention (NI) group receives no training, and the intervention group (I) follows a dedicated prevention program. Each participant is evaluated four times (at inclusion, +4 months, +6 months, and +12 months). Members of the I group attend eight workshops, making up the prevention program, and two debriefing and practice reinforcement workshops. All visits and workshops are conducted at the Brigade’s premises. During each visit, participants complete several psychosocial questionnaires (which take 15–80 minutes to complete, depending on the visit). Samples (a 30 ml blood sample, and three 5 ml saliva samples) are collected on three occasions: at inclusion, +4 months, and +12 months. Emotional reactivity (electrocardiogram and electrodermal activity) is measured before, during and after the classic and the emotional Stroop task, using surface electrodes placed on the last phalanx of two fingers, and the thorax. RESULTS: This a protocol paper, therefore there is no result presented CONCLUSIONS: The study adopts an integrative approach to the processes that play a role in the risk of developing PTSD. Our biopsychosocial perspective makes it possible to target levers related to factors specific to the individual (at physiological and psychological levels), and contextual and social factors (related to the professional environment). The following dimensions are addressed: (i) biophysiology (by studying the key markers of the neurobiological stress response, wear and tear, and vulnerability phenomena, and by reinforcing the flexibility of the autonomic nervous system), (ii) psychology (by facilitating and measuring the development of flexible coping strategies to deal with stress, and evaluating the moderating role of the individual’s sense of duty in the development of PTSD) and (iii) social (by facilitating community strategies aimed at reducing stigmatization and supporting the use of care by professionals in difficulty, in the institutional context). CLINICALTRIAL Trial Registration: ClinicalTrials.gov NCT05094531.Introduction : Le Trouble de Stress Post-Traumatique (TSPT) est un trouble psychiatrique qui se manifeste suite au vécu d’un évènement traumatique, dans lequel l’individu a perçu une mise en danger de sa vie ou de celle d’autrui. Sa prévalence en population Européenne s’établit entre 0,7% et 1,9%. Selon le modèle « dose-réponse », les individus les plus exposés à des évènements traumatiques (ET) sont ceux qui sont le plus à risques de développer ce trouble. C’est pourquoi il n’est pas surprenant d’observer en population militaire une prévalence plus importante de ce trouble, allant de 10% à 18% voire 45%, suivant les études. Le but général dans lequel s’inscrit ce projet est celui d’explorer des pistes d’actions de prévention primaire pour renforcer à court terme les capacités de résilience chez des professionnels à risques, que sont les militaires, afin de prévenir à moyen et long terme la survenue du TSPT et d’en améliorer le pronostic. Les objectifs du projet sont (i) de concevoir un programme de prévention primaire du TSPT spécifique de la population militaire étudiée et compatible avec les contraintes opérationnelles des militaires de terrain, (ii) de l’implémenter / le valider auprès des opérationnels de la Brigade d’Infanterie de Montagne (BIM) en ciblant le court terme.Méthode : Il s’agit d’une étude monocentrique analytique de cohorte prospective, randomisée, contrôlée en groupes parallèles. La cohorte de 116 participants est scindée en deux groupes : le groupe qui ne suit pas de formation : groupe non intervention (NI) et le groupe qui suit le programme de prévention : groupe intervention (I). Chaque participant inclus réalise 4 visites (inclusion, +4 mois, + 6mois et + 12mois). Les sujets du groupe intervention doivent de plus suivre 8 ateliers du programme de prévention et 2 ateliers de débriefing et renforcement de la pratique. L’ensemble des visites et ateliers sont réalisés au sein de la BIM. Lors de chaque visite, les sujets doivent compléter des questionnaires psychosociaux (dont le temps de remplissage est compris entre 15 à 80 minutes, selon les visites). Des prélèvements (prise de sang 30 ml et prélèvements salivaires de 5 ml) sont réalisés à trois reprises : visite d’inclusion, visite +4 mois et visite +12 mois. Un enregistrement de la réactivité émotionnelle (variabilité cardiaque et sudation cutanée) est réalisé, avant, pendant et au décours d’un test de Stroop classique et émotionnel, à l’aide d’électrodes cutanées au niveau de deux doigts et au niveau du thorax.Discussion : Notre démarche consiste à adopter une lecture intégrative des processus en jeu dans le risque de développement du TSPT selon une approche biopsychosociale permettant de cibler à la fois des leviers d’intervention relevant de facteurs propres à l’individu sur le plan physiologique et psychologique ainsi que de facteurs contextuels et sociaux relatifs au cadre professionnel. Les dimensions abordées sont : (i) la biophysiologie (en intégrant l’étude des biomarqueurs clefs de la réponse neurobiologique de stress, des phénomènes d’usure et de vulnérabilité et en renforçant la flexibilité du système nerveux autonome), (ii) la psychologie (en facilitant et mesurant le développement de la flexibilité des stratégies de coping pour faire face au stress ainsi qu’en évaluant le rôle modérateur du sens porté à la mission de travail dans le développement du TSPT) et (iii) le social (en facilitant les stratégies communautaires visant la réduction de la stigmatisation et facilitant le recours aux soins des professionnels en difficulté dans le contexte institutionnel)

Subsurface Confinement: Evidence from Submariners of the Benefits of Mindfulness

International audienceObjectivesThe subsurface ballistic missile nuclear submarine (SSBN) is an extreme professional environment in which personnel are both isolated and confined during patrols, which can last longer than 2 months. This environment is known to degrade submariners’ mood and cognition.MethodsThis exploratory, empirical study followed a cohort of 24 volunteer submariners. Dispositional mindfulness was assessed with the Freiburg Mindfulness Inventory, in order to identify two groups (mindful and non-mindful) and compare change in emotional state, interoception, and health behaviors during the patrol.ResultsOverall, psychological health deteriorated during the patrol. However, mindful submariners demonstrated better psychological adaptation and interoception than the non-mindful group. This was associated with better subjective health behaviors (sleeping and eating).ConclusionsDispositional mindfulness appears to protect against the negative effects of long-term containment in a professional environment, such as a submarine patrol. Our work highlights that mindfulness may help individuals to cope with stress in such situations. Developing mindfulness could also be an important preventive healthcare measure during quarantine imposed by the outbreak of a serious infectious disease