Les troubles exécutifs de la maladie de Parkinson sont invalidants et sans solution thérapeutique satisfaisante. La raison est liée au fait que les fonctions exécutives sont difficiles à appréhender, tant au niveau de leur modélisation cognitive qu'anatomo-fonctionnelle ou neurochimique. Ici, nous nous appuyons sur des avancées théoriques et méthodologiques récentes pour revisiter ces troubles exécutifs. Nous nous intéressons à une fonction, récemment mise en évidence, destinée à verrouiller par anticipation le déclenchement de toute action en situation d'incertitude : le contrôle proactif de l'inhibition non sélective de l'action. Notre hypothèse directrice est que son dysfonctionnement est susceptible de générer une grande variété de troubles exécutifs. Nous avons : 1) recherché les liens entre marqueurs cliniques et troubles du contrôle proactif ; 2) identifié les dysfonctionnements cérébraux associés au moyen de méthodes électroencéphalographiques innovantes combinées à l'enregistrement des effets de la stimulation du noyau sous-thalamique ; et 3) sondé l'origine neurochimique de cette fonction. Nos résultats suggèrent qu'un dysfonctionnement de l'inhibition proactive n'engendre pas uniquement des troubles impulsifs mais explique également des comportements hypo-productifs comme l'akinésie. Ils indiquent que ces troubles ne sont pas d'origine dopaminergique et qu'ils sont liés au dysfonctionnement de l'activité du cortex frontal médian et du noyau sous-thalamique. Ces travaux ouvrent la voie à de nouvelles perspectives thérapeutiques pour la maladie de Parkinson et à une meilleure appréhension de la clinique d'autres pathologies / Executive impairments in Parkinson’s disease are debilitating and have no satisfying therapeutic option. This is partly due to the fact that executive functions are difficult to investigate from cognitive, neuro-functional and neurochemical standpoints. Here, we build on recent theoretical and methodological improvements to revisit executive impairments. We are interested in a function that consists in locking in advance movement initiation mechanisms in the face of uncertainty: proactive control of non-selective inhibition of action. Our leading hypothesis is that dysfunction of proactive inhibitory control could generate widespread and heterogeneous executive impairments. We thus: 1) tried to relate clinical markers of the disease to behavioral indexes of proactive control impairment; 2) identified the associated cerebral dysfunctions by means of advanced electroencephalographic methods and manipulation of deep brain stimulation of the subthalamic nucleus; and 3) investigated the neurochemical origin of this function. Our results suggest that impulsivity is not the only outcome of inhibitory impairment. Disorder of proactive inhibitory control may also account for hypo-productive behaviors such as akinesia. Results also indicate that this mechanism is of non-dopaminergic origin and relies on medial frontal and subthalamic activity. This work opens the way for new therapeutic approaches for Parkinson’s disease as well as a better understanding of clinical symptoms observed in others diseases

L'impulsivité, un trait multidimensionnel, détermine la sévérité d'affections comportant des désordres compulsifs (syndrome de Gilles de la Tourette, maladie de Parkinson, troubles obsessionnels compulsifs), mais la nature de la relation impulsivité / compulsivité reste méconnue. L'intérêt du présent travail est d'identifier les substrats neurobiologiques de la balance impulsivité / compulsivité, dans une approche transnosographique, en s'aidant au plan préclinique, de manipulations causales et au plan clinique, d'une approche corrélationnelle. Ainsi, nous démontrons pour la première fois en dehors du champ de l'addiction, non seulement que l'impulsivité motrice, endophénotype de vulnérabilité à la compulsivité, prédit, sous l'influence de la transmission noradrénergique, la transition vers la compulsivité, mais aussi que (dans le modèle de la maladie de Parkinson) la dénervation de la voie nigrostriée et les traitements substitutifs dopaminergiques amplifient l'état impulsif. D'où l'interaction complexe entre le trait impulsif, les traitements et le processus dégénératif. Enfin, nous démontrons le bénéfice thérapeutique de la stimulation de la portion antérieure du pallidum interne dans les formes sévères de tics et suggérons dans un modèle préclinique d'une grande valeur heuristique, que le trait impulsif prédit l'efficacité de la stimulation du core du noyau accumbens. Nos résultats démontrent l'intérêt de mieux caractériser le trait impulsif des patients présentant des désordres compulsifs (syndrome de Gilles de la Tourette, maladie de Parkinson) et ouvrent ainsi de nouvelles perspectives thérapeutiques, tant pour la prévention de la transition de l'impulsivité à la compulsivité, que dans le traitement de ceux-ci. / Impulsivity, a multidimensional trait, determines the severity of compulsive disorders (Tourette's syndrome, Parkinson's disease, obsessive compulsive disorders), but the impulsive / compulsive relation remains unclear. The aim of this work is to identify the neurobiological substrates of impulsive / compulsive balance, using causal manipulations in rats and correlational studies in patients. The results demonstrate - for the first time beside the field of addiction - that, not only high impulsive trait is a transnosological endophenotype of increased vulnerability to develop compulsive disorders, but also that the transition from impulsivity toward compulsivity depends upon the noradrenergic transmission. Furthermore, we also show that, in a Parkinson's disease preclinical model, both the nigrostriatal denervation and dopaminergic treatments increase impulsive state, thereby indicating the contribution of a complex interaction between impulsive trait, medications and neurodegenerative process to the impulsive/compulsive balance. Finally, we show the therapeutic benefit of anterior globus pallidus interna in severe forms of tics and suggest in a preclinical model, with great heuristic value, that impulsive trait predicts the efficacy of nucleus accumbens core stimulation. Together, our results demonstrate the need to address the impulsive/compulsive balance in compulsive disorders and show promise for developing new pathophysiological-based therapeutic strategies that will treat both impulsivity and compulsivity.

