Differential effects of insular and ventromedial prefrontal cortex lesions on risky decision-making

Diffusion tensor imaging and decision making in cocaine dependence

BACKGROUND

Chronic stimulant abuse is associated with both impairment in decision making and structural abnormalities in brain gray and white matter. Recent data suggest these structural abnormalities may be related to functional impairment in important behavioral processes.

METHODOLOGY/PRINCIPAL FINDINGS

In 15 cocaine-dependent and 18 control subjects, we examined relationships between decision-making performance on the Iowa Gambling Task (IGT) and white matter integrity as measured by diffusion tensor imaging (DTI). Whole brain voxelwise analyses showed that, relative to controls, the cocaine group had lower fractional anisotropy (FA) and higher mean of the second and third eigenvalues (lambda perpendicular) in frontal and parietal white matter regions and the corpus callosum. Cocaine subjects showed worse performance on the IGT, notably over the last 40 trials. Importantly, FA and lambda perpendicular values in these regions showed a significant relationship with IGT performance on the last 40 trials.

CONCLUSIONS

Compromised white matter integrity in cocaine dependence may be related to functional impairments in decision making.

Insular cortex thinning in first episode schizophrenia patients

Overall and regional cortical thinning has been observed at the first break of schizophrenia. Due to the fact that structural abnormalities in the insular cortex have been described in schizophrenia, we investigated insular thickness anomalies in first episode schizophrenia. Participants comprised 118 schizophrenia patients and 83 healthy subjects. Magnetic resonance imaging brain scans (1.5T) were obtained, and images were analyzed by using BRAINS2. The contribution of sociodemographic, cognitive and clinical characterictics was controlled. Schizophrenia patients demonstrated a significant right insular thinning, and a significant group by gender interaction was found for left insular thickness. Post-hoc comparisons revealed that male schizophrenia patients had a significant left insular thinning compared with healthy male subjects. There were no significant associations between insular thickness, the severity of symptoms at baseline and cognitive measurements and premorbid variables. The fact that insular thinning is already present at early phases of the illness and is independent of intervening variables offers evidence for the potential of these changes to be a biological marker of the illness.

Does the medial orbitofrontal cortex have a role in social valuation?

It has been claimed that social behaviour changes after lesions of the ventromedial prefrontal cortex (vmPFC). However, lesions in humans are rarely restricted to a well defined cortical area. Although vmPFC lesions usually include medial orbitofrontal cortex (mOFC), they typically also affect subgenual and/or perigenual anterior cingulate cortex. The purpose of the current study is to investigate the role of mOFC in social valuation and decision-making. We tested four macaque monkeys prior to and after focal lesions of mOFC. Comparison of the animals' pre- and postoperative performance revealed that, unlike lesions of anterior cingulate gyrus (ACCg), lesions of mOFC did not induce alterations in social valuation. MOFC lesions did, however, induce mild impairments in a probabilistic two-choice decision task, which were not seen after ACCg lesions. In summary, the double dissociation between the patterns of impairment suggest that vmPFC involvement in both decision-making and social valuation may be mediated by distinct subregions centred on mOFC and ACCg respectively.

The neural correlates of endowment effect without economic transaction

People always concern about what they have and what they might lose even it is just imaginary property. According to Prospect Theory, the losses might be weighted by subjects higher than gain, which would cause the disparity between the willingness to accept (WTA) and willingness to pay (WTP) compensation in economic valuation. Using functional MRI, we investigated neural correlates of this inconsistent value estimation, known as the endowment effect, during a simple pricing task without economic transaction. Brain activation associated with this price discrepancy was observed in the right inferior frontal gyrus (IFG), where voxel-based morphometry of MRI revealed the positive correlation between gray matter concentration and WTA/WTP ratio. These findings suggest the functional relevance of IFG in WTA/WTP discrepancy for pricing without any actual gain and loss, where an integration of loss aversion-related signals from insula and expected value signals may occur.

