Jean Gagnon

GABA A Receptors Predict Aversion-Related Brain Responses: An fMRI-PET Investigation in Healthy Humans

The perception of aversive stimuli is essential for human survival and depends largely on environmental context. Although aversive brain processing has been shown to involve the sensorimotor cortex, the neural and biochemical mechanisms underlying the interaction between two independent aversive cues are unclear. Based on previous work indicating ventromedial prefrontal cortex (vmPFC) involvement in the mediation of context-dependent emotional effects, we hypothesized a central role for the vmPFC in modulating sensorimotor cortex activity using a GABAergic mechanism during an aversive–aversive stimulus interaction. This approach revealed differential activations within the aversion-related network (eg, sensorimotor cortex, midcingulate, and insula) for the aversive–aversive, when compared with the aversive–neutral, interaction. Individual differences in sensorimotor cortex signal changes during the aversive–aversive interaction were predicted by GABAA receptors in both vmPFC and sensorimotor cortex. Together, these results demonstrate the central role of GABA in mediating context-dependent effects in aversion-related processing.

Definition of Impulsivity and Related Terms Following Traumatic Brain Injury: A Review of the Different Concepts and Measures Used to Assess Impulsivity, Disinhibition and other Related Concepts

Impulsivity is a common and debilitating sequela following traumatic brain injury (TBI), but there is no consensual definition or measure to assess this construct. The following review aims to elucidate the differences and resemblances between impulsivity, disinhibition and other related terms following brain injury and the instruments that are commonly used to measure these constructs. To do so, a search through different databases was conducted in order to find articles that mention and define impulsivity, disinhibition, impulse control, regulation deficits, dyscontrol and risky behavior. The concepts that stand out from the literature, the measures used, the similarities, the differences between these concepts are observed. The fit with the UPPS model of impulsivity, according to which impulsivity is a multidimensional concept composed of four distinct dimensions (urgency, perseverance, premeditation and sensation-seeking) is discussed.

Inhibition and object relations in borderline personality traits after traumatic brain injury

This study aims to assess the nature and severity of borderline traits after traumatic brain injury (TBI). Thirty subjects with moderate or severe TBI were compared to 30 normal controls on the Revised Diagnostic Interview for Borderlines (DIB-R), a dimensional measure of borderline traits, the Go-no go inhibition task, the Complexity of Representations of People and Affect-Tone Relationships Paradigms, two scales from the Social Cognition and Object Relations Scale (SCORS) evaluating the quality of object relations, an estimation of pre-morbid borderline severity, the Beck Depression Inventory (BDI) and various neuropsychological measures. Results indicate that TBIs present more borderline symptoms and traits than controls. However, the severity of borderline symptomatology remains comparatively low for the vast majority. As expected, the TBI group showed a poorer performance on the Go-no go task, a characteristic neuropsychological inhibition deficit. Yet, both samples present similar profiles on the SCORS. Finally, the DIB-R was correlated with the Affect-Tone scale, the BDI and with the pre-morbid severity estimation. Results suggest that post-TBI borderline traits remain rare and relate more to the affective quality of object relations, negative affects and pre-morbid borderline pathology than inhibition deficits.

A multifactorial and integrative approach to impulsivity in neuropsychology: insights from the UPPS model of impulsivity

ABSTRACT Risky and excessive behaviors, such as aggressive and compulsive behaviors, are frequently described in patients with brain damage and have dramatic psychosocial consequences. Although there is strong evidence that impulsivity constitutes a key factor at play in these behaviors, the literature about impulsivity in neuropsychology is to date scarce. In addition, examining and understanding these problematic behaviors requires the assumption that impulsivity is a multidimensional construct. Consequently, this article aims at shedding light on frequent risky and excessive behaviors in patients with brain damage by focusing on a unified, comprehensive, and well-validated model, namely, the UPPS model of impulsivity. This model considers impulsivity as a multidimensional construct that includes four facets: urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. Furthermore, we discuss the psychological mechanisms underlying the dimensions of impulsivity, as well as the laboratory tasks designed to assess each mechanism and their neural bases. We then present a scale specifically designed to assess these four dimensions of impulsivity in patients with brain damage and examine the data regarding this multidimensional approach to impulsivity in neuropsychology. This review supports the need to adopt a multifactorial and integrative approach toward impulsive behaviors, and the model presented provides a valuable rationale to disentangle the nature of brain systems and mechanisms underlying impulsive behaviors in patients with brain damage. It may also foster further relevant research in the field of impulsivity and improve assessment and rehabilitation of impulsive behaviors in clinical settings.