L’impulsivité décisionnelle est une des multiples dimensions de l’impulsivité. Elle est définie comme la préférence d’une petite récompense immédiate à une grande récompense différée, et dérive du fait que la valeur que l’on attribue à une récompense diminue avec le temps. Quand la dévaluation temporelle est excessive, l’impulsivité de choix devient un symptôme présent dans de nombreuses pathologies. Le striatum, structure cérébrale profonde composée de trois sous-territoires, le noyau caudé, le striatum ventral et le putamen, est un élément clé dans le traitement de l’impulsivité décisionnelle. En effet, il constitue la principale cible de la dopamine, connue pour être un modulateur de l’impulsivité. En lien avec le cortex, le striatum antérieur est impliqué dans les processus de prise de décision, de motivation liée à la récompense, et de sélection de l’action. Nous avons étudié le rôle spécifique des territoires du striatum dans l’impulsivité de choix chez le singe réalisant une tâche de dévaluation temporelle. En utilisant une approche comportementale et d’imagerie, nous avons montré que le noyau caudé était impliqué dans l’impulsivité de choix induite par le Pramipexole, un agoniste dopaminergique des récepteurs D2/3. Dans une seconde étude, nous avons montré que le Méthylphénidate, un inhibiteur de recapture de la dopamine utilisé comme traitement du trouble du déficit attentionnel/hyperactivité, diminuait l’impulsivité décisionnelle en passant par une action sur le striatum ventral. En résumé, ces résultats confirment le rôle de la dopamine dans l’impulsivité décisionnelle et montrent les rôles spécifiques du noyau caudé et du striatum ventral dans les processus décisionnels liés à la dévaluation temporelle / Temporal discounting is the process by which future rewards are subjectively devalued by the decision maker. Impulsive choices, defined as the tendency to prefer small immediate rewards over larger but delayed ones, derive from a high temporal discounting. This particular dimension of impulsivity is a trait of personality, but also a symptom in many neuropsychiatric disorders. It has been shown many times that impulsive choices can be modulated by dopaminergic agents. The dopamine targets the striatum, a cerebral structure linked to cortex, subdivided into three territories – the Ventral Striatum (VS), the Caudate Nucleus (CdN) and the Putamen - and involved in motivation, goal directed behaviors, decision making and action selection. All these functions are involved in impulsive behaviors, although the specific role of each territory in impulsivity remains unknown. Here, using pharmacologic and imaging approaches, we aimed to study the role of the anterior striatum in impulsive choices using the delay discounting task in non-human primates. First, we showed that the CdN supports impulsive choices triggered by Pramipexole, a D2/3 agonist suspected to produce impulsive control disorders. In a second study, we used Methylphenidate, a blocker of dopamine transporter used in attention deficit hyperactivity disorder, and we demonstrated that the VS supports Methylphenidate therapeutic effects on impulsive choices expressed in temporal discounting task. Together, our results show that dopaminergic modulation plays a specific role on the CdN and the VS in the processes of impulsive choices, and suggest a dual action between ventral and dorsal striatal territories

Human decision making is closely related to reward processing because many decisions rely to a certain degree on the evaluation of different outcome values. Reward-based decisions can be health-related, for example if someone has to compare the outcome value of the instant reward of smoking a cigarette to that of the long term goal of keeping well and fit. Such comparisons do not only rely on the nominal value of the alternatives but also on devaluation of rewards over time. The value of being healthy at older age might outweigh the value of smoking a cigarette but since the payoff of the health-outcome will be delayed, humans tend to decrease the value of this option. Therefore in this example one might choose the immediate reward of smoking a cigarette. The proclivity to devaluate the value of rewards over time has been widely investigated with experimental intertemporal choice tasks, in which subjects have to choose between smaller sooner rewards and larger later rewards. A stronger individual devaluation proclivity (i.e. discounting rate) has been reported to be related to addiction. Research in neuroeconomics has suggested the competing neurobehavioural decision systems (CNDS) theory, proposing that an imbalance between an executive (cortical prefrontal brain areas) and an impulsive (i.e. subcortical areas, such as ventral striatum (VS), amygdala) system in the brain leads to steeper discounting and a higher risk for addiction. Additionally, temporal discounting has been proposed as a transdisease process, i.e., “a process that occurs across a range of disorders, making findings from one disorder relevant to other disorders” (Bickel, Jarmolowicz, Mueller, Koffarnus, & Gatchalian, 2012, Abstract). Thus, the CNDS theory and temporal discounting might also have implications for other health-related behaviour than substance use. So far many factors have been shown to be associated with higher discount rates: for instance, adolescent age, lower intelligence and nicotine dependence. Further, it has been shown that adolescents are at highest risk to start smoking. On the other hand a higher education level has been shown to be associated to lower rates of smoking. Thus, it seems likely that a higher discount rate might be one reason why adolescents experiment with smoking, why lower education is associated to nicotine addiction and why dependent smokers are not successful in smoking cessation. But relatively little is known about the neural processes behind these variables, which could be also seen as exemplary risk- and protective factors