Biomedical subjects

Antoine Bechara

Publications and source records attributed to Antoine Bechara.

At least 19 recordsLinked to original sources

PubMed2007

Decisions under ambiguity and decisions under risk: correlations with executive functions and comparisons of two different gambling tasks with implicit and explicit rules.

We conducted two experiments with healthy subjects to investigate the possible relationships between Iowa Gambling Task (IGT) performance and executive functions as well as IGT performance and decision-making in a task with explicit rules, the Game of Dice Task (GDT). Results indicated that only the last trials of the IGT were correlated with executive functions and GDT performance. We suggest that the IGT taps into two mechanisms of decision-making: decisions under ambiguity in the first trials and decisions under risk in the latter trials. Results have impact on the interpretation of deficient IGT performance in patients with frontal lobe dysfunctions.

Adolescent↗

PubMed2006

Emotion-based decision-making in healthy subjects: short-term effects of reducing dopamine levels.

INTRODUCTION: Converging evidences from animal and human studies suggest that addiction is associated with dopaminergic dysfunction in brain reward circuits. So far, it is unclear what aspects of addictive behaviors are related to a dopaminergic dysfunction. DISCUSSION: We hypothesize that a decrease in dopaminergic activity impairs emotion-based decision-making. To demonstrate this hypothesis, we investigated the effects of a decrease in dopaminergic activity on the performance of an emotion-based decision-making task, the Iowa gambling task (IGT), in 11 healthy human subjects. MATERIALS AND METHODS: We used a double-blind, placebo-controlled, within-subject design to examine the effect of a mixture containing the branched-chain amino acids (BCAA) valine, isoleucine and leucine on prolactin, IGT performance, perceptual competency and visual aspects of visuospatial working memory, visual attention and working memory, and verbal memory. The expectancy-valence model was used to determine the relative contributions of distinct IGT components (attention to past outcomes, relative weight of wins and losses, and choice strategies) in the decision-making process. OBSERVATIONS AND RESULTS: Compared to placebo, the BCAA mixture increased prolactin levels and impaired IGT performance. BCAA administration interfered with a particular component process of decision-making related to attention to more recent events as compared to more distant events. There were no differences between placebo and BCAA conditions for other aspects of cognition. Our results suggest a direct link between a reduced dopaminergic activity and poor emotion-based decision-making characterized by shortsightedness, and thus difficulties resisting short-term reward, despite long-term negative consequences. These findings have implications for behavioral and pharmacological interventions targeting impaired emotion-based decision-making in addictive disorders.

Amino Acids, Branched-Chain↗

PubMed2006

Basic emotions are associated with distinct patterns of cardiorespiratory activity.

The existence of specific somatic states associated with different emotions remains controversial. In this study, we investigated the profile of cardiorespiratory activity during the experience of fear, anger, sadness and happiness. ECG and respiratory activity was recorded in 43 healthy volunteers during the recall and experiential reliving of one or two potent emotional autobiographical episodes and a neutral episode. Univariate statistics indicated that the four emotions differed from each other and from the neutral control condition on several linear and spectral indices of cardiorespiratory activity. Dependent variables were further reduced to five physiologically meaningful factors using an exploratory principal component analysis (PCA). Multivariate analyses of variance and effect size estimates calculated on those factors confirmed the differences between the four emotion conditions. A stepwise discriminant analyses predicting emotions using the PCA factors led to a classification rate of 65.3% for the four emotions (chance=25%; p=0.001) and of 72.0-83.3% for pair-wise discrimination (chance=50%; p's<0.05). These findings may be considered preliminary in view of the small sample on which the multivariate approach has been applied. However, this study emphasizes the need to better characterize the multidimensional factors involved in cardio-respiratory regulation during emotion. These results are consistent with the notion that distinct patterns of peripheral physiological activity are associated with different emotions.

Arousal↗

PubMed2006

Psychophysiological anticipation of positive outcomes promotes advantageous decision-making in normal older persons.

