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The Evil Inside : A Systematic Review of Structural Differences in PsychopathyRehn Åstrand, Diana, Vedin, Julia January 2023 (has links)
The purpose of this systematic review was to characterize further the structural differences in the prefrontal cortex, limbic and paralimbic regions and amygdala alone in psychopaths. Psychopathy is a multifaceted personality disorder characterized by interpersonal and affective traits like lack of empathy, guilt or remorse, shallow affect, and carelessness, as well as behavioral traits such as impulsivity, and poor behavioral control. In recent years, the interest in the neuroanatomical differences in psychopaths has grown. This review aims to understand the prefrontal cortex, limbic and paralimbic areas, and how these regions differ between psychopathic patients and healthy controls. By systematically screening articles that used magnetic resonance imaging (MRI) and voxel based morphometry (VBM) the studies in this review examined people with psychopathic traits. To assess for psychopathy, the most used assessment tool, the Psychopathy Checklist-Revised (PCL-R) was used. Results show that the higher the PCL-R scores of the offenders, the less gray matter volume was found in the superior parts of the prefrontal cortex, limbic and paralimbic areas. Additionally, amygdala deficits in individuals with psychopathy were found. This systematic review may benefit in the way that if we increase our understanding of psychopathy and pave the way forthe creation of effective psychopathic treatments it could prevent future acts of violence. The link between a structural brain anomaly and psychopathy may have a profound clinical, legal, and scientific impact. A psychopathy diagnosis may serve as a precursor to severe societal violence.
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Mécanismes cérébraux impliqués dans le trouble de stress post-traumatique et dans sa rémission symptomatique / Neural mechanisms involved in posttraumatic stress disorder and in its recoveryBoukezzi, Sarah 20 February 2017 (has links)
L’objectif de cette thèse a été de comprendre les mécanismes cérébraux associés aux symptômes du trouble de stress post-traumatique (TSPT), ainsi que les mécanismes cérébraux modulés par la disparition des symptômes, en utilisant la thérapie de désensibilisation et de retraitement de l’information par les mouvements oculaires (Thérapie EMDR). Cette thérapie associe rappel du traumatisme et stimulations bilatérales alternées (SBA). Premièrement, en utilisant l’IRM fonctionnelle (IRMf), nous avons mis en évidence une altération de l’activité fonctionnelle du système de récompense dans le TSPT, correspondant à une mobilisation déséquilibrée des processus motivationnels cognitifs et hédoniques (étude 1). Deuxièmement, par l’intermédiaire d’une étude en IRMf au repos, nous avons montré que les patients présentent des altérations de connectivité fonctionnelle entre un réseau neuronal impliqué dans les processus mnésiques et émotionnels, et un réseau neuronal impliqué dans les processus attentionnels (étude 2). Troisièmement, nous avons montré que les structures initialement altérées par la pathologie évoluent après rémission symptomatique, suggérant un rétablissement des altérations neuronales induites par le stress chronique (étude 3). Enfin, nous avons montré que les SBA employées dans la thérapie EMDR facilitent l’extinction de la peur ainsi que la récupération de cette extinction au sein d’un groupe de volontaires sains (étude 4). Ainsi, ces travaux offrent de nouvelles perspectives en termes de modélisation de la pathologie, et offre de nouvelles pistes de réflexion quant à la prise en charge thérapeutique de ce trouble. / Posttraumatic Stress Disorder (PTSD) is a debilitating psychiatric disorder that arises in the aftermath of a traumatic event. To date, the Eye Movement Desensitization and Reprocessing therapy (EMDR) therapy has shown to be the most efficient therapy for the treatment of PTSD. The aim of this thesis was therefore to understand neural mechanisms underlying PTSD and its recovery. To do so, we conducted four studies. In a first study, we showed alterations in the reward circuit activity in PTSD patients, which may underlie an imbalance mobilization of cognitive and hedonic motivational processes, possibly contributing to emotional numbing in PTSD (study 1). Following this, an altered resting state functional connectivity between a network associated with attentional processes and another associated with emotional and memory processes was also found, suggesting an atypical emotional regulation and attention processing (study 2). A third study showed changes of grey matter density in regions involved in emotional regulation after symptoms remission by EMDR therapy. Finally, we were also able to replicate, in PTSD patients, the fear extinction and fear extinction recall facilitation by bilateral alternating stimulations (BAS) a major component of EMDR therapy, previously demonstrated in animal studies. Taken together, the present findings of these studies contribute to enlarge our knowledge, opening new ways of thinking the actual model of explaining the PTSD. More importantly, we believe that our findings may contribute to improve therapeutic strategies to significantly ameliorate the life of these patients.
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