regarding addiction. The 3 studies of the thesis at hand were conducted to extend the knowledge about neural processes associated to age, intelligence and smoking in their relation to intertemporal choice. The task was chosen because of its relevance for addiction and a variety of health-related behaviour. The first study was conducted to explore the neural correlates of age related differences between adolescents at age 14 and young adults during intertemporal choices. Additionally, the roles of discounting and choice consistency were investigated. Although adoles-cents discounted delayed rewards more steeply than adults, neural processing of reward value did not differ between groups, when controlling reward values for the individual discount rates. However, a higher discount rate was related to a lower responsivity in the ventral striatum to delayed rewards, independent of age. Concerning decision making, adolescents exhib-ited a lower consistency of choices and less brain activity in a parietal network than adults (i.e. posterior and inferior parietal regions). Thus, reward value processing might be more sensitive to the discount rate than to chronological age. Lower consistency of intertemporal choices might indicate ongoing maturation of parietal brain areas from adolescence to young adulthood. The second study was conducted to reveal the associations between neural processes of decision making and intelligence in adolescents. The results of study 2 revealed networks in the adolescent brain where brain activity was related to crystallised intelligence as well as to intertemporal choice behaviour. Specifically, during decision processing higher crystallised intelligence as well as more consistent decisions were associated with higher brain activity in the posterior parietal cortex. Processing of delayed rewards was also related to crystallised intelligence, i.e. more intelligent adolescents showed higher brain activation in the anterior cingulate cortex (ACC) and the inferior frontal gyrus (IFG), which was in turn related to a lower discount rate. Additionally, associations between the parental education level and crys-tallised intelligence of the adolescent participants of the study and their discount rate were found, indicating that parental education as an environmental factor could be related to a low-er risk for addiction. This protective effect might be mediated by the offspring’s crystallised intelligence and discount rate which are both related to brain activity in parts of the same brain networks (i.e. the IFG). The third study was done to investigate neural processes of intertemporal decisions in smokers and non-smokers. To test whether the effects of smoking on the discount rate are due to chronic or acute nicotine intake, non-smokers were additionally assessed under acute nico-tine administration. Study 3 revealed that the effects of nicotine on intertemporal choice behaviour were related to chronic intake of nicotine in smokers rather than to acute nicotine ad-ministration in non-smokers. Regarding the neural processes, smokers compared to non-smokers showed lower brain activity in the posterior parietal cortex. Comparable but weaker effects were found under acute nicotine in non-smokers. Although acute nicotine administra-tion altered neural processes, behavioural changes might only occur after repeated nicotine intake. However, the study did not preclude that the differences are predrug characteristics. Altogether the studies revealed overlapping neural correlates of intertemporal choices which are related to the individual age, the discount rate, the choice consistency, the individual intelligence as well as acute and chronic nicotine intake. This might provide an integrative view on how inter-individual differences and behaviour during intertemporal choices are based on common neural correlates which in turn might have implications for the development and the maintenance of addiction. Specifically, hyposensitivity towards delayed rewards in the adolescent ventral striatum, which has also been found in smokers compared to non-smokers, is associated with higher discount rates and higher risk for smoking initiation. In contrast, higher activation in the IFG and the ACC in more intelligent individuals during reward value processing might enhance behavioural inhibition and control and, hence, might prevent nicotine addiction. In line with the CNDS theory responsivity in subcortical brain areas (i.e. impulsive system), such as the VS was related to the risk factor of adolescent age, whereas activity in cortical areas (IFG and ACC) was related to the protective factors of high-er crystallised intelligence. Since there was only one study beside the studies of the current thesis reporting results regarding consistency, one can only speculate about implications for health-related behaviour, such as addiction. Consistency might play a role, especially for cessation success. Thus, the findings that adolescents as well as less intelligent individuals were less consistent might point to a higher risk for maintenance of nicotine addiction. The higher brain activity in a fronto-parietal network, which has been shown in studies 1 and 2 in adults as well as in more intelligent adolescents, was related to higher consistency of choices in both studies. Thus, the finding might be a possible neural correlate for the association between the risk factor of ado-lescent age, the protective factor of higher crystallised intelligence, and more consistent deci-sion making. In conclusion the findings of the current thesis contribute to a better understanding of how inter-individual differences and environmental factors might be accompanied by neural processes which in turn might be related to individual development of addiction. Further the results might extend the CNDS theory regarding neural correlates of exemplary risk and pro-tective factors regarding adolescents’ health behaviour and smoking in adults.

