Xavier Noël

A neurocognitive approach to understanding the neurobiology of addiction.

Recent concepts of addiction to drugs (e.g. cocaine) and non-drugs (e.g. gambling) have proposed that these behaviors are the product of an imbalance between three separate, but interacting, neural systems: an impulsive, largely amygdala-striatum dependent, neural system that promotes automatic, habitual and salient behaviors; a reflective, mainly prefrontal cortex dependent, neural system for decision-making, forecasting the future consequences of a behavior, and inhibitory control; and the insula that integrates interoception states into conscious feelings and into decision-making processes that are involved in uncertain risk and reward. These systems account for poor decision-making (i.e. prioritizing short-term consequences of a decisional option) leading to more elevated addiction risk and relapse. This article provides neural evidence for this three-systems neural model of addiction.

Alcohol cues increase cognitive impulsivity in individuals with alcoholism

BackgroundIndividuals with alcoholism are characterized by both attentional bias for alcohol cues and prepotent response inhibition deficit. We tested the hypothesis that alcoholics exhibit greater cognitive disinhibition when the response to be suppressed is associated with alcohol-related information.MethodsForty recently detoxified individuals with alcoholism were compared with 40 healthy non-substance abusers on the “Alcohol-Shifting Task”, a variant of the go/no-go paradigm requiring a motor response to targets and no response to distracters. The aim was to test the ability of alcoholics to discriminate between alcohol-related and neutral words. Sometimes, the alcohol-related words were the targets for the “go” response, with neutral words as distracters, sometimes the reverse. Several shifts in target type occurred during the task.ResultsAlcoholics made significantly more commission errors (i.e., press a key when a distracter displayed) and more omission errors (i.e., not press a key when a target displayed) than controls. Moreover, the number of commission errors was greater in alcoholics when alcohol-related stimuli had to be detected.ConclusionsThese results demonstrate that alcoholics exhibit a basic prepotent response inhibition deficit, which is enhanced when the response to be suppressed is related to alcohol. We discuss clinical and theoretical implications of these findings.

Response inhibition deficit is involved in poor decision making under risk in nonamnesic individuals with alcoholism.

Individuals with alcoholism exhibit poor decision making as reflected by their continued alcohol use despite encountering problems and by low performance in laboratory tasks of decision making. Here, the authors investigated the relative contribution of several distinct processes of executive functions in performance on the Iowa Gambling Task (IGT; A. Bechara, A. R. Damasio, H. Damasio, & S. W. Anderson, 1994) in recently detoxified individuals with alcoholism. Compared to matched healthy participants, individuals with alcoholism showed below-normal scores in the last 20 trials of the IGT as well as on other tasks of executive functions, specifically those assessing the capacity to manipulate information stored in working memory, detect abstract rules, or inhibit prepotent responses. Prepotent response inhibition best predicted performance in the late trials of the IGT, that is, when participants have likely acquired knowledge about the reward/punishment contingencies of the task. These results underline the important role that response inhibition plays in decision making, especially in risky situations, when knowledge of the probability of a given outcome becomes available (i.e. decisions under risk).

Impaired emotional facial expression recognition in alcoholics, opiate dependence subjects, methadone maintained subjects and mixed alcohol-opiate antecedents subjects compared with normal controls.

The present study aims to explore whether an impairment in emotional facial expressions (EFE) decoding is specific to alcoholism compared with opiate dependence. An EFE decoding test consisting of 16 photographs of EFE portraying happiness, anger, sadness and disgust was administered to five different groups of 30 subjects each: recently detoxified alcoholics (RA); opiate addicts under methadone maintenance treatment (OM); detoxified opiate addicts (OA); detoxified subjects with both alcohol and opiate dependence antecedents (DAO); and normal controls (NC). Repeated measures analysis of variance using a multivariate approach was conducted on EFE decoding accuracy scores with group as the between-subjects factor. Accuracy scores were significantly lower in RA and DAO than in OM and OA, which had significantly lower scores than NC. Low accuracy scores in RA and DAO confirm previous results indicating that alcoholism is associated with impaired EFE recognition. Results in OM and OA indicate that opiate dependence is also associated with an impaired EFE decoding but less than in alcoholism. Alcohol and opiate chronic consumption could both exercise a deleterious effect on EFE-decoding brain function, alcohol having the most severe impact. Alternatively, EFE-decoding problems could be present before the development of alcohol and opiate dependence, with an additional effect of chronic alcohol consumption on EFE decoding. In this context, EFE-decoding impairment could reflect a more general emotional intelligence deficit in addicted populations.