Previous studies have demonstrated that aging has an adverse effect on laboratory decision-making in some older adults, and such findings have important implications for real-world reasoning and judgment. Emotion, and its accompanying somatic responses, is thought to contribute significantly to decision-making. In the present study, we had two objectives: 1) to investigate decision-making in a new sample of elderly participants, using the Iowa Gambling Task (IGT); and 2) to investigate psychophysiological correlates of decision-making, focusing on anticipatory skin conductance responses (SCRs) that participants produce immediately prior to their behavioral response. We hypothesized that the previous behavioral findings would be replicated, and further, that the older adult participants with IGT impairments would show a lack of discriminatory anticipatory SCRs during the IGT. The results supported both predictions. First, a subgroup of the new elderly sample demonstrated impaired decision-making on the IGT, replicating our previous findings. Second, the participants with impaired IGT performance failed to demonstrate discriminatory anticipatory SCRs for advantageous versus disadvantageous choices, whereas participants with normal IGT performance did demonstrate such discrimination; in the latter case, however, SCR magnitude was higher for advantageous decisions (unlike the pattern in young normal adults). Our data lead to the suggestion that strong decision-making abilities among older adults may be a function of positive somatic markers, whereas poor decision-making abilities may arise from an abnormal somatic response generated in anticipation of a future event.

Aged↗

PubMed2006

Skin conductance responses are elicited by the airway sensory effects of puffs from cigarettes.

The airway sensations stimulated by smoking are an important source of hedonic impact (pleasure) for dependent smokers. The learning process by which these sensations become pleasurable is not well understood. The classical conditioning model predicts that airway sensory stimulation will elicit sympathetic arousal that is positively correlated with the hedonic impact that is elicited by airway sensory stimulation. To test this prediction, we measured skin conductance responses (SCRs) and subjective hedonic impact elicited by a series of individual puffs from nicotinized, denicotinized and unlit cigarettes. Nicotinized puffs elicited more subjective hedonic impact than denicotinized and unlit puffs partly as a result of the fact that they provided a greater level of airway sensory stimulation. We found that SCRs were not larger for nicotinized puffs than for denicotinized puffs, but that they were larger for both nicotinized and denicotinized puffs than for unlit puffs. We also found that the average SCR of a subject to denicotinized puffs was positively correlated with the average hedonic impact that a subject obtained from denicotinized puffs. Together, this suggests that SCR magnitude does not reflect within-subject variations in hedonic impact that are due to variations in the level of airway sensory stimulation, but that it does reflect individual differences in the amount of hedonic impact that is derived from a given level of airway sensory stimulation. The results of a post hoc correlation analysis suggest that these individual differences may have been due to variations in the prevailing urge to smoke. The implications of these findings for the classical conditioning model, as well as for other learning models, are discussed.

Adolescent↗

PubMed2006

Impairments of emotion and real-world complex behavior following childhood- or adult-onset damage to ventromedial prefrontal cortex.

The behavioral syndrome resulting from damage to the ventromedial prefrontal (VM) region presents major challenges for clinical assessment and management, stemming from the absence of reliable neurologic or psychometric markers, coupled with often debilitating impairments of decision-making and behavior regulation. Damage to this region disrupts neural circuitry critical for emotion, which in turn may contribute to impairments in real-world competencies. Here we present findings from patients with focal lesions in the VM region acquired either in childhood or adulthood, and show that there is a relationship between emotional dysfunction and impairments in real-world behavioral competencies. Emotion was rated by participants' relatives on dimensions including frustration tolerance, lability, anxiety, and blunted affect. Real-world competencies were rated by the relatives on dimensions including judgment, planning, and initiation, and were evaluated by clinician ratings in areas including social, financial, and occupational function. VM damage resulted in severe disruption of emotion, and this emotional dysfunction accounted for a significant portion of impaired real-world competencies. The long-term impairments associated with childhood-onset lesions were at least as severe as those resulting from adult-onset damage. Greater focus on the contribution of emotional dysfunction to the real-world competencies of patients with damage in the VM region may sharpen their neuropsychological assessment and facilitate rehabilitation efforts.

Adult↗

PubMed2006

Executive dysfunction in substance dependent individuals during drug use and abstinence: an examination of the behavioral, cognitive and emotional correlates of addiction.