Borderline Personality Disorder (BPD), as defined by the DSM-IV-TR (APA, 2000), is a multifaceted mental illness characterized by pervasive instability of interpersonal relationships, self-image, affect and behavior. Despite a growing consensus that the etiological basis of BPD stems from a combination of biological vulnerability and an early developmental history characterized by invalidation, abuse and/or neglect (e.g., Clarkin, Marziali, & Munroe-Blum, 1991; Linehan, 1993), the reasons for the diversity of troubling symptoms (e.g., self-injury, suicidality, mood reactivity, relationship difficulties) remain unclear. Psychopathology theorists differ in their conceptualization of the fundamental problems (e.g., impulsivity vs. identity disturbance vs. emotion dysregulation) underlying BPD and further research is needed to clarify which features are central to the maintenance of the difficulties associated with the disorder. In the current research, the some of the tenets of Linehan’s (1993) biosocial theory of BPD and the core constructs implicated in her conceptualization of the disorder were explored empirically in several samples of undergraduate university students. According to the biosocial theory, difficulties regulating emotions represent the core pathology in the disorder and contribute causally to the development and expression of all other BPD features. The emotional dysregulation is proposed to emerge from transactional interactions between individuals with biological vulnerabilities (i.e., a highly arousable temperament, sensitive to both positive and negative emotional stimuli) and specific environmental influences (i.e., a childhood environment that invalidates their emotional experience). The theory asserts that the dysregulation affects all aspects of emotional responding, resulting in (i) heightened emotional sensitivity, (ii) intense and more frequent responses to emotional stimuli, and (iii) slow return to emotional baseline. Furthermore, Linehan proposed that individuals with BPD lack clarity with respect to their emotions, have difficulties tolerating intense affect, and engage in maladaptive and inadequate emotion modulation strategies. As a result of their dysfunctional response patterns during emotionally challenging events , individuals with BPD fail to learn how to solve the problems contributing to these emotional reactions. In accordance with this theory, a number of hypotheses were tested. First, it was hypothesized that the interaction between temperamental sensitivity and an adverse childhood environment would predict BPD features over and above that predicted by either construct independently. Second, it was hypothesized that BPD traits would be predicted by high levels of emotional dysregulation (affect lability), problems across different aspects of emotional experience (e.g., intensity, awareness, clarity), and deficits in emotion regulation skills (e.g., poor distress tolerance, self-soothing). Based on the initial findings of the research, a series of competing hypotheses were tested that addressed the nature of the emotional, cognitive and motivational mechanisms that may underlie maladaptive behavior in BPD more directly. Prior to testing these hypotheses, it was important to select a set of measures that would best represent these constructs within an undergraduate population. The purpose of Studies 1a and 1b (N = 147 and N = 56, respectively) was to determine the reliability and validity of a series of self-report measures that assess BPD features and to select one questionnaire with high sensitivity (percentage of cases correctly identified) and high specificity (percentage of noncases correctly identified) as a screener for BPD within undergraduate students by comparing the results of the questionnaires against a “gold standard” criterion diagnosis of BPD (as assessed by two semi-structured interviews: DIB-R and IPDE-I). The second goal of these studies was to conduct a preliminary exploratory analysis of the association of scores on the BPD measures and constructs that have been hypothesized to be relevant to the development and maintenance of BPD symptoms (e.g., “Big Five” personality factors, emotional experience, impulsivity). Overall, the findings of Studies 1a and 1b indicated that screening for BPD in an undergraduate population is feasible and there are several questionnaires that may help in the identification of participants for future studies. Specifically, the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD; Zanarini et al., 2003), International Personality Disorder Examination DSM-IV Screening Questionnaire (IPDE-S; Loranger, 1999) and Borderline Personality Questionnaire (BPQ; Poreh et al., 2006) were all found to be internally consistent and valid screening measures. Furthermore, the results of correlation and