Recent research on impulsivity in individuals with drug use and mental health disorders: implications for alcoholism

Alcohol misuse and dependence, and many of its accompanying psychological problems, are associated with heightened levels of impulsivity that both accelerate the development of clinically significant illness and complicate clinical outcome. This article reviews recent developments in our understanding of impulsivity as they relate to brain circuitry that might underlie these comorbid factors, focusing upon the clinical features of substance use (and dependence), bipolar disorder, and pathological gambling. Individuals who are affected by these disorders exhibit problems in several domains of impulsive behavior including deficient response or "motor" control, and the tolerance of prolonged delays prior to larger rewards at the expense of smaller rewards ("delay-discounting"). These populations, like alcoholic dependents, also exhibit impairments in risky decision-making that may reflect dysfunction of monoamine and catecholamine pathways. However, several areas of uncertainty exist including the specificity of impairments across disorders and the relationship between impulse control problems and altered evaluation of reward outcomes underlying observed impairments in action selection.

Reward/Punishment reversal learning in older suicide attempters

OBJECTIVE

Suicide rates are high in old age, and the contribution of cognitive risk factors remains poorly understood. Suicide may be viewed as an outcome of an altered decision process. The authors hypothesized that impairment in reward/punishment-based learning, a component of affective decision making, is associated with attempted suicide in late-life depression. They expected that suicide attempters would discount past reward/punishment history, focusing excessively on the most recent rewards and punishments. The authors further hypothesized that this impairment could be dissociated from executive abilities, such as forward planning.

METHOD

The authors assessed reward/punishment-based learning using the probabilistic reversal learning task in 65 individuals age 60 and older: suicide attempters, suicide ideators, nonsuicidal depressed elderly, and nondepressed comparison subjects. The authors used a reinforcement learning computational model to decompose reward/punishment processing over time. The Stockings of Cambridge test served as a control measure of executive function.

RESULTS

Suicide attempters but not suicide ideators showed impaired probabilistic reversal learning compared to both nonsuicidal depressed elderly and nondepressed comparison subjects, after controlling for effects of education, global cognitive function, and substance use. Model-based analyses revealed that suicide attempters discounted previous history to a higher degree relative to comparison subjects, basing their choice largely on reward/punishment received on the last trial. Groups did not differ in their performance on the Stockings of Cambridge test.

CONCLUSIONS

Older suicide attempters display impaired reward/punishment-based learning. The authors propose a hypothesis that older suicide attempters make overly present-focused decisions, ignoring past experiences. Modification of this "myopia for the past" may have therapeutic potential.

Decision-making during gambling: an integration of cognitive and psychobiological approaches

Gambling is a widespread form of entertainment that may afford unique insights into the interaction between cognition and emotion in human decision-making. It is also a behaviour that can become harmful, and potentially addictive, in a minority of individuals. This article considers the status of two dominant approaches to gambling behaviour. The cognitive approach has identified a number of erroneous beliefs held by gamblers, which cause them to over-estimate their chances of winning. The psychobiological approach has examined case-control differences between groups of pathological gamblers and healthy controls, and has identified dysregulation of brain areas linked to reward and emotion, including the ventromedial prefrontal cortex (vmPFC) and striatum, as well as alterations in dopamine neurotransmission. In integrating these two approaches, recent data are discussed that reveal anomalous recruitment of the brain reward system (including the vmPFC and ventral striatum) during two common cognitive distortions in gambling games: the near-miss effect and the effect of personal control. In games of chance, near-misses and the presence of control have no objective influence on the likelihood of winning. These manipulations appear to harness a reward system that evolved to learn skill-oriented behaviours, and by modulating activity in this system, these cognitive distortions may promote continued, and potentially excessive, gambling.

The Iowa Gambling Task in fMRI images

The Iowa Gambling Task (IGT) is a sensitive test for the detection of decision-making impairments in several neurological and psychiatric populations. Very few studies have employed the IGT in functional magnetic resonance imaging (fMRI) investigations, in part, because the task is cognitively complex. Here we report a method for exploring brain activity using fMRI during performance of the IGT. Decision-making during the IGT was associated with activity in several brain regions in a group of healthy individuals. The activated regions were consistent with the neural circuitry hypothesized to underlie somatic marker activation and decision-making. Specifically, a neural circuitry involving the dorsolateral prefrontal cortex (for working memory), the insula and posterior cingulate cortex (for representations of emotional states), the mesial orbitofrontal and ventromedial prefrontal cortex (for coupling the two previous processes), the ventral striatum and anterior cingulate/SMA (supplementary motor area) for implementing behavioral decisions was engaged. These results have implications for using the IGT to study abnormal mechanisms of decision making in a variety of clinical populations.

