Fabien D’Hondt

Categorical perception of emotional facial expressions in alcohol-dependence.

BACKGROUND Emotional deficits have been widely described in alcohol-dependence, but several subtle and critical emotional decoding abilities remain to be investigated. In particular, the ability of alcohol-dependent individuals to process emotionally ambiguous facial stimuli, which are more frequent in everyday life than full emotional facial expressions, remains poorly understood. The present study used a categorical perception paradigm to evaluate the identification of mixed emotional facial expressions among alcohol-dependent participants. METHOD Nineteen recently detoxified participants with alcohol-dependence and 19 healthy controls were presented with facial stimuli depicting four emotional facial expressions (happy, angry, sad, and neutral), morphed along continua between each possible pair of emotions. Participants had to indicate the predominant emotion within the randomly presented facial stimuli. For each emotional category, a logistic function that estimated the percentage of identification according to the morph steps was adjusted for each participants data. RESULTS While there was no significant group difference regarding the response slope (p=0.502, ηp(2)=0.014), the identification threshold was significantly increased in alcohol-dependent participants compared to controls (p=0.007, ηp(2)=0.204), independently of the emotional category. CONCLUSIONS The categorical perception of emotional facial expression per se appeared preserved in alcohol-dependence, but alcohol-dependent participants exhibited a bias in emotional facial expression decoding characterized by a global under-identification. This study is the first to evidence a deficit of alcohol-dependent individuals in the processing of ambiguous emotional facial expressions by using this emotional continuum paradigm measuring the categorical perception effect.

The multiple neural networks of familiarity: A meta-analysis of functional imaging studies

Recent research has demonstrated the critical role of the feeling of familiarity in recognition memory. Various neuroimaging paradigms have been developed to identify the brain regions that sustain the processing of familiarity; however, there is still considerable controversy about the functional significance of each brain region implicated in familiarity-based retrieval. Here, we focused on the differences between paradigms that assess familiarity, with or without the encoding phase. We used the activation likelihood estimation (ALE) algorithm to conduct a whole-brain meta-analysis of neuroimaging studies that involved a familiarity task. Sixty-nine studies, performed in healthy subjects to determine the specific functions of the identified regions in familiarity processing, were finally selected. Distinct subanalyses were performed according to the experimental procedures used in the original studies. The ALE clusters that were highlighted revealed common activations for paradigms with and without encoding in the prefrontal cortex and in the parietal cortex. Additionally, supplementary activations related to specific familiarity (i.e., without the encoding phase) were observed in the limbic system (i.e., the amygdala, hippocampus, cingulate cortex, and insula) and in the associative sensory areas. The differences in the reported findings for different procedures are possibly due to differences in the concept of familiarity. To aid the exploration of the neural correlates of familiarity in future studies, the strengths and weaknesses of these experimental procedures are critically discussed.

Beyond Cognition: Understanding Affective Impairments in Korsakoff Syndrome

As earlier research on Korsakoff syndrome (KS), a frequent neurological complication of alcohol-dependence (AD), mainly focused on cognition, affective impairments have been little investigated despite their crucial impact in AD. This article proposes new research avenues on this topic by combining two theoretical frameworks: (a) dual-process models, positing that addictions are due to an imbalance between underactivated reflective system and overactivated affective-automatic one; (b) continuity theory, postulating a gradual worsening of cognitive impairments from AD to KS. We suggest that this joint perspective may renew the current knowledge by clarifying the affective-automatic deficits in KS and their interactions with reflective impairments, but also by offering a direct exploration of the continuity between AD and KS regarding reflective and affective-automatic abilities.