regression analyses between dimensions of the “Big Five” and scores on the BPD measures were consistent with previous findings in the literature that BPD is associated with higher scores on neuroticism, lower scores on agreeableness, and to a lesser degree, lower scores on conscientiousness and extraversion. The similarity in results between the current and past studies suggested that individuals in the present samples showed characteristics consistent with that seen in both clinical and nonclinical populations with BPD traits. The results also provided support for the notion that individuals with BPD have a lower threshold (i.e., greater sensitivity) for both sensory and affective stimuli, as well as higher amplitude of emotional response (i.e., greater reactivity) to such stimuli. Furthermore, the findings suggested that those with BPD traits may lack understanding of their emotional state, may be unable to effectively regulate their emotional state, and that their impulsive behavior may be driven by negative affect. The purpose of Study 2 (N = 225) was to test some of the specific tenets of Linehan’s (1993) biosocial theory. The results suggested that BPD traits are associated with numerous dimensions of temperament [e.g., higher levels of negative affect; lower levels of positive affect; lower levels of effortful control; low sensory threshold (i.e., greater sensitivity) for both sensory and affective stimuli; ease of excitation (i.e., greater reactivity to sensory and affective stimuli)] and childhood environment (e.g., authoritarian parenting style, invalidating parenting, neglect, abuse). An examination of the interactions between dimensions of temperament and childhood environment suggested that interactions between (i) ease of excitation (greater reactivity to sensory and affective stimuli) and environment and (ii) trait negative affect and environment, predicted BPD symptoms over and above the temperament and environment variables alone. The results also suggested that a number of other factors are associated with BPD symptoms, including: increased attention to (or absorption in) emotional states, poor emotional clarity, affect lability (particularly anger), poor distress tolerance, and negative urgency (impulsive behavior in the context of negative affect). The association between BPD symptoms and difficulties identifying feelings seemed to be mediated by affect lability and negative urgency. Self-soothing and self-attacking did not predict BPD traits over and above the other variables. Wagner and Linehan (1999) also proposed that the intense emotions (and emotional dysregulation) experienced by those with BPD interferes with cognitive functioning and effective problem solving, resulting in poor decisions and the observed harmful behaviors. Other researchers have suggested that the repetitive, self-damaging behavior occurring in the context of BPD may reflect impairments in planning and failure to consider future consequences (e.g., van Reekum et al., 1994). Proponents of this view suggest that individuals with BPD show greater intensity and lability in their emotional response to their environment because they are unable to inhibit or moderate their emotional urges (i.e., impulsivity is at the core of the disorder). The purpose of Study 3 (N = 220) was to characterize decision making in an undergraduate sample of individuals with BPD traits and to ascertain the relative contribution of individual differences in the following areas to any deficits identified in decision making: emotional experience (e.g., increased affective reactivity or lability); reinforcement sensitivity (e.g., sensitivity to reward and/or punishment); impulsivity; executive functioning (measured by an analogue version of the Wisconsin Card Sorting Test); and reversal learning. Decision making was assessed using modified versions of two Iowa Gambling Tasks (IGT-ABCD and IGT-EFGH; Bechara, Damasio, Damasio, & Anderson, 1994; Bechara, Tranel, & Damasio, 2000) that included reversal learning components (i.e., Turnbull et al., 2006). The results of Study 3 showed that participants in the BPD group demonstrated deficits in decision-making as measured by the IGT-ABCD but not on the IGT-EFGH. The results [interpreted in the context of reinforcement sensitivity models, the somatic marker hypothesis (Damasio, 1994) and the “frequency of gain” model e.g., Chiu et al. 2008)] suggested that decision making under uncertainty may be guided by gain-loss frequency rather than long-term outcome for individuals with BPD traits. The results failed to show consistent associations between BPD symptoms and performance on either version of the IGT. Individual differences in emotional experience, executive functioning or reversal learning did not account for the decision-making problems of the BPD group on the IGT-ABCD.

