Brooks King-Casas

The rupture and repair of cooperation in borderline personality disorder.

To sustain or repair cooperation during a social exchange, adaptive creatures must understand social gestures and the consequences when shared expectations about fair exchange are violated by accident or intent. We recruited 55 individuals afflicted with borderline personality disorder (BPD) to play a multiround economic exchange game with healthy partners. Behaviorally, individuals with BPD showed a profound incapacity to maintain cooperation, and were impaired in their ability to repair broken cooperation on the basis of a quantitative measure of coaxing. Neurally, activity in the anterior insula, a region known to respond to norm violations across affective, interoceptive, economic, and social dimensions, strongly differentiated healthy participants from individuals with BPD. Healthy subjects showed a strong linear relation between anterior insula response and both magnitude of monetary offer received from their partner (input) and the amount of money repaid to their partner (output). In stark contrast, activity in the anterior insula of BPD participants was related only to the magnitude of repayment sent back to their partner (output), not to the magnitude of offers received (input). These neural and behavioral data suggest that norms used in perception of social gestures are pathologically perturbed or missing altogether among individuals with BPD. This game-theoretic approach to psychopathology may open doors to new ways of characterizing and studying a range of mental illnesses.

Neuroimaging after mild traumatic brain injury: review and meta-analysis.

This paper broadly reviews the study of mild traumatic brain injury (mTBI), across the spectrum of neuroimaging modalities. Among the range of imaging methods, however, magnetic resonance imaging (MRI) is unique in its applicability to studying both structure and function. Thus we additionally performed meta-analyses of MRI results to examine 1) the issue of anatomical variability and consistency for functional MRI (fMRI) findings, 2) the analogous issue of anatomical consistency for white-matter findings, and 3) the importance of accounting for the time post injury in diffusion weighted imaging reports. As we discuss, the human neuroimaging literature consists of both small and large studies spanning acute to chronic time points that have examined both structural and functional changes with mTBI, using virtually every available medical imaging modality. Two key commonalities have been used across the majority of imaging studies. The first is the comparison between mTBI and control populations. The second is the attempt to link imaging results with neuropsychological assessments. Our fMRI meta-analysis demonstrates a frontal vulnerability to mTBI, demonstrated by decreased signal in prefrontal cortex compared to controls. This vulnerability is further highlighted by examining the frequency of reported mTBI white matter anisotropy, in which we show a strong anterior-to-posterior gradient (with anterior regions being more frequently reported in mTBI). Our final DTI meta-analysis examines a debated topic arising from inconsistent anisotropy findings across studies. Our results support the hypothesis that acute mTBI is associated with elevated anisotropy values and chronic mTBI complaints are correlated with depressed anisotropy. Thus, this review and set of meta-analyses demonstrate several important points about the ongoing use of neuroimaging to understand the functional and structural changes that occur throughout the time course of mTBI recovery. Based on the complexity of mTBI, however, much more work in this area is required to characterize injury mechanisms and recovery factors and to achieve clinically-relevant capabilities for diagnosis.

Agent-Specific Responses in the Cingulate Cortex During Economic Exchanges

Interactions with other responsive agents lie at the core of all social exchange. During a social exchange with a partner, one fundamental variable that must be computed correctly is who gets credit for a shared outcome; this assignment is crucial for deciding on an optimal level of cooperation that avoids simple exploitation. We carried out an iterated, two-person economic exchange and made simultaneous hemodynamic measurements from each players brain. These joint measurements revealed agent-specific responses in the social domain (“me” and “not me”) arranged in a systematic spatial pattern along the cingulate cortex. This systematic response pattern did not depend on metrical aspects of the exchange, and it disappeared completely in the absence of a responding partner.

The neurobiology of social decision-making

Humans live in highly complex social environments and some of our most important decisions are made in the context of social interactions. Research that probes the neural basis of decision-making in the context of social interactions combines behavioral paradigms from game theory with a variety of methods from neuroscience. The neural correlates of decision making in reciprocal exchange and bargaining games have been probed with functional neuroimaging, transcranial magnetic stimulation, and pharmacological manipulations. These studies have begun to elucidate a set of brain regions and neurotransmitter systems involved in decision-making in social interactions.

Understanding Interpersonal Function in Psychiatric Illness Through Multiplayer Economic Games

Interpersonal factors play significant roles in the onset, maintenance, and remission of psychiatric conditions. In the current major diagnostic classification systems for psychiatric disorders, some conditions are defined by the presence of impairments in social interaction or maintaining interpersonal relationships; these include autism, social phobia, and the personality disorders. Other psychopathologies confer significant difficulties in the social domain, including major depression, posttraumatic stress disorder, and psychotic disorders. Still other mental health conditions, including substance abuse and eating disorders, seem to be exacerbated or triggered in part by the influence of social peers. For each of these and other psychiatric conditions, the extent and quality of social support is a strong determinant of outcome such that high social support predicts symptom improvement and remission. Despite the central role of interpersonal factors in psychiatric illness, the neurobiology of social impairments remains largely unexplored, in part due to difficulties eliciting and quantifying interpersonal processes in a parametric manner. Recent advances in functional neuroimaging, combined with multiplayer exchange games drawn from behavioral economics, and computational/quantitative approaches more generally, provide a fitting paradigm within which to study interpersonal function and dysfunction in psychiatric conditions. In this review, we outline the importance of interpersonal factors in psychiatric illness and discuss ways in which neuroeconomics provides a tractable framework within which to examine the neurobiology of social dysfunction.

