Antoine Bechara

The ability to decide advantageously declines prematurely in some normal older persons

The prefrontal region of the brain, including the ventromedial sector which supports reasoning and decision-making, may undergo disproportionate aging in some older persons, but the empirical evidence is decidedly mixed. To help resolve this, we tested 80 neurologically and psychiatrically healthy Younger (aged 26-55) and Older (aged 56-85) adults on a Gambling Task, which provides a close analog to real-world decision-making by factoring in reward, punishment, and unpredictability, yielding a sensitive index of ventromedial prefrontal function. A subset of the Older group manifested a decision-making impairment on the Gambling Task, in spite of otherwise intact cognitive functioning. This finding raises the possibility of disproportionate aging of the ventromedial prefrontal cortex in these individuals. Our finding has important societal and public policy implications (e.g., choosing medical care, allocating personal wealth), and may also help explain why many older individuals are targeted by and susceptible to fraudulent advertising.

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.

Right ventromedial prefrontal cortex: a neuroanatomical correlate of impulse control in boys

Emerging data on the neural mechanisms of impulse control highlight brain regions involved in emotion and decision making, including the ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC) and amygdala. Variation in the development of these regions may influence ones propensity for impulsivity and, by extension, ones vulnerability to disorders involving low impulse control (e.g. substance abuse). Here we test the hypothesis that lower impulse control is associated with structural differences in these regions, particularly on the right side, in 61 normal healthy boys aged 7-17. We assessed parent- and teacher-reported behavioral ratings of impulse control (motor impulsivity and non-planning behavior) in relation to vmPFC, ACC and amygdala volume, measured using structural magnetic resonance imaging and FreeSurfer. A regression analysis showed that the right vmPFC was a significant predictor of impulse control ratings. Follow-up tests showed (i) a significant correlation between low impulse control and decreased right vmPFC volume, especially the medial sector of the vmPFC and (ii) significantly lower right vmPFC volume in a subgroup of 20 impulsive boys relative to 20 non-impulsive boys. These results are consistent with the notion that right vmPFC provides a neuroanatomical correlate of the normal variance in impulse control observed in boys.

Neuropsychological Approaches to Reasoning and Decision-Making

How do people reason and decide? Patients with damage to the ventromedial frontal cortex help answer this question, since their lesion renders their choices in the real world irrational, i.e., not in their best interest. Our approach was to describe dysfunction in real life circumstances and then to attempt to analyze the components of this dysfunction with controlled laboratory manipulations, employing psychophysiological and neuropsychological methods. The results we report in this paper suggest that this group of patients is defective in an essential and specific component of reasoning, the ability to guide choice by feeling.

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.

Impaired perception of self-motion (heading) in abstinent ecstasy and marijuana users.

RationaleIllicit drug use can increase driver crash risk due to loss of control over vehicle trajectory. This study asks, does recreational use of ±3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) and tetrahydrocannabinol (THC; marijuana) impair cognitive processes that help direct our safe movement through the world?ObjectiveThis study assesses the residual effects of combined MDMA/THC use, and of THC use alone, upon perceived trajectory of travel.MethodsPerception of self-motion, or heading, from optical flow patterns was assessed using stimuli comprising random dot ground planes presented at three different densities and eight heading angles (1, 2, 4 and 8° to the left or right). On each trial, subjects reported if direction of travel was to the left or the right.ResultsResults showed impairments in both drug groups, with the MDMA/THC group performing the worst.ConclusionsThe finding that these psychoactive agents adversely affect heading perception, even in recently abstinent users, raises potential concerns about MDMA use and driving ability.

Does vivid emotional imagery depend on body signals

The recall and re-experiencing of a personal emotional event (emotional imagery) are thought to evoke neural activity in the central nervous system that can affect the physiology of bodily states. It has been proposed that the more active the neural systems previously engaged in the emotional experience, and the more active the bodily state associated with that experience, the more vivid the emotional imagery is. The sympathetic nervous system (SNS) and the gastrointestinal system (GI) are engaged in emotional reactions. On this basis, we hypothesized that vivid emotional imagery would be accompanied by strong increases in gastrointestinal and sympathetic nervous system activity. To test this hypothesis, 17 healthy participants performed emotional imagery of strong autobiographical memories involving various emotional states (happy, fear, disgust, sadness, anger). SNS and GI changes, measured by skin conductance and electrogastrogram, respectively, correlated positively with subjective ratings of arousal during the imagery. However, the SNS changes did not correlate with ratings of emotional imagery vividness, and even more intriguingly, the GI changes correlated strongly and negatively with vividness ratings. To account for these findings, we propose that in highly vivid imagery experience, the central nervous system is simulating the whole emotional experience strongly, and bodily information plays a lesser role. In low vivid imagery experience, the central nervous system is not simulating very strongly the emotional experience, and information coming from the body (including the GI system) plays a greater role. This interpretation is set forth in the context of Damasios [Damasio, A., (1999) The feeling of what happens: body and emotion in the making of consciousness, Orlando, Fl, Harcourt.] theoretical framework, which predicts such a dissociation between a body loop and an as if body loop for the experiencing and re-experiencing of emotions and feelings.

Simulated Driving and Attention of Repeat Users of MDMA and THC Compared with THC Users and Non-Drug-Using Controls

The aim of the study is to assess if cognitive impairments in abstinent users of methylenedioxymethamphetamine (MDMA) are due to repeated use of MDMA or concurrent drugs of abuse and how these impairments interfere with key activities of daily life such as automobile driving. Simulated driving performance and attention of 12 users of MDMA and marijuana [tetrahydrocannabinol (THC)] (MDMA/THC), 15 THC users, and 15 non-drug-using, age-matched controls were compared. THC users mean speed reduction in response to passing a car parked on the shoulder of the road was 7 mph (11.3 km/h) less than that of controls. Compared with non-drug-using controls, the MDMA/THC users were less able to mitigate the effects of an illegal intersection incursion by another vehicle and entered the collision at a higher speed (42 versus 26 mph). In real life, this 16-mph (26-km/h) difference would increase the likelihood of injuring parties in both colliding vehicles. Processing speed and attention did not differ between groups; t...