Frontal cerebral vulnerability and executive deficits from raised intracranial pressure in child traumatic brain injury

In severe pediatric traumatic brain injury (TBI), a common focus of treatment is raised intracranial pressure (ICP). The aim of this investigation was to test whether raised ICP is associated with later prefrontal executive deficits and regional brain tissue loss, consistent with an anterior vascular compartment syndrome. Thirty-three participants were assigned to one of two severe TBI groups based on whether or not they had increased ICP complicating their critical illness. At follow-up (average 3.9 years), the participants underwent magnetic resonance imaging and a battery of neuropsychological testing focused on prefrontal function. The ICP group had white matter loss that was diffuse as well as regional in the corpus callosum, periventricular tissue, and frontal region. Loss of gray matter in the ICP group was more regionally specific, with bilateral loss in the caudate nuclei and frontal regions, including the right dorsolateral region, right supplementary motor area, and the left orbitofrontal cortex. Both groups had normal intelligence quotients (IQs), but the ICP group showed long-term deficits on various measures of attention and executive function such as working memory, decision-making, and impulsivity. These findings suggest that raised ICP leads to diffuse brain injury and a predilection to hypoperfusion in, at least, the distribution of the anterior cerebral artery. Furthermore, since voxel-based morphometry (VBM) and measures of attention and executive function are sensitive to the phenomenon of raised ICP, we consider that these techniques warrant inclusion in trials assessing ICP-directed therapy.

Alterations of decision making and underlying neural correlates after resection of a mediofrontal cortical dysplasia: A single case study

We investigated the impact of a congenital prefrontal lesion and its resection on decision making under risk and under ambiguity in a patient with right mediofrontal cortical dysplasia. Both kinds of decision making are normally associated with the medial prefrontal cortex. We additionally studied pre- and postsurgical fMRI activations when processing information relevant for risky decision making. Results indicate selective impairments of ambiguous decision making pre- and postsurgically. Decision making under risk was intact. In contrast to healthy subjects the patient exhibited no activation within the dysplastic anterior cingulate cortex but left-sided orbitofrontal activation on the fMRI task suggesting early reorganization processes.

Neurocircuitry of addiction

Drug addiction is a chronically relapsing disorder that has been characterized by (1) compulsion to seek and take the drug, (2) loss of control in limiting intake, and (3) emergence of a negative emotional state (eg, dysphoria, anxiety, irritability) reflecting a motivational withdrawal syndrome when access to the drug is prevented. Drug addiction has been conceptualized as a disorder that involves elements of both impulsivity and compulsivity that yield a composite addiction cycle composed of three stages: 'binge/intoxication', 'withdrawal/negative affect', and 'preoccupation/anticipation' (craving). Animal and human imaging studies have revealed discrete circuits that mediate the three stages of the addiction cycle with key elements of the ventral tegmental area and ventral striatum as a focal point for the binge/intoxication stage, a key role for the extended amygdala in the withdrawal/negative affect stage, and a key role in the preoccupation/anticipation stage for a widely distributed network involving the orbitofrontal cortex-dorsal striatum, prefrontal cortex, basolateral amygdala, hippocampus, and insula involved in craving and the cingulate gyrus, dorsolateral prefrontal, and inferior frontal cortices in disrupted inhibitory control. The transition to addiction involves neuroplasticity in all of these structures that may begin with changes in the mesolimbic dopamine system and a cascade of neuroadaptations from the ventral striatum to dorsal striatum and orbitofrontal cortex and eventually dysregulation of the prefrontal cortex, cingulate gyrus, and extended amygdala. The delineation of the neurocircuitry of the evolving stages of the addiction syndrome forms a heuristic basis for the search for the molecular, genetic, and neuropharmacological neuroadaptations that are key to vulnerability for developing and maintaining addiction.

Region-specific alteration in brain glutamate: possible relationship to risk-taking behavior

Risk-taking behaviors involve increased motor activity and reduced anxiety in humans. Total sleep deprivation (SD) in animals produces a similar change in motor and fear behaviors. Investigators studied region-specific brain levels of glutamate in rats after TSD, an animal model of risk-taking behavior. We investigated the effects of sleep deprivation on these behaviors and associated levels of brain glutamate. Compared to the controls, the sleep-deprived rats spent a significantly greater percentage of time in the open arms of the elevated plus maze (EPM), demonstrating reduced fear-like and increased risk-taking behaviors. Additionally, sleep deprivation was associated with a significant increase in glutamate levels in the hippocampus and thalamus. An inverse relationship between glutamate in the medial prefrontal cortex and risk taking in the EPM and a positive association between the ratio of glutamate in the hippocampus to medial prefrontal cortex and risk taking was revealed. The role of sleep deprivation-induced changes in brain glutamate and its relationship to anxiety, fear, and posttraumatic stress disorder (PTSD) is discussed.