Damage To Dorsolateral Prefrontal Cortex Affects Tradeoffs Between Honesty And Self-Interest

Substantial correlational evidence suggests that prefrontal regions are critical to honest and dishonest behavior, but causal evidence specifying the nature of this involvement remains absent. We found that lesions of the human dorsolateral prefrontal cortex (DLPFC) decreased the effect of honesty concerns on behavior in economic games that pit honesty motives against self-interest, but did not affect decisions when honesty concerns were absent. These results point to a causal role for DLPFC in honest behavior.

Complexity of oxytocin's effects in a chronic cocaine dependent population

Behavioral and neuroplastic changes occurring in the development of addiction parallel those that occur in social bonding. This has led to speculation that drugs of abuse co-opt systems that subserve social attachment to shift attachment to drugs of abuse. Oxytocin, a neuropeptide that is important in social bonding, has been shown in rodents to decrease psychostimulant self-administration, locomotor activity, and conditioned place preference, it is unclear what role it may play in human drug addiction. In this double-blind, placebo-controlled crossover study, 23 cocaine-dependent inpatients in court-ordered treatment completed 4 task sessions measuring desire to use cocaine, cue-induced craving, monetary reward decisions and social cognition. Before each session, subjects administered 24 IU of intranasal oxytocin or placebo. Oxytocin increased desire to use cocaine and cue-induced excitability with no effect on cue-induced desire to use. Oxytocin also removed the effect of state anger on several measures of cue reactivity. Response to monetary reward increased under oxytocin and measures of social cognition worsened. The significant increase in the desire for drug and monetary reward as well as the significant decrease in measures of social cognition was small but warrant further study of the effect of oxytocin׳s effect in cocaine dependent subjects. The effect of oxytocin to modulate the relationship between state anger and cue reactivity should be explored further for potential therapeutic use of oxytocin in cocaine dependent patients. These findings are discussed in light of the human and rodent oxytocin literature.

Risky decision making in a laboratory driving task is associated with health risk behaviors during late adolescence but not adulthood

Adolescence is characterized by increasing incidence of health risk behaviors, including experimentation with drugs and alcohol. To fill the gap in our understanding of the associations between risky decision-making and health risk behaviors, we investigated associations between laboratory-based risky decision-making using the Stoplight task and self-reported health risk behaviors. Given that there has been no examination of potential age differences in the associations between risky decision-making and health risk behaviors, we also examined whether the association of risky decision-making with health risk behaviors is consistent across adolescence and adulthood using two-group structural equation modeling (SEM). The results indicated significant differences across the two age groups: adolescents (17–20 year olds) who took more risks on the Stoplight task reported greater frequency and earlier onset of substance use, whereas stoplight performance was not associated with substance use frequency or onset among adults (31–61 year olds). Our findings suggest that a laboratory-based measure of risky decision-making is significantly related to health risk behaviors among adolescents but not among adults.

Neural computations underlying social risk sensitivity.

Under standard models of expected utility, preferences over stochastic events are assumed to be independent of the source of uncertainty. Thus, in decision-making, an agent should exhibit consistent preferences, regardless of whether the uncertainty derives from the unpredictability of a random process or the unpredictability of a social partner. However, when a social partner is the source of uncertainty, social preferences can influence decisions over and above pure risk attitudes (RA). Here, we compared risk-related hemodynamic activity and individual preferences for two sets of options that differ only in the social or non-social nature of the risk. Risk preferences in social and non-social contexts were systematically related to neural activity during decision and outcome phases of each choice. Individuals who were more risk averse in the social context exhibited decreased risk-related activity in the amygdala during non-social decisions, while individuals who were more risk averse in the non-social context exhibited the opposite pattern. Differential risk preferences were similarly associated with hemodynamic activity in ventral striatum at the outcome of these decisions. These findings suggest that social preferences, including aversion to betrayal or exploitation by social partners, may be associated with variability in the response of these subcortical regions to social risk.

Alterations in affective processing of attack images following September 11, 2001†‡

The events of September 11, 2001 created unprecedented uncertainty about safety in the United States and created an aftermath with significant psychological impact across the world. This study examined emotional information encoding in 31 healthy individuals whose stress response symptoms ranged from none to a moderate level shortly after the attacks as assessed by the Impact of Event Scale-Revised. Participants viewed attack-related, negative (but attack-irrelevant), and neutral images while their event-related brain potentials (ERPs) were recorded. Attack images elicited enhanced P300 relative to negative and neutral images, and emotional images prompted larger slow waves than neutral images did. Total symptoms were correlated with altered N2, P300, and slow wave responses during valence processing. Specifically, hyperarousal and intrusion symptoms were associated with diminished stimulus discrimination between neutral and unpleasant images; avoidance symptoms were associated with hypervigilance, as suggested by reduced P300 difference between attack and other images and reduced appraisal of attack images as indicated by attenuated slow wave. The findings in this minimally symptomatic sample are compatible with the alterations in cognition in the posttraumatic stress disorder (PTSD) literature and are consistent with a dimensional model of PTSD.