Contexte : Jusqu’à 90% des fumeurs qui tentent d’arrêter de fumer vont rechuter dans l’année suivant la date d’arrêt. L’impulsivité, au même titre que le « craving », a démontré être un bon facteur de prédiction de la rechute tabagique. Ainsi, la présente étude visait à évaluer, à l’aide de la neuroimagerie fonctionnelle, l’influence de l’impulsivité sur les mécanismes neuronaux du « craving » de la cigarette. Parmi les régions cérébrales impliquées dans le « craving » de la nicotine, les cortex préfrontal dorsolatéral, orbitofrontal et cingulaire sont d’importantes structures dans les processus de contrôle de soi. Méthodes : 31 fumeurs chroniques ont passé une session de neuroimagerie durant laquelle ils devaient regarder des images appétitives de cigarettes et des images neutres. Ils ont ensuite dû inscrire le « craving » ressenti à la vue des images et répondre à un questionnaire portant sur les traits de personnalité de l’impulsivité (BIS-11). Résultats : Tel qu’attendu, le score d’impulsivité était positivement corrélé au « craving » rapporté par les participants à la vue d’images de cigarettes. Au niveau cérébral, plus les fumeurs présentaient de forts traits d’impulsivité, moins grande était l’activité du cortex cingulaire postérieur (CCP) durant le « craving ». Enfin, l’activité du CCP présentait une connectivité fonctionnelle négative avec l’insula, le cortex préfrontal dorsolatéral et le cortex cingulaire antérieur. Conclusions : Comme le CCP est le siège des processus de mentalisation et de référence à soi, nous suggérons que plus les fumeurs étaient impulsifs, moins ils prenaient conscience de leur état et moins ils en exerçaient un contrôle, donc plus ils ressentaient de forts « cravings ». En poussant plus loin, nos résultats mettent l’accent sur l’aspect identitaire (le soi, les mémoires autobiographiques) et l’aspect d’introspection en toxicomanie : deux avenues à explorer. / Background: 90% of cigarette smokers attempting to quit smoking relapse by one-year following their quit date. Impulsivity, as well as cue-induced cravings, have been shown to be good predictors of relapse for tobacco smoking; however, no study to date has examined their interaction and its neural substrates. The goal of this study was to determine the neural influence of trait impulsivity during functional imaging of cue-induced cigarette cravings. Among the brain regions involved in nicotine craving, the dorsolateral prefrontal cortex, the orbitofrontal as well as the cingulate cortex all play a significant role in self-control processes. Methods: Thirty-one chronic smokers passively viewed appetitive smoking-related and neutral images while being scanned. Participants also reported their level of craving and completed the BIS-11, a measure of trait impulsivity. Results: As hypothesized, we observed a significant positive relationship between impulsivity scores and reported craving. Impulsivity scores were negatively correlated with activity in the posterior cingulate cortex (PCC). The insula, dorsal anterior cingulate cortex and dorsolateral prefrontal cortex presented a negative connectivity with the PCC. Conclusions: Given that the PCC is involved in mentalization and self-relevant processing, it is possible that greater trait impulsivity in smokers is associated to a lower tendency to understand and use one’s mental and physical state to guide behavior. This may weaken their capacity for self-control and consequently, promotes more automatic and stronger cue-elicited smoking urges. Furthermore, our results highlight the important but undervalued role of identity (the self and autobiographic memories) and mindfulness in addiction.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

L’Urgence négative est un trait caractéristique du trouble de personnalité limite. Cependant ce modèle des traits ne permet pas d’expliquer les variétés des formes d’expression ni le niveau de sévérité de gestes impulsifs, qu’ils soient dirigés contre soi ou contre autrui. L’intégration du modèle des relations d’objet à celui des traits offre une meilleure compréhension de cette variabilité. Dans la théorie des relations d’objet, la diffusion de l’identité est spécifique aux organisations limites de la personnalité. Elle est caractérisée par un manque d’intégration des représentations de soi et d’autrui à cause d’une séparation excessive des affects positifs et négatifs investis dans les images de soi et d’autrui. Elle est associée à un manque d’intégration des structures psychiques du Moi et du Surmoi. Le niveau de l’intégration de l’identité agirait en modulant la relation en un trait d’urgence négative élevé et l’expression des gestes impulsifs. Cette étude, réalisée auprès d’étudiants, était la première à tester une telle hypothèse. Bien qu’elle n’ait pas permis de démontrer une telle relation de modération, compte tenu de certaines limites, il apparaît nécessaire de réévaluer ce modèle modérateur au sein d’un d’échantillon de plus grande taille. / Borderline personality disorder (BPD) is characterized by negative Urgency, one of the impulsivity facets. However the model of personality traits can’t explain the varieties of expression and severity of impulsive behaviors which can be directed against self or others in BPD. Integrating the object relations model with the personality traits leads to an improved understanding of this variability. In object relations theory, identity diffusion is specific to borderline organization. It is characterized by a lack of integration of the conceptions of self and others derived from an excessive split between positive and negative affects invested in self and others images. This diffusion is associated with a deficit of Ego and Superego structures. Level of identity integration would modulate the relationship between high negative urgency and the forms and severity of impulsive behaviors. This study is the first to evaluate this hypothesis. Data collected from students sample have not demonstrated any moderating effect because of some limitations in the study. Nevertheless, the Identity diffusion index was as expected negatively correlated with many variables related to impulsivity such as borderline impulsivity (r=-.23), physical aggression (r=-.31), urgency trait (r=-.31) and acting out (r=-30). However, this hypothesis needs to be tested with larger samples.