Prefrontal cortical contribution to risk-based decision making

Damage to various regions of the prefrontal cortex (PFC) impairs decision making involving evaluations about risks and rewards. However, the specific contributions that different PFC subregions make to risk-based decision making are unclear. We investigated the effects of reversible inactivation of 4 subregions of the rat PFC (prelimbic medial PFC, orbitofrontal cortex [OFC], anterior cingulate, and insular cortex) on probabilistic (or risk) discounting. Rats were well trained to choose between either a "Small/Certain" lever that always delivered 1 food pellet, or another, "Large/Risky" lever, which delivered 4 pellets, but the probability of receiving reward decreased across 4 trial blocks (100%, 50%, 25%, and 12.5%). Infusions of gama-aminobutyric acid agonists muscimol/baclofen into the medial PFC increased risky choice. However, similar medial PFC inactivations decreased risky choice when the Large/Risky reward probability increased over a session. OFC inactivation increased response latencies in the latter trial blocks without affecting choice. Anterior cingulate or insular inactivations were without effect. The effects of prelimbic inactivations were not attributable to disruptions in response flexibility or judgments about the relative value of probabilistic rewards. Thus, the prelimbic, but not other PFC regions, plays a critical role in risk discounting, integrating information about changing reward probabilities to update value representations that facilitate efficient decision making.

Temporal decision-making: insights from cognitive neuroscience

Decisions frequently have consequences that play out over time and these temporal factors can exert strong influences on behavior. For example, decision-makers exhibit delay discounting, behaving as though immediately consumable goods are more valuable than those available only after some delay. With the use of functional magnetic resonance imaging, we are now beginning to characterize the physiological bases of such behavior in humans and to link work on this topic from neuroscience, psychology, and economics. Here we review recent neurocognitive investigations of temporal decision-making and outline the theoretical picture that is beginning to take shape. Taken as a whole, this body of work illustrates the progress made in understanding temporal choice behavior. However, we also note several questions that remain unresolved and areas where future work is needed.

Decision-making impairments in women with binge eating disorder

Even though eating is frequently driven by overindulgence and reward rather than by energy balance, few studies so far have analyzed decision-making processes and disturbances in feedback processing in women with binge eating disorder (BED). In an experimental study, 17 women with BED (DSM-IV) and 18 overweight healthy controls (HC) were compared in the game of dice task (GDT). This task assesses decision-making under risk with explicit rules for gains and losses. Additionally, differences in dispositional activation of the behavior inhibition and behavior approach system as well as cognitive flexibility were measured. Main results revealed that women with BED make risky decisions significantly more often than HC. Moreover, they show impaired capacities to advantageously utilize feedback processing. Even though these deficits were not related to disease-specific variables, they may be important for the daily decision-making behavior of women with BED, thus being relevant as a maintenance factor for the disorder.

Taking a gamble or playing by the rules: dissociable prefrontal systems implicated in probabilistic versus deterministic rule-based decisions

A decision may be difficult because complex information processing is required to evaluate choices according to deterministic decision rules and/or because it is not certain which choice will lead to the best outcome in a probabilistic context. Factors that tax decision making such as decision rule complexity and low decision certainty should be disambiguated for a more complete understanding of the decision making process. Previous studies have examined the brain regions that are modulated by decision rule complexity or by decision certainty but have not examined these factors together in the context of a single task or study. In the present functional magnetic resonance imaging study, both decision rule complexity and decision certainty were varied in comparable decision tasks. Further, the level of certainty about which choice to make (choice certainty) was varied separately from certainty about the final outcome resulting from a choice (outcome certainty). Lateral prefrontal cortex, dorsal anterior cingulate cortex, and bilateral anterior insula were modulated by decision rule complexity. Anterior insula was engaged more strongly by low than high choice certainty decisions, whereas ventromedial prefrontal cortex showed the opposite pattern. These regions showed no effect of the independent manipulation of outcome certainty. The results disambiguate the influence of decision rule complexity, choice certainty, and outcome certainty on activity in diverse brain regions that have been implicated in decision making. Lateral prefrontal cortex plays a key role in implementing deterministic decision rules, ventromedial prefrontal cortex in probabilistic rules, and anterior insula in both.