Increasing evidence indicates that substance-dependent individuals (SDI) are impaired in executive control tasks relying on different systems within the prefrontal cortex (PFC). Three different functional systems have been described: the dorsolateral prefrontal cortex (DLPC), orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC) circuits. Dysfunction within each PFC system is associated with different behavioral, cognitive, and emotional abnormalities. Few studies have conducted an exhaustive examination of all these different factors in SDI. In this study, SDI (including alcohol, cocaine, and methamphetamine polysubstance users, n=35) were compared with healthy controls (n=36) on a series of behavioral (Frontal Systems Behaviour Scale, FrSBe), cognitive (N-back, Go-No Go, and Wisconsin Card Sorting Tasks), and emotional (International Affective Picture System, IAPS) tasks, each of which was thought to tax a different component of these PFC functional systems. SDI showed greater behavioral problems in the apathy, disinhibition, and executive dysfunction subscales of the FrSBe. Behavioral deficits were significantly associated with several real-life domains in which SDI typically have problems. SDI also showed poorer performance on cognitive tests of working memory, response inhibition and mental flexibility, and abnormal processing of affective images from the IAPS. Cognitive, behavioral, and emotional measures were moderately correlated.

Adult↗

PubMed2006

Time course of attention for alcohol cues in abstinent alcoholic patients: the role of initial orienting.

OBJECTIVE: Addicted people are characterized by enhanced attention for drug cues leading to drug use. However, there is little research on the component processes of attention in individuals with alcoholism. Here, we examine 2 distinct components of attention in abstinent alcohol-dependent individuals and social drinkers of alcohol, that is to say, the initial orienting to alcohol-related cues, and the maintenance of attention to them. METHOD: The present study used an "alcohol" version of the visual probe detection task with alcohol-related or neutral pictures being presented briefly (i.e., 50 ms), to assess initial orienting, or longer (i.e., 500 and 1,250 ms), to assess the maintenance of attention. RESULTS: Only alcoholic patients were faster in detecting a probe displayed immediately after pictures related to alcohol presented for 50 ms than in detecting the same probe replacing non-alcohol-related pictures. However, when pictures were presented for 500 ms, only social alcohol drinkers were faster in detecting the probe replacing alcohol scenes. At a stimulus of 1,250 ms duration, no group showed attentional bias toward alcohol cues. In addition, the severity of alcoholism measured by the total number of prior detoxification treatments was positively correlated with the attentional bias (or "attraction") for alcohol pictures presented for 50 ms. CONCLUSIONS: These results show that, subsequent to initial visual orienting to alcohol-related cues, abstinent patients' attention was disengaged from these stimuli, thus suggesting a visual approach-disengagement attentional pattern. The influence of these findings on relapse was discussed.

Adult↗

PubMed2005

Does gender play a role in functional asymmetry of ventromedial prefrontal cortex?

We found previously in a lesion study that the right-sided sector of the ventromedial prefrontal cortices (VMPCs) was critical for social/emotional functioning and decision-making, whereas the left side appeared to be less important. It so happened that all but one of the subjects in that study were men, and the one woman did not fit the pattern very well. This prompted a follow-up investigation, in which we explored the following question: Does gender play a role in the development of defects in social conduct, emotional functioning and decision-making, following unilateral VMPC damage? We culled from our Patient Registry same-sex pairs of men or women patients who had comparable unilateral VMPC damage in either the left or right hemisphere. Two male pairs and one female pair were formed, and we included two additional women with unilateral right VMPC damage (8 patients in all). The domains of measurement covered social conduct, emotional processing and personality, and decision-making. We found a systematic effect of gender on the pattern of left-right asymmetry in VMPC. In men, there were severe defects following unilateral right VMPC damage, but not following left-sided damage. In women, there were defects following unilateral left VMPC damage; following right-sided damage, however, defects were mild or absent. The findings suggest that men and women may use different strategies to solve similar problems--e.g. men may use a more holistic, gestalt-type strategy, and women may use a more analytic, verbally-mediated strategy. Such differences could reflect asymmetric, gender-related differences in the neurobiology of left and right VMPC sectors.

Adult↗

PubMed2005

Electrophysiological correlates of reward prediction error recorded in the human prefrontal cortex.

Lesion and functional imaging studies have shown that the ventromedial prefrontal cortex is critically involved in the avoidance of risky choices. However, detailed descriptions of the mechanisms that underlie the establishment of such behaviors remain elusive, due in part to the spatial and temporal limitations of available research techniques. We investigated this issue by recording directly from prefrontal depth electrodes in a rare neurosurgical patient while he performed the Iowa Gambling Task, and we concurrently measured behavioral, autonomic, and electrophysiological responses. We found a robust alpha-band component of event-related potentials that reflected the mismatch between expected outcomes and actual outcomes in the task, correlating closely with the reward-related error obtained from a reinforcement learning model of the patient's choice behavior. The finding implicates this brain region in the acquisition of choice bias by means of a continuous updating of expectations about reward and punishment.