Crossmodal processing of emotions in alcohol-dependence and Korsakoff syndrome

ABSTRACT Introduction: Decoding emotional information from faces and voices is crucial for efficient interpersonal communication. Emotional decoding deficits have been found in alcohol-dependence (ALC), particularly in crossmodal situations (with simultaneous stimulations from different modalities), but are still underexplored in Korsakoff syndrome (KS). The aim of this study is to determine whether the continuity hypothesis, postulating a gradual worsening of cognitive and brain impairments from ALC to KS, is valid for emotional crossmodal processing. Methods: Sixteen KS, 17 ALC and 19 matched healthy controls (CP) had to detect the emotion (anger or happiness) displayed by auditory, visual or crossmodal auditory-visual stimuli. Crossmodal stimuli were either emotionally congruent (leading to a facilitation effect, i.e. enhanced performance for crossmodal condition compared to unimodal ones) or incongruent (leading to an interference effect, i.e. decreased performance for crossmodal condition due to discordant information across modalities). Reaction times and accuracy were recorded. Results: Crossmodal integration for congruent information was dampened only in ALC, while both ALC and KS demonstrated, compared to CP, decreased performance for decoding emotional facial expressions in the incongruent condition. Conclusions: The crossmodal integration appears impaired in ALC but preserved in KS. Both alcohol-related disorders present an increased interference effect. These results show the interest of more ecological designs, using crossmodal stimuli, to explore emotional decoding in alcohol-related disorders. They also suggest that the continuum hypothesis cannot be generalised to emotional decoding abilities.

New Perspectives in the Exploration of Korsakoff’s Syndrome: The Usefulness of Neurophysiological Markers

This perspective aims at underlining the usefulness of event-related potentials (ERP) to better understand the brain correlates of Korsakoff’s syndrome (KS), a neuropsychiatric disease characterized by severe memory impairment and most frequently resulting as a neurological complication of alcohol-dependence (AD). While ERP have been broadly used in AD, it has up to now been very little applied in KS or in the comparison of KS and AD. Within the framework of dual-process models, an influential theory postulating that addictive states result from an imbalance between under-activated reflective system and over-activated automatic-affective one, this paper proposes: (1) a brief synthesis of the main results of ERP studies in AD and KS, and (2) new research avenues using ERP to identify the electrophysiological correlates of cognitive and emotional dysfunction in KS. These experimental perspectives aim at exploring the continuity hypothesis, which postulates a gradient of impairments from AD to KS. We conclude on the possibility of developing neuropsychological strategies with electrophysiological follow-up to ensure KS diagnosis and test the efficacy of patient’s neurocognitive rehabilitation.

Explicit and implicit emotional processing in peripheral vision: A saccadic choice paradigm

We investigated explicit and implicit emotional processing in peripheral vision using saccadic choice tasks. Emotional-neutral pairs of scenes were presented peripherally either at 10, 30 or 60° away from fixation. The participants had to make a saccadic eye movement to the target scene: emotional vs neutral in the explicit task, and oval vs rectangular in the implicit task. In the explicit task, pleasant scenes were reliably categorized as emotional up to 60° while performance for unpleasant scenes decreased between 10° and 30° and did not differ from chance at 60°. Categorization of neutral scenes did not differ from chance. Performance in the implicit task was significantly better for emotional targets than for neutral targets at 10° and this beneficial effect of emotion persisted only for pleasant scenes at 30°. Thus, these findings show that explicit and implicit emotional processing in peripheral vision depends on eccentricity and valence of stimuli.

Executive Impairments in Binge Drinking: Evidence for a Specific Performance-Monitoring Difficulty during Alcohol-Related Processing

This study evaluated inhibition and performance-monitoring abilities through the explicit processing of alcohol cues. Twenty-two binge drinkers (BD) and 22 control participants performed a speeded Go/No-Go task using pictures of alcohol and soft cans as Go and No-Go targets. This task measures inhibitory control and performance monitoring (i.e., task adjustment through errors and feedback processing) during the explicit processing of alcohol cues. Groups did not significantly differ regarding inhibition abilities. However, BD had poorer performance-monitoring abilities, reflected by a difficulty to adjust after errors, especially when these errors were related to alcohol cues. These findings suggest that the explicit processing of alcohol cues negatively impacts cognitive abilities among BD.