Decision-making in Parkinson's disease patients with and without pathological gambling

BACKGROUND AND PURPOSE

Pathological gambling (PG) in Parkinson's disease (PD) is a frequent impulse control disorder associated mainly with dopamine replacement therapy. As impairments in decision-making were described independently in PG and PD, the objective of this study was to assess decision-making processes in PD patients with and without PG.

METHODS

Seven PD patients with PG and 13 age, sex, education and disease severity matched PD patients without gambling behavior were enrolled in the study. All patients were assessed with a comprehensive neuropsychiatric and cognitive evaluation, including tasks used to assess decision-making abilities under ambiguous or risky situations, like the Iowa Gambling Task (IGT), the Game of Dice Task and the Investment Task.

RESULTS

Compared to PD patients without gambling behavior, those with PG obtained poorer scores in the IGT and in a rating scale of social behavior, but not in other decision-making and cognitive tasks.

CONCLUSIONS

Low performance in decision-making under ambiguity and abnormal social behavior distinguished PD patients with PG from those without this disorder. Dopamine replacement therapy may induce dysfunction of the ventromedial prefrontal cortex and amygdala-ventral striatum system, thus increasing the risk for developing PG.

Decision-making under risk: an fMRI study

Recent research has focused on decision-making under risk and its neural bases. Two kinds of bad decisions under risk may be defined: too risky decisions and too cautious decisions. Here we show that suboptimal decisions of both kinds lead to increased activity in the anterior cingulate cortex in a Blackjack gambling task. Moreover, this increased activity is related to the avoidance of the negatively evaluated decision under risk. These findings complement other results suggesting an important role of the dorsal anterior cingulate cortex in reward-based decision-making and conflict resolution.

Balancing risk and reward: a rat model of risky decision making

We developed a behavioral task in rats to assess the influence of risk of punishment on decision making. Male Long-Evans rats were given choices between pressing a lever to obtain a small, 'safe' food reward and a large food reward associated with risk of punishment (footshock). Each test session consisted of 5 blocks of 10 choice trials, with punishment risk increasing with each consecutive block (0, 25, 50, 75, 100%). Preference for the large, 'risky' reward declined with both increased probability and increased magnitude of punishment, and reward choice was not affected by the level of satiation or the order of risk presentation. Performance in this risky decision-making task was correlated with the degree to which the rats discounted the value of probabilistic rewards, but not delayed rewards. Finally, the acute effects of different doses of amphetamine and cocaine on risky decision making were assessed. Systemic amphetamine administration caused a dose-dependent decrease in choice of the large risky reward (ie, it made rats more risk averse). Cocaine did not cause a shift in reward choice, but instead impaired the rats' sensitivity to changes in punishment risk. These results should prove useful for investigating neuropsychiatric disorders in which risk taking is a prominent feature, such as attention deficit/hyperactivity disorder and addiction.

A common role of insula in feelings, empathy and uncertainty

Although accumulating evidence highlights a crucial role of the insular cortex in feelings, empathy and processing uncertainty in the context of decision making, neuroscientific models of affective learning and decision making have mostly focused on structures such as the amygdala and the striatum. Here, we propose a unifying model in which insula cortex supports different levels of representation of current and predictive states allowing for error-based learning of both feeling states and uncertainty. This information is then integrated in a general subjective feeling state which is modulated by individual preferences such as risk aversion and contextual appraisal. Such mechanisms could facilitate affective learning and regulation of body homeostasis, and could also guide decision making in complex and uncertain environments.

Acute stress increases sex differences in risk seeking in the balloon analogue risk task

BACKGROUND

Decisions involving risk often must be made under stressful circumstances. Research on behavioral and brain differences in stress responses suggest that stress might have different effects on risk taking in males and females.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, participants played a computer game designed to measure risk taking (the Balloon Analogue Risk Task) fifteen minutes after completing a stress challenge or control task. Stress increased risk taking among men but decreased it among women.