Choice Behavior↗

PubMed2005

The dark side of emotion in decision-making: when individuals with decreased emotional reactions make more advantageous decisions.

Can dysfunction in neural systems subserving emotion lead, under certain circumstances, to more advantageous decisions? To answer this question, we investigated how individuals with substance dependence (ISD), patients with stable focal lesions in brain regions related to emotion (lesion patients), and normal participants (normal controls) made 20 rounds of investment decisions. Like lesion patients, ISD made more advantageous decisions and ultimately earned more money from their investments than the normal controls. When normal controls either won or lost money on an investment round, they adopted a conservative strategy and became more reluctant to invest on the subsequent round, suggesting that they were more affected than lesion patients and ISD by the outcomes of decisions made in the previous rounds.

Alcoholism↗

PubMed2005

The airway sensory impact of nicotine contributes to the conditioned reinforcing effects of individual puffs from cigarettes.

Puffs from cigarettes are the fundamental unit of smoking reward. Here, we examined the extent to which reward from puffs can be derived from the airway sensory effect of nicotine, in the absence of a direct central nervous system effect of nicotine. We did this by assessing the self-reported reward obtained from individual puffs from nicotinized, denicotinized and unlit cigarettes within 7 s of inhalation, which is before nicotine had an opportunity to reach the brain. We also assessed the self-reported strength of airway sensations elicited by the puffs. We found that nicotinized puffs were rated as both stronger and more rewarding than denicotinized and unlit puffs. We also found that the extent to which nicotine elicited reward was directly correlated with the extent to which nicotine elicited airway sensations. This indicates that the airway sensory effects of nicotine contribute to the reward from puffs, above and beyond the reward derived from the airway sensory effects of non-nicotine constituents. These findings have implications for the interpretation of studies that use puffs as experimental units to examine nicotine reward. They also have implications for the use of denicotinized and low nicotine cigarettes as aids to smoking cessation.

Adult↗

PubMed2005

The influence of executive functions, sensation seeking, and HIV serostatus on the risky sexual practices of substance-dependent individuals.

From a public health standpoint, identifying factors that contribute to risky sexual practices among substance-dependent individuals is critical, particularly in the context of HIV infection. This study examines the respective contributions of executive neurocognitive functions, sensation seeking, and HIV serostatus in predicting risky sexual practices among poly-substance users (with a history of dependence primarily for cocaine or cocaine/heroin). HIV+ (n=109) and HIV- (n=154) substance-dependent individuals were assessed using three neurocognitive tasks of executive functions: Stroop reaction time, delayed non-matching to sample, and the Iowa Gambling Task. Sensation seeking was assessed using the Sensation Seeking Scale-V. Greater sensation seeking was associated with more risky sexual practices among HIV+ participants, particularly among those who performed best on the Iowa Gambling Task. Our findings indicate that continued risk behavior among HIV+ drug users may be driven by sensation seeking (a personality trait common among drug users); however, the impact of executive functions is less clear.

Adult↗

PubMed2005

Decision making, impulse control and loss of willpower to resist drugs: a neurocognitive perspective.

Here I argue that addicted people become unable to make drug-use choices on the basis of long-term outcome, and I propose a neural framework that explains this myopia for future consequences. I suggest that addiction is the product of an imbalance between two separate, but interacting, neural systems that control decision making: an impulsive, amygdala system for signaling pain or pleasure of immediate prospects, and a reflective, prefrontal cortex system for signaling pain or pleasure of future prospects. After an individual learns social rules, the reflective system controls the impulsive system via several mechanisms. However, this control is not absolute; hyperactivity within the impulsive system can override the reflective system. I propose that drugs can trigger bottom-up, involuntary signals originating from the amygdala that modulate, bias or even hijack the goal-driven cognitive resources that are needed for the normal operation of the reflective system and for exercising the willpower to resist drugs.

Amygdala↗

PubMed2005

Impulsivity and decision making.