Is the P300 deficit in alcoholism associated with early visual impairments (P100, N170)? An oddball paradigm

OBJECTIVE Studies exploring chronic alcoholism with event-related potentials (ERPs) have shown delayed latency and reduced amplitude of the P300, a long-lasting positive potential reflecting decisional processing. This P300 deficit in alcoholism is generally interpreted as a disturbance in central nervous system inhibition or in memory/attention. The present study aimed at identifying if this electrophysiological deficit is already present on earlier components, and advances a new hypothesis concerning the interpretation of the P300 alteration. METHODS Patients suffering from alcoholism and matched healthy controls had to detect, in an oddball paradigm, emotional faces among a succession of neutral faces. Behavioral performance and ERP data (recorded from 32 electrodes) were analyzed. RESULTS In line with previous studies, data showed that alcoholism led to a P300 deficit. Moreover, we observed for the first time that this deficit begins at earlier visual (P100) and face-processing (N170) stages, and we found high positive correlations between P100, N170 and P300 for amplitude and latency values, suggesting cumulative deficits on the cognitive continuum. CONCLUSIONS We suggest that the P300 deficit observed in chronic alcoholism could be linked to earlier visuo-spatial deficits rather than being an impairment of the specific processes linked to the P300. SIGNIFICANCE These results call for reconsidering the interpretation of P300 impairments at a fundamental and clinical level, and shows that earlier ERP components must be taken into account in future studies.

Major depression is associated with impaired processing of emotion in music as well as in facial and vocal stimuli

BACKGROUND The processing of emotional stimuli is thought to be negatively biased in major depression. This study investigates this issue using musical, vocal and facial affective stimuli. METHODS 23 depressed in-patients and 23 matched healthy controls were recruited. Affective information processing was assessed through musical, vocal and facial emotion recognition tasks. Depression, anxiety level and attention capacity were controlled. RESULTS The depressed participants demonstrated less accurate identification of emotions than the control group in all three sorts of emotion-recognition tasks. The depressed group also gave higher intensity ratings than the controls when scoring negative emotions, and they were more likely to attribute negative emotions to neutral voices and faces. LIMITATIONS Our in-patient group might differ from the more general population of depressed adults. They were all taking anti-depressant medication, which may have had an influence on their emotional information processing. CONCLUSIONS Major depression is associated with a general negative bias in the processing of emotional stimuli. Emotional processing impairment in depression is not confined to interpersonal stimuli (faces and voices), being also present in the ability to feel music accurately.

Iowa Gambling Task (IGT): twenty years after – gambling disorder and IGT

The Iowa Gambling Task (IGT) involves probabilistic learning via monetary rewards and punishments, where advantageous task performance requires subjects to forego potential large immediate rewards for small longer-term rewards to avoid larger losses. Pathological gamblers (PG) perform worse on the IGT compared to controls, relating to their persistent preference toward high, immediate, and uncertain rewards despite experiencing larger losses. In this contribution, we review studies that investigated processes associated with poor IGT performance in PG. Findings from these studies seem to fit with recent neurocognitive models of addiction, which argue that the diminished ability of addicted individuals to ponder short-term against long-term consequences of a choice may be the product of an hyperactive automatic attentional and memory system for signaling the presence of addiction-related cues (e.g., high uncertain rewards associated with disadvantageous decks selection during the IGT) and for attributing to such cues pleasure and excitement. This incentive-salience associated with gambling-related choice in PG may be so high that it could literally “hijack” resources [“hot” executive functions (EFs)] involved in emotional self-regulation and necessary to allow the enactment of further elaborate decontextualized problem-solving abilities (“cool” EFs). A framework for future research is also proposed, which highlights the need for studies examining how these processes contribute specifically to the aberrant choice profile displayed by PG on the IGT.