CONCLUSIONS/SIGNIFICANCE

Acute stress amplifies sex differences in risk seeking; making women more risk avoidant and men more risk seeking. Evolutionary principles may explain these stress-induced sex differences in risk taking behavior.

Problem gamblers share deficits in impulsive decision-making with alcohol-dependent individuals

AIMS

Problem gambling has been proposed to represent a 'behavioural addiction' that may provide key insights into vulnerability mechanisms underlying addiction in brains that are not affected by the damaging effects of drugs. Our aim was to investigate the neurocognitive profile of problem gambling in comparison with alcohol dependence. We reasoned that shared deficits across the two conditions may reflect underlying vulnerability mechanisms, whereas impairments specific to alcohol dependence may reflect cumulative effects of alcohol consumption.

DESIGN

Cross-sectional study.

SETTING

Out-patient addiction treatment centres and university behavioural testing facilities.

PARTICIPANTS

A naturalistic sample of 21 male problem and pathological gamblers, 21 male alcohol-dependent out-patients and 21 healthy male control participants.

MEASUREMENTS

Neurocognitive battery assessing decision-making, impulsivity and working memory.

FINDINGS

The problem gamblers and alcohol-dependent groups displayed impairments in risky decision-making and cognitive impulsivity relative to controls. Working memory deficits and slowed deliberation times were specific to the alcohol-dependent group.

CONCLUSIONS

Gambling and alcohol-dependent groups shared deficits in tasks linked to ventral prefrontal cortical dysfunction. Tasks loading on dorsolateral prefrontal cortex were selectively impaired in the alcohol-dependent group, presumably as a consequence of long-term alcohol use.

On the role of dopamine replacement therapy in decision-making, working memory, and reward in Parkinson's disease: does the therapy-dose matter?

BACKGROUND

Dopaminergic therapy proved to ameliorate motor deficits in Parkinson's disease but its effects on behavior and cognition vary according to factors that include, among others, the evolution of the disease and the nature of the task that is tested. This study addressed the question of whether, in moderate to advanced Parkinson's disease (PD) with motor fluctuations, changes in decision-making and sensitivity to reward occur and to what extent dopaminergic therapy plays a role.

METHODS

Fifteen PD patients (On and Off medication) and thirteen healthy controls were compared on two different tasks which analyzed decision-making processes (the Cambridge Gamble Task, CGT) and working memory abilities with and without the prospect of reward (modified N-back task).

RESULTS

We found that the PD patients were unable to choose an optimal betting strategy and were impulsive in their choices relative to the control group. Further, a detrimental dose-dependent effect of dopaminergic therapy was detected, meaning that those patients who were taking higher doses of therapy were more impulsive in selecting bets and more impaired in making probabilistic choices. Such a dose-dependent effect was not found on the N-back task. However, the results of the PD group in this task supported indirect evidence of the amelioration of performance in rewarded conditions.

CONCLUSION

Our results suggest that the detrimental effects of dopaminergic therapy may be dose-related and that the interaction between monetary reward and dopaminergic therapy can affect and improve some cognitive abilities, such as working memory.

General mechanisms for making decisions?

It has been suggested that many aspects of reward-guided behaviour can be understood within the framework of a computational account of decision making. The account emphasises representation of expectations about decision outcomes and the revision of future expectations in the light of the prediction error-the discrepancy between the actual outcome and prior expectation. Frontal cortex and striatum are implicated in such processes in humans, monkeys, and rats suggesting they are ubiquitous and found in many species. Disagreement remains over the exact contribution made by each brain region. A growing body of work even suggests analogous processes may account for behaviour outside the domain of reward-guided decision making, for example, when people and animals learn about visual and social environments.

Gambling near-misses enhance motivation to gamble and recruit win-related brain circuitry

"Near-miss" events, where unsuccessful outcomes are proximal to the jackpot, increase gambling propensity and may be associated with the addictiveness of gambling, but little is known about the neurocognitive mechanisms that underlie their potency. Using a simplified slot machine task, we measured behavioral and neural responses to gambling outcomes. Compared to "full-misses," near-misses were experienced as less pleasant, but increased desire to play. This effect was restricted to trials where the subject had personal control over arranging their gamble. Near-miss outcomes recruited striatal and insula circuitry that also responded to monetary wins; in addition, near-miss-related activity in the rostral anterior cingulate cortex varied as a function of personal control. Insula activity to near-misses correlated with self-report ratings as well as a questionnaire measure of gambling propensity. These data indicate that near-misses invigorate gambling through the anomalous recruitment of reward circuitry, despite the objective lack of monetary reinforcement on these trials.