The purpose of the present study was to explore the links among the four facets of impulsivity (urgency, lack of premeditation, lack of perseverance, and sensation seeking) proposed by and decision-making processes. Thirty undergraduate students completed a self-report questionnaire evaluating impulsivity as well as a task measuring decision-making processes, the Iowa Gambling Task. Zero-order correlations and multilevel analysis revealed that only lack of premeditation was specifically linked to disadvantageous decisions on the Gambling Task. This suggests that premeditation is related to decision making influenced by somatic (or emotional) markers.

Adult↗

PubMed2005

Decision-making and impulse control after frontal lobe injuries.

PURPOSE OF REVIEW: For a long time, the prefrontal cortex has been considered a 'nonfunctional' brain area, and understanding its function has lagged behind other areas. This is no longer true since appreciation of the vital role that this brain region plays in adaptive behaviors, and especially decision-making, is now evident more than ever. The present review highlights recent progress made in this area of research. RECENT FINDINGS: Decision-making is a term often referred to in the psychological literature as one of the 'executive functions' that play a role in managing (like an executive) other cognitive functions, such as memory, attention, and language. Considerable research efforts have been directed towards differentiating various processes of executive functions, but much of this effort in the past has focused on the dorsolateral prefrontal cortex sector. Here we will review findings that address decision-making and its link to the ventromedial prefrontal cortex. SUMMARY: Decision-making impairments as encountered in neurological and psychiatric patients are costly in terms of individual human suffering and in financial terms. In addition to its obvious value in advancing fundamental knowledge in neuroscience, understanding the neural mechanisms of decision-making is likely to have important practical consequences, including the understanding and management of neuropsychiatric disorders such as addiction, as well as the management of a considerable number of elderly people suffering from a decline in cognitive functions critical for decision-making, in spite of relatively intact memory and general intellect, which impact real-life matters that are important to themselves and their family.

Brain Injuries↗

PubMed2005

Investment behavior and the negative side of emotion.

Can dysfunction in neural systems subserving emotion lead, under certain circumstances, to more advantageous decisions? To answer this question, we investigated how normal participants, patients with stable focal lesions in brain regions related to emotion (target patients), and patients with stable focal lesions in brain regions unrelated to emotion (control patients) made 20 rounds of investment decisions. Target patients made more advantageous decisions and ultimately earned more money from their investments than the normal participants and control patients. When normal participants and control patients either won or lost money on an investment round, they adopted a conservative strategy and became more reluctant to invest on the subsequent round; these results suggest that they were more affected than target patients by the outcomes of decisions made in the previous rounds.

Affect↗

PubMed2005

Cognitive biases toward alcohol-related words and executive deficits in polysubstance abusers with alcoholism.

AIM: To study cognitive biases for alcohol-related cues on executive function tasks involving mental flexibility and response inhibition in polysubstance abusers with alcoholism. DESIGN: The responses to alcohol-related cues of detoxified polysubstance abusers with alcoholism and of non-addicts were compared. SETTING: The University of Iowa City, Iowa, USA. PARTICIPANTS: Thirty detoxified polysubstance abusers with alcoholism (PSA) and 30 healthy non-substance abusers (CONT). MEASUREMENTS: Using the 'Alcohol Shifting Task', a variant of the go/no-go paradigm, we measured the response times and the accuracy of responses to targets and distracters. Sometimes the alcohol-related words were the targets for the 'go' response, with neutral words as distracters, sometimes the reverse. Several shifts in the type of the target occurred during the task. FINDINGS: Relative to CONT, PSA were generally slower to respond to targets, but the group difference was smaller when alcohol-related words were the targets. A signal detection analysis also indicated that relative to CONT, the PSA had more difficulties discriminating between targets and distracters (low d'), and they showed more signs of decision bias (low C), reflecting increased readiness to respond to both targets and distracters. However, these discrimination and inhibition deficits were more pronounced when alcohol-related words were the targets. Furthermore, the weaknesses in RT and C were more pronounced in PSA after shifting the targets from alcohol-related to neutral words, or vice versa. CONCLUSIONS: These results suggest that PSA have cognitive biases towards information related to alcohol, and that these biases, as well as the poor executive functions (lower mental flexibility and response inhibition) revealed in PSA might be responsible for their failure to maintain abstinence.

Adult↗