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

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