Thinking like a trader selectively reduces individuals' loss aversion

Research on emotion regulation has focused upon observers' ability to regulate their emotional reaction to stimuli such as affective pictures, but many other aspects of our affective experience are also potentially amenable to intentional cognitive regulation. In the domain of decision-making, recent work has demonstrated a role for emotions in choice, although such work has generally remained agnostic about the specific role of emotion. Combining psychologically-derived cognitive strategies, physiological measurements of arousal, and an economic model of behavior, this study examined changes in choices (specifically, loss aversion) and physiological correlates of behavior as the result of an intentional cognitive regulation strategy. Participants were on average more aroused per dollar to losses relative to gains, as measured with skin conductance response, and the difference in arousal to losses versus gains correlated with behavioral loss aversion across subjects. These results suggest a specific role for arousal responses in loss aversion. Most importantly, the intentional cognitive regulation strategy, which emphasized "perspective-taking," uniquely reduced both behavioral loss aversion and arousal to losses relative to gains, largely by influencing arousal to losses. Our results confirm previous research demonstrating loss aversion while providing new evidence characterizing individual differences and arousal correlates and illustrating the effectiveness of intentional regulation strategies in reducing loss aversion both behaviorally and physiologically.

Dopaminergic modulation of risk-based decision making

Psychopharmacological studies have implicated the mesolimbic dopamine (DA) system in the mediation of cost/benefit evaluations about delay or effort-related costs associated with larger rewards. However, the role of DA in risk-based decision making remains relatively unexplored. The present study investigated the effects of systemic manipulations of DA transmission on risky choice using a probabilistic discounting task. Over discrete trials, rats chose between two levers; a press on the 'small/certain' lever always delivered one reward pellet, whereas a press on the other, 'large/risky' lever delivered four pellets, but the probability of receiving reward decreased across the four trial blocks (100, 50, 25, 12.5%). In separate groups of well-trained rats we assessed the effects of the DA releaser amphetamine, as well as receptor selective agonists and antagonists. Amphetamine consistently increased preference for the large/risky lever; an effect that was blocked or attenuated by co-administration of either D(1) (SCH23390) or D(2) (eticlopride) receptor antagonists. Blockade of either of these receptors alone induced risk aversion. Conversely, stimulation of D(1) (SKF81297) or D(2) (bromocriptine) receptors also increased risky choice. In contrast, activation of D(3) receptors with PD128,907 reduced choice of the large/risky lever. Likewise, D(3) antagonism with nafadotride potentiated the amphetamine-induced increase in risky choice. Blockade or stimulation of D(4) receptors did not reliably alter behavior. These findings indicate that DA has a critical role in mediating risk-based decision making, with increased activation of D(1) and D(2) receptors biasing choice toward larger, probabilistic rewards, whereas D(3) receptors appear to exert opposing effects on this form of decision making.

The morphology of supragranular pyramidal neurons in the human insular cortex: a quantitative Golgi study

Although the primate insular cortex has been studied extensively, a comprehensive investigation of its neuronal morphology has yet to be completed. To that end, neurons from 20 human subjects (10 males and 10 females; N = 600) were selected from the secondary gyrus brevis, precentral gyrus, and postcentral gyrus of the left insula. The secondary gyrus brevis was generally more complex in terms of dendritic/spine extent than either the precentral or postcentral insular gyri, which is consistent with the posterior-anterior gradient of dendritic complexity observed in other cortical regions. The male insula had longer, spinier dendrites than the female insula, potentially reflecting sex differences in interoception. In comparing the current insular data with regional dendritic data quantified from other Brodmann's areas (BAs), insular total dendritic length (TDL) was less than the TDL of high integration cortices (BA6beta, 10, 11, 39), but greater than the TDL of low integration cortices (BA3-1-2, 4, 22, 44). Insular dendritic spine number was significantly greater than both low and high integration regions. Overall, the insula had spinier, but shorter neurons than did high integration cortices, and thus may represent a specialized type of heteromodal cortex, one that integrates crude multisensory information crucial to interoceptive processes.