ADHD affects executive functions and pharmacological treatment is the most common intervention. Medication is ineffective for some and psychosocial interventions are scarcely available. CBT that teaches organizational skills for managing ADHD-symptoms has shown promising results. Smartphones can help individuals perform executive tasks such as planning and organizationand they could beefficacious as a support tool for ADHD patients. The current study is aRCT that compares an online course (n=29) based on previouslyeffective CBT treatments for ADHD to a wait-list control (n=29). Theintervention focused on teaching the use of an online calendar and smartphone apps. The intervention brought significant improvement (p < 0.001) to participants regarding ADHD symptoms and 38% of participants were considered clinically significantly improved. This indicates that online treatments using IT-tools for ADHD is effective and that smartphones can be used as a tool for aiding individuals with impairments in executive functions.

Borderline Personality Disorder (BPD), as defined by the DSM-IV-TR (APA, 2000), is a multifaceted mental illness characterized by pervasive instability of interpersonal relationships, self-image, affect and behavior. Despite a growing consensus that the etiological basis of BPD stems from a combination of biological vulnerability and an early developmental history characterized by invalidation, abuse and/or neglect (e.g., Clarkin, Marziali, & Munroe-Blum, 1991; Linehan, 1993), the reasons for the diversity of troubling symptoms (e.g., self-injury, suicidality, mood reactivity, relationship difficulties) remain unclear. Psychopathology theorists differ in their conceptualization of the fundamental problems (e.g., impulsivity vs. identity disturbance vs. emotion dysregulation) underlying BPD and further research is needed to clarify which features are central to the maintenance of the difficulties associated with the disorder. In the current research, the some of the tenets of Linehan’s (1993) biosocial theory of BPD and the core constructs implicated in her conceptualization of the disorder were explored empirically in several samples of undergraduate university students. According to the biosocial theory, difficulties regulating emotions represent the core pathology in the disorder and contribute causally to the development and expression of all other BPD features. The emotional dysregulation is proposed to emerge from transactional interactions between individuals with biological vulnerabilities (i.e., a highly arousable temperament, sensitive to both positive and negative emotional stimuli) and specific environmental influences (i.e., a childhood environment that invalidates their emotional experience). The theory asserts that the dysregulation affects all aspects of emotional responding, resulting in (i) heightened emotional sensitivity, (ii) intense and more frequent responses to emotional stimuli, and (iii) slow return to emotional baseline. Furthermore, Linehan proposed that individuals with BPD lack clarity with respect to their emotions, have difficulties tolerating intense affect, and engage in maladaptive and inadequate emotion modulation strategies. As a result of their dysfunctional response patterns during emotionally challenging events , individuals with BPD fail to learn how to solve the problems contributing to these emotional reactions. In accordance with this theory, a number of hypotheses were tested. First, it was hypothesized that the interaction between temperamental sensitivity and an adverse childhood environment would predict BPD features over and above that predicted by either construct independently. Second, it was hypothesized that BPD traits would be predicted by high levels of emotional dysregulation (affect lability), problems across different aspects of emotional experience (e.g., intensity, awareness, clarity), and deficits in emotion regulation skills (e.g., poor distress tolerance, self-soothing). Based on the initial findings of the research, a series of competing hypotheses were tested that addressed the nature of the emotional, cognitive and motivational mechanisms that may underlie maladaptive behavior in BPD more directly. Prior to testing these hypotheses, it was important to select a set of measures that would best represent these constructs within an undergraduate population. The purpose of Studies 1a and 1b (N = 147 and N = 56, respectively) was to determine the reliability and validity of a series of self-report measures that assess BPD features and to select one questionnaire with high sensitivity (percentage of cases correctly identified) and high specificity (percentage of noncases correctly identified) as a screener for BPD within undergraduate students by comparing the results of the questionnaires against a “gold standard” criterion diagnosis of BPD (as assessed by two semi-structured interviews: DIB-R and IPDE-I). The second goal of these studies was to conduct a preliminary exploratory analysis of the association of scores on the BPD measures and constructs that have been hypothesized to be relevant to the development and maintenance of BPD symptoms (e.g., “Big Five” personality factors, emotional experience, impulsivity). Overall, the findings of Studies 1a and 1b indicated that screening for BPD in an undergraduate population