What Money Can’t Buy: Different Patterns in Decision Making About Sex and Money Predict Past Sexual Coercion Perpetration

Self-reported impulsivity has been found to predict the perpetration of sexual coercion in both sexual offenders and male college students. Impulsivity can be conceptualized as a generalized lack of self-control (i.e., general perspective) or as a multifaceted construct that can vary from one context to the other (i.e., domain-specific perspective). Delay discounting, the tendency to prefer sooner smaller rewards over larger delayed rewards, is a measure of impulsive decision making. Recent sexual adaptations of delay discounting tasks can be used to test domain-specific assumptions. The present study used the UPPS-P impulsivity questionnaire, a standard money discounting task, and a sexual discounting task to predict past use of sexual coercion in a sample of 98 male college students. Results indicated that higher negative urgency scores, less impulsive money discounting, and more impulsive sexual discounting all predicted sexual coercion. Consistent with previous studies, sexuality was discounted more steeply than money by both perpetrators and non-perpetrators of sexual coercion, but this difference was twice as large in perpetrators compared to non-perpetrators. Our study identified three different predictors of sexual coercion in male college students: a broad tendency to act rashly under negative emotions, a specific difficulty to postpone sexual gratification, and a pattern of optimal non-sexual decision making. Results highlight the importance of using multiple measures, including sexuality-specific measures, to get a clear portrait of the links between impulsivity and sexual coercion.

Neural mechanisms underlying attribution of hostile intention in nonaggressive individuals: An ERP study.

Although the perception of hostile intentions in other people can have a clear adaptive function, researchers have paid little attention to the capacity of nonaggressive individuals to infer hostile intentions in others. The goal of the present study was to study brain mechanisms associated with expectations of hostile/non-hostile intent and their on-line evaluation. Scenarios with a hostile versus non-hostile social context followed by a characters ambiguous aversive behavior were presented to readers, and we recorded and analyzed event-related brain potentials (ERPs) to critical words that disambiguated the hostile versus non-hostile intent behind the behavior. Fifty nonaggressive individuals participated in the study. Non-hostile critical words that violated hostile intention expectations elicited a larger negative-going ERP deflection with central and posterior maximums between 400 and 600ms after word onset compatible with an N400 effect. Finally, there were marginally significant correlations between N400 effect sizes and hostile as well as neutral attribution bias measured by a self-report questionnaire. The results suggest that nonaggressive individuals evaluate rapidly, on-line, their attributions of the hostile intent of others. The methodology we developed provides the field with a new paradigm with which to study social attributions of hostile intent likely to contribute to hostile or aggressive reactions.

A French adaptation of the Overt Behaviour Scale (OBS) measuring challenging behaviours following acquired brain injury: The Échelle des comportements observables (ÉCO)

Abstract Purpose: To develop a French version of the Overt Behaviour Scale (OBS) and examine some of its psychometric properties. Methods: The scale was adapted and validated according to standard guidelines for cross-cultural adaptation of questionnaires (Échelle des comportements observables; ÉCO). The reliability and construct validity of the ÉCO were studied among 29 inpatients and outpatients who sustained an acquired brain injury. The instruments were administered by 12 clinicians located at eight rehabilitation centres and the local brain injury association. Results: The ÉCO provided behaviour profile descriptives much like the original scale. It showed excellent reliability and good convergent and divergent validity, as reflected by significant associations with other measures that contained similar behavioural items and by the absence of signification correlations with broader constructs such as physical and cognitive abilities. Conclusion: This study provides evidence that the ÉCO behaves much like the original OBS, has promising initial findings with respect to reliability and validity and is a valuable research and clinical instrument to assess the severity and typology of challenging behaviour after an acquired brain injury and to monitor the evolution of behaviours after intervention in French and bilingual communities.