Psychiatric comorbidities associated with a positive screening using the Montreal Cognitive Assessment (MoCA) test in subjects with severe alcohol use disorder

BACKGROUND Patients with severe alcohol use disorder (SAUD) frequently show cognitive deficits that can be efficiently identified using screening tools such as the Montreal Cognitive Assessment (MoCA) test. These cognitive deficits, which reduce the efficacy of therapeutic interventions and may contribute to dropout and relapse, could be, however, partly due to a treatable other cause. Accordingly, this exploratory study examined whether psychiatric comorbid disorders can induce a positive MoCA screening among recently detoxified SAUD subjects. METHODS One hundred recently detoxified patients with SAUD were divided into two groups according to whether they presented cognitive deficits using the MoCA. Groups were compared for demographic data, SAUD severity, impulsivity, and psychiatric comorbidities. The significant parameters were then introduced in a logistic regression model to establish their relative contributions in a positive MoCA status in SAUD subjects. RESULTS Among the significant parameters revealed by the bivariable analyses, agoraphobia and current depressive episode were found to be significant predictors of the MoCA status in the multivariable comparisons. CONCLUSIONS A positive MoCA screening for cognitive impairments among post-detoxification SAUD patients could also be related to comorbid agoraphobia and depressive episode rather than to SAUD itself. A comprehensive psychiatric assessment must be performed in SAUD patients so that other potential causes of cognitive deficits, in particular with regard to mood and anxiety disorders, can be identified and treated.

Electrophysiological correlates of emotional crossmodal processing in binge drinking

Emotional crossmodal integration (i.e., multisensorial decoding of emotions) is a crucial process that ensures adaptive social behaviors and responses to the environment. Recent evidence suggests that in binge drinking—an excessive alcohol consumption pattern associated with psychological and cerebral deficits—crossmodal integration is preserved at the behavioral level. Although some studies have suggested brain modifications during affective processing in binge drinking, nothing is known about the cerebral correlates of crossmodal integration. In the current study, we asked 53 university students (17 binge drinkers, 17 moderate drinkers, 19 nondrinkers) to perform an emotional crossmodal task while their behavioral and neurophysiological responses were recorded. Participants had to identify happiness and anger in three conditions (unimodal, crossmodal congruent, crossmodal incongruent) and two modalities (face and/or voice). Binge drinkers did not significantly differ from moderate drinkers and nondrinkers at the behavioral level. However, widespread cerebral modifications were found at perceptual (N100) and mainly at decisional (P3b) stages in binge drinkers, indexed by slower brain processing and stronger activity. These cerebral modifications were mostly related to anger processing and crossmodal integration. This study highlights higher electrophysiological activity in the absence of behavioral deficits, which could index a potential compensation process in binge drinkers. In line with results found in severe alcohol-use disorders, these electrophysiological findings show modified anger processing, which might have a deleterious impact on social functioning. Moreover, this study suggests impaired crossmodal integration at early stages of alcohol-related disorders.

Implicit Recognition of Familiar and Unfamiliar Faces in Schizophrenia: A Study of the Skin Conductance Response in Familiarity Disorders

Objective Familiarity is a subjective sensation that contributes to person recognition. This process is described as an emotion-based memory-trace of previous meetings and could be disrupted in schizophrenia. Consequently, familiarity disorders could be involved in the impaired social interactions observed in patients with schizophrenia. Previous studies have primarily focused on famous people recognition. Our aim was to identify underlying features, such as emotional disturbances, that may contribute to familiarity disorders in schizophrenia. We hypothesize that patients with familiarity disorders will exhibit a lack of familiarity that could be detected by a flattened skin conductance response (SCR). Method The SCR was recorded to test the hypothesis that emotional reactivity disturbances occur in patients with schizophrenia during the categorization of specific familiar, famous and unknown faces as male or female. Forty-eight subjects were divided into the following 3 matched groups with 16 subjects per group: control subjects, schizophrenic people with familiarity disorder, and schizophrenic people without familiarity disorders. Results Emotional arousal is reflected by the skin conductance measures. The control subjects and the patients without familiarity disorders experienced a differential emotional response to the specific familiar faces compared with that to the unknown faces. Nevertheless, overall, the schizophrenic patients without familiarity disorders showed a weaker response across conditions compared with the control subjects. In contrast, the patients with familiarity disorders did not show any significant differences in their emotional response to the faces, regardless of the condition. Conclusion Only patients with familiarity disorders fail to exhibit a difference in emotional response between familiar and non-familiar faces. These patients likely emotionally process familiar faces similarly to unknown faces. Hence, the lower feelings of familiarity in schizophrenia may be a premise enabling the emergence of familiarity disorders.