is feasible and there are several questionnaires that may help in the identification of participants for future studies. Specifically, the McLean Screening Instrument for Borderline Personality Disorder (MSI-BPD; Zanarini et al., 2003), International Personality Disorder Examination DSM-IV Screening Questionnaire (IPDE-S; Loranger, 1999) and Borderline Personality Questionnaire (BPQ; Poreh et al., 2006) were all found to be internally consistent and valid screening measures. Furthermore, the results of correlation and regression analyses between dimensions of the “Big Five” and scores on the BPD measures were consistent with previous findings in the literature that BPD is associated with higher scores on neuroticism, lower scores on agreeableness, and to a lesser degree, lower scores on conscientiousness and extraversion. The similarity in results between the current and past studies suggested that individuals in the present samples showed characteristics consistent with that seen in both clinical and nonclinical populations with BPD traits. The results also provided support for the notion that individuals with BPD have a lower threshold (i.e., greater sensitivity) for both sensory and affective stimuli, as well as higher amplitude of emotional response (i.e., greater reactivity) to such stimuli. Furthermore, the findings suggested that those with BPD traits may lack understanding of their emotional state, may be unable to effectively regulate their emotional state, and that their impulsive behavior may be driven by negative affect. The purpose of Study 2 (N = 225) was to test some of the specific tenets of Linehan’s (1993) biosocial theory. The results suggested that BPD traits are associated with numerous dimensions of temperament [e.g., higher levels of negative affect; lower levels of positive affect; lower levels of effortful control; low sensory threshold (i.e., greater sensitivity) for both sensory and affective stimuli; ease of excitation (i.e., greater reactivity to sensory and affective stimuli)] and childhood environment (e.g., authoritarian parenting style, invalidating parenting, neglect, abuse). An examination of the interactions between dimensions of temperament and childhood environment suggested that interactions between (i) ease of excitation (greater reactivity to sensory and affective stimuli) and environment and (ii) trait negative affect and environment, predicted BPD symptoms over and above the temperament and environment variables alone. The results also suggested that a number of other factors are associated with BPD symptoms, including: increased attention to (or absorption in) emotional states, poor emotional clarity, affect lability (particularly anger), poor distress tolerance, and negative urgency (impulsive behavior in the context of negative affect). The association between BPD symptoms and difficulties identifying feelings seemed to be mediated by affect lability and negative urgency. Self-soothing and self-attacking did not predict BPD traits over and above the other variables. Wagner and Linehan (1999) also proposed that the intense emotions (and emotional dysregulation) experienced by those with BPD interferes with cognitive functioning and effective problem solving, resulting in poor decisions and the observed harmful behaviors. Other researchers have suggested that the repetitive, self-damaging behavior occurring in the context of BPD may reflect impairments in planning and failure to consider future consequences (e.g., van Reekum et al., 1994). Proponents of this view suggest that individuals with BPD show greater intensity and lability in their emotional response to their environment because they are unable to inhibit or moderate their emotional urges (i.e., impulsivity is at the core of the disorder). The purpose of Study 3 (N = 220) was to characterize decision making in an undergraduate sample of individuals with BPD traits and to ascertain the relative contribution of individual differences in the following areas to any deficits identified in decision making: emotional experience (e.g., increased affective reactivity or lability); reinforcement sensitivity (e.g., sensitivity to reward and/or punishment); impulsivity; executive functioning (measured by an analogue version of the Wisconsin Card Sorting Test); and reversal learning. Decision making was assessed using modified versions of two Iowa Gambling Tasks (IGT-ABCD and IGT-EFGH; Bechara, Damasio, Damasio, & Anderson, 1994; Bechara, Tranel, & Damasio, 2000) that included reversal learning components (i.e., Turnbull et al., 2006). The results of Study 3 showed that participants in the BPD group demonstrated deficits in decision-making as measured by the IGT-ABCD but not on the IGT-EFGH. The results [interpreted in the context of reinforcement sensitivity models, the somatic marker hypothesis (Damasio, 1994) and the “frequency of gain” model e.g., Chiu et al. 2008)] suggested that decision making under uncertainty may be guided by gain-loss frequency rather than long-term outcome for individuals with BPD traits. The results failed to show consistent associations between BPD symptoms and performance on either version of the IGT. Individual differences in emotional experience, executive functioning or reversal learning did not account for the decision-making problems of the BPD group on the IGT-ABCD.