Relationship between Two Dimensions of Object Relations and Group Psychotherapy Attendance Rate in Borderline Personality Disorder Individuals

Aim: Recent studies showed that the quality of object relations in patients with personality disorders predict individual psychotherapy attendance rate. However, associations between these variables have led to inconsistent results for group psychotherapy. The aim of the present study was to verify whether two dimensions of object relations are associated with rates of attendance at group psychotherapy sessions. Methods: Thematic Apperception Test narratives of forty-one outpatients with borderline personality disorder (BPD) enrolled in a psychodynamic group therapy over a period of one year were rated on two variables of the Social Cognition and Object Relations Scale (SCORS): affective quality of representations and emotional investment in relationship. Results: Results indicated that these two affective dimensions of object relations were positively correlated with rate of attendance at group psychotherapy sessions after controlling for age of the participant. Conclusion: These results suggest that the quality of object relations could be a potential predictor for group therapy attendance. The results are discussed by taking into account the particular aspects of relational issues in group psychotherapy as opposed to individual psychotherapy.

Response to Hypothetical Social Scenarios in Individuals with Traumatic Brain Injury Who Present Inappropriate Social Behavior: A Preliminary Report

Background: Very little research thus far has examined the decision making that underlies inappropriate social behavior (ISB) post-TBI (traumatic brain injury). Objectives: To verify the usefulness of a new instrument, the Social Responding Task, for investigating whether, in social decision making, individuals with TBI, who present inappropriate social behavior (ISB), have difficulty anticipating their own feelings of embarrassment and others’ angry reactions following an ISB. Methods: Seven subjects with TBI presenting with inappropriate social behavior (TBI-ISB), 10 presenting with appropriate social behavior (TBI-ASB), and 15 healthy controls were given 12 hypothetical scenarios three times, each time ending with a different behavioral response. Subjects were asked to gauge the likelihood of their displaying the behavior in that situation (part A) and of it being followed by an angry reaction from the other or by feelings of embarrassment in themselves (part B). Results: TBI-ISB subjects scored higher than TBI-ASB and healthy controls on a scale of likelihood of displaying an ISB. Results regarding expectations of angry reactions from others and feelings of embarrassment after an ISB were similar among groups. Negative correlations between endorsement of an inappropriate behavior and anticipation of negative emotional consequences were significant for both TBI-ASB and control subjects, but not for TBI-ISB subjects. Conclusions: Results suggest that the TBI-ISB participants were likely to endorse an ISB despite being able to anticipate a negative emotional response in themselves or others, suggesting that there were other explanations for their poor behavior. A self-reported likely response to hypothetical social scenarios can be a useful approach for studying the neurocognitive processes behind the poor choices of individuals with TBI-ISB, but the task needs further validation studies. A comprehensive discussion follows on the underlying mechanisms affecting social behaviors after a TBI.

Relationships Between Hostile Attribution Bias, Negative Urgency, and Reactive Aggression

Negative urgency defined as the tendency to act rashly when faced with intense negative emotions and hostile attribution bias (HAB) which refers to the tendency to interpret the intention of others as hostile when social context cues are ambiguous are two key psychological factors underlying reactive aggression. However, the specific associations between these factors in relation to reactive aggression have not been tested yet with competing models. The objective of the study was to test three putative models: (1) negative urgency moderates the association between HAB and reactive aggression; (2) HAB mediates the link between negative urgency and reactive aggression; (3) negative urgency mediates the relation between HAB and reactive aggression. One-hundred seventy-six participants were given self-report questionnaires to assess impulsivity, reactive aggression, as well as vignettes featuring a social situation measuring HAB in response to an ambiguous social provocation. The results showed that negative urgency constitutes a significant mediator in the association between HAB and reactive aggression. These results provide valuable insight into the cognitive processes underlying reactive aggression and may hold implications for diagnosis and intervention on aggressive behaviors.