Parsing pain perception between nociceptive representation and magnitude estimation

Assessing the size of objects rapidly and accurately clearly has survival value. A central multisensory module for subjective magnitude assessment is therefore highly likely, suggested by psychophysical studies, and proposed on theoretical grounds. Given that pain perception is fundamentally an assessment of stimulus intensity, it must necessarily engage such a central module. Accordingly, we compared functional magnetic resonance imaging (fMRI) activity of pain magnitude ratings to matched visual magnitude ratings in 14 subjects. We show that brain activations segregate into two groups, one preferentially activated for pain and another equally activated for both visual and pain magnitude ratings. The properties of regions in the first group were consistent with encoding nociception, whereas those in the second group with attention and task control. Insular cortex responses similarly segregated to a pain-specific area and an area (extending to the lateral prefrontal cortex) conjointly representing perceived magnitudes for pain and vision. These two insular areas were differentiated by their relationship to task variance, ability to encode perceived magnitudes for each stimulus epoch, temporal delay differences, and brain intrinsic functional connectivity. In a second group of subjects (n=11) we contrasted diffusion tensor imaging-based white matter connectivity for these two insular areas and observed anatomical connectivity closely corresponding to the functional connectivity identified with fMRI. These results demonstrate that pain perception is due to the transformation of nociceptive representation into subjective magnitude assessment within the insula. Moreover, we argue that we have identified a multisensory cortical area for "how much" complementary and analogous to the "where" and "what" as described for central visual processing.

Review. The neurobiology of pathological gambling and drug addiction: an overview and new findings

Gambling is a prevalent recreational behaviour. Approximately 5% of adults have been estimated to experience problems with gambling. The most severe form of gambling, pathological gambling (PG), is recognized as a mental health condition. Two alternate non-mutually exclusive conceptualizations of PG have considered it as an obsessive-compulsive spectrum disorder and a 'behavioural' addiction. The most appropriate conceptualization of PG has important theoretical and practical implications. Data suggest a closer relationship between PG and substance use disorders than exists between PG and obsessive-compulsive disorder. This paper will review data on the neurobiology of PG, consider its conceptualization as a behavioural addiction, discuss impulsivity as an underlying construct, and present new brain imaging findings investigating the neural correlates of craving states in PG as compared to those in cocaine dependence. Implications for prevention and treatment strategies will be discussed.

Cognitive control mechanisms, emotion and memory: a neural perspective with implications for psychopathology

In this paper we provide a focused review of the literature examining neural mechanisms involved in cognitive control over memory processes that can influence, and in turn are influenced by, emotional processes. The review is divided into two parts, the first focusing on working memory and the second on long-term memory. With regard to working memory, we discuss the neural bases of (1) control mechanisms that can select against distracting emotional information, (2) mechanisms that can regulate emotional reactions or responses, (3) how mood state influences cognitive control, and (4) individual differences in control mechanisms. For long-term memory, we briefly review (1) the neural substrates of emotional memory, (2) the cognitive and neural mechanisms that are involved in controlling emotional memories and (3) how these systems are altered in post-traumatic stress disorder. Finally, we consider tentative generalizations that can be drawn from this relatively unexplored conjunction of research endeavors.

The effects of methylphenidate on decision making in attention-deficit/hyperactivity disorder

BACKGROUND

Children with attention-deficit/hyperactivity disorder (ADHD) frequently display poor judgment and risk taking in their everyday behavior, but there are little empirical data on decision-making cognition in this disorder. The objectives of the study were to assess the effects of stimulant medication on decision making in ADHD and compare performance on the Cambridge Gamble Task between boys with and without ADHD.

METHODS

Twenty-one boys (aged 7-13) diagnosed with ADHD underwent a double-blind, placebo-controlled trial of methylphenidate (.5 mg/kg) during which they performed the Cambridge Gamble Task (CGT). A healthy age-matched control group was tested on two occasions off drug.

RESULTS

The ADHD group bet more conservatively on the methylphenidate session than on the placebo session. In comparison with healthy control subjects, the ADHD group made more poor decisions, placed their bets more impulsively, and adjusted their bets less according to the chances of winning. Poor decision making was correlated with parent-reported symptoms and disruptive behavior in the ADHD group.

CONCLUSIONS

Methylphenidate reduced risk-prone betting behavior on the CGT. Compared with control subjects, children with ADHD display a number of decision-making deficits on the task, and the measure of rational decision making may serve as an ecologically valid neuropsychological marker of impairment.