Dissociation between affective and cognitive empathy in alcoholism : a specific deficit for the emotional dimension.

BACKGROUND Emotional impairments constitute a crucial and widely described dimension of alcoholism, but several affective abilities are still to be thoroughly explored among alcohol-dependent patients. This is particularly true for empathy, which constitutes an essential emotional competence for interpersonal relations and has been shown to be highly impaired in various psychiatric states. The present study aimed at exploring empathic abilities in alcoholism, and notably the hypothesis of a differential deficit between emotional and cognitive empathy. METHODS Empathy abilities were evaluated among 30 recently detoxified inpatients diagnosed with alcohol dependence and 30 paired healthy controls, using highly validated questionnaires (Interpersonal Reactivity Index [J Pers Soc Psychol44:113] and Empathy Quotient [J Autism Dev Disord34:163]). Correlational analyses were performed to evaluate the links between empathy scores and psychopathological measures (i.e., depression, anxiety, interpersonal problems, and alexithymia). RESULTS When psychiatric comorbities are controlled for, alcoholism is not associated with a general empathy deficit, but rather with a dissociated pattern combining impaired emotional empathy and preserved cognitive one. Moreover, this emotional empathy deficit is not associated with depression or anxiety scores, but is negatively correlated with alexithymia and the severity of interpersonal problems. CONCLUSIONS At the theoretical level, this first observation of a specific deficit for emotional empathy in alcoholism, combined with the exact inverse pattern observed in other psychiatric populations, leads to a double-dissociation, which supports the notion that emotional and cognitive empathy are 2 distinct abilities. At the clinical level, this deficit calls for considering emotional empathy rehabilitation as a crucial concern in psychotherapy.

Alcohol-Related Context Modulates Performance of Social Drinkers in a Visual Go/No-Go Task: A Preliminary Assessment of Event-Related Potentials

Background Increased alcohol cue-reactivity and altered inhibitory processing have been reported in heavy social drinkers and alcohol-dependent patients, and are associated with relapse. In social drinkers, these two processes have been usually studied separately by recording event-related potentials (ERPs) during rapid picture presentation. The aim of our study was to confront social drinkers to a task triggering high alcohol cue-reactivity, to verify whether it specifically altered inhibitory performance, by using long-lasting background picture presentation. Methods ERP were recorded during visual Go/No-Go tasks performed by social drinkers, in which a frequent Go signal (letter “M”), and a rare No-Go signal (letter “W”) were superimposed on three different types of background pictures: neutral (black background), alcohol-related and non alcohol-related. Results Our data suggested that heavy social drinkers made more commission errors than light drinkers, but only in the alcohol-related context. Neurophysiologically, this was reflected by a delayed No-Go P3 component. Conclusions Elevated alcohol cue-reactivity may lead to poorer inhibitory performance in heavy social drinkers, and may be considered as an important vulnerability factor in developing alcohol misuse. Prevention programs should be designed to decrease the high arousal of alcohol stimuli and strengthen cognitive control in young, at-risk individuals.

Decision making under ambiguity but not under risk is related to problem gambling severity

The aim of the present study was to examine the relationship between problem gambling severity and decision-making situations that vary in two degrees of uncertainty (probability of outcome is known: decision-making under risk; probability of outcome is unknown: decision-making under ambiguity). For this purpose, we recruited 65 gamblers differing in problem gambling severity and 35 normal controls. Decision-making under ambiguity was assessed with the Iowa Gambling Task (IGT) and the Card Playing Task (CPT). Decision-making under risk was assessed with the Coin Flipping Task (CFT) and the Cups Task. In addition, we included an examination of two working memory components (verbal storage and dual tasking). Results show that problem gamblers performed worse than normal controls on both ambiguous and risky decision-making. Higher problem gambling severity scores were associated with poorer performance on ambiguous decision-making tasks (IGT and CPT) but not decision-making under risk. Additionally, we found that dual task performance correlated positively with decision-making under risk (CFT and Cups tasks) but not with decision-making under ambiguity (IGT and CPT). These results suggest that impairments in decision-making under uncertain conditions of problem gamblers may represent an important neurocognitive mechanism in the maintenance of their problem gambling.