Epstein-Barr virus-positive monoclonal lymphoplasmacytic proliferation associated with neurosyphilis in an immunocompetent patient: A case report.

Syphilis is an infectious disease caused by the spirochete bacterium Treponema pallidum. Neurosyphilis results from the infection of the nervous system with Treponema pallidum, which can occur at any stage of syphilis. Neurosyphilis is often overlooked because of its rarity. Early-stage neurosyphilis with brain mass formation is rare. We present a case of early-stage neurosyphilis with prominent Epstein-Barr virus (EBV)-positive monoclonal lymphoplasmacytic proliferation in an immunocompetent patient. A 36-year-old man presented with a chief complaint of a progressively worsening headache, a newly developed skin rash, and a fever. Magnetic resonance imaging showed a mass lesion, which measured 18 mm in diameter, in the left frontal lobe of the cerebrum. The patient underwent an emergency operation to remove the abscess. A pathological investigation revealed complex findings. There was an abscess in the cerebrum. Lymphoplasmacytic meningitis was also noted. In addition, a vaguely nodular lesion, which was composed of plasmacytoid and lymphoid cells, was observed around the abscess. Immunohistochemically, an anti-Treponema pallidum antibody revealed numerous Treponemas around the abscess. In situ hybridization revealed that the plasmacytoid and lymphoid cells were Epstein-Barr encoding region (EBER)-positive; κ-positive cells were significantly more prevalent than λ-positive cells, suggesting light-chain restriction. Postoperatively, parenteral antibiotics were administered for four weeks. The patient has been free of recurrence for two years since the surgery. No association between neurosyphilis and EBV-positive lymphoplasmacytic proliferation has ever been reported. Mass formation in early-stage neurosyphilis is an exceptionally rare event. The present case indicates that in syphilis patients, lymphoproliferative disorders that lead to mass formation may be caused by concomitant EBV reactivation. Furthermore, when treating patients with mass lesions of the central nervous system, it is important to check their medical history and perform laboratory screening for infectious diseases to avoid overlooking syphilis infections.

Response time in economic games reflects different types of decision conflict for prosocial and proself individuals.

Behavioral and neuroscientific studies explore two pathways through which internalized social norms promote prosocial behavior. One pathway involves internal control of impulsive selfishness, and the other involves emotion-based prosocial preferences that are translated into behavior when they evade cognitive control for pursuing self-interest. We measured 443 participants' overall prosocial behavior in four economic games. Participants' predispositions [social value orientation (SVO)] were more strongly reflected in their overall game behavior when they made decisions quickly than when they spent a longer time. Prosocially (or selfishly) predisposed participants behaved less prosocially (or less selfishly) when they spent more time in decision making, such that their SVO prosociality yielded limited effects in actual behavior in their slow decisions. The increase (or decrease) in slower decision makers was prominent among consistent prosocials (or proselfs) whose strong preference for prosocial (or proself) goals would make it less likely to experience conflict between prosocial and proself goals. The strong effect of RT on behavior in consistent prosocials (or proselfs) suggests that conflict between prosocial and selfish goals alone is not responsible for slow decisions. Specifically, we found that contemplation of the risk of being exploited by others (social risk aversion) was partly responsible for making consistent prosocials (but not consistent proselfs) spend longer time in decision making and behave less prosocially. Conflict between means rather than between goals (immediate versus strategic pursuit of self-interest) was suggested to be responsible for the time-related increase in consistent proselfs' prosocial behavior. The findings of this study are generally in favor of the intuitive cooperation model of prosocial behavior.

Cortical thickness of the dorsolateral prefrontal cortex predicts strategic choices in economic games.

Human prosociality has been traditionally explained in the social sciences in terms of internalized social norms. Recent neuroscientific studies extended this traditional view of human prosociality by providing evidence that prosocial choices in economic games require cognitive control of the impulsive pursuit of self-interest. However, this view is challenged by an intuitive prosociality view emphasizing the spontaneous and heuristic basis of prosocial choices in economic games. We assessed the brain structure of 411 players of an ultimatum game (UG) and a dictator game (DG) and measured the strategic reasoning ability of 386. According to the reflective norm-enforcement view of prosociality, only those capable of strategically controlling their selfish impulses give a fair share in the UG, but cognitive control capability should not affect behavior in the DG. Conversely, we support the intuitive prosociality view by showing for the first time, to our knowledge, that strategic reasoning and cortical thickness of the dorsolateral prefrontal cortex were not related to giving in the UG but were negatively related to giving in the DG. This implies that the uncontrolled choice in the DG is prosocial rather than selfish, and those who have a thicker dorsolateral prefrontal cortex and are capable of strategic reasoning (goal-directed use of the theory of mind) control this intuitive drive for prosociality as a means to maximize reward when there are no future implications of choices.

In search of Homo economicus.

Homo economicus, a model for humans in neoclassical economics, is a rational maximizer of self-interest. However, many social scientists regard such a person as a mere imaginary creature. We found that 31 of 446 residents of relatively wealthy Tokyo suburbs met the behavioral definition of Homo economicus. In several rounds of economic games, participants whose behavior was consistent with this model always apportioned the money endowed by the experimenter to themselves, leaving no share for their partners. These participants had high IQs and a deliberative decision style. An additional 39 participants showed a similar disregard for other people's welfare, although they were slightly more altruistic than those in the Homo economicus group. The psychological composition of these quasi-Homo economicus participants was distinct from that of participants in the Homo economicus group. Although participants in the latter group behaved selfishly on the basis of rational calculations, those in the former group made selfish choices impulsively. The implications of these findings concerning the two types of extreme noncooperators are discussed.

[Why do people behave altruistically even when nobody would observe their behavior?].

Why do people behave altruistically toward others, even in situations where nobody would observe their behavior? We formulated the following hypothesis regarding this question: "Reputations are decided by behaviors in situations that nobody can observe, rather than by behaviors in situations that can be observed by others." The validity of this hypothesis was examined through a Prisoner's Dilemma experiment. In the first stage, participants played the Prisoner's Dilemma game in a situation where nobody could observe them. In the second stage, participants selected another partner in the game, based on information about their behavior in the first stage. The results indicated that participants tended to choose people that behaved altruistically in situations where nobody could observe them. Furthermore, this tendency was stronger with cooperative participants. These results support the hypothesis of this study.

Proselfs depend more on model-based than model-free learning in a non-social probabilistic state-transition task.

Humans form complex societies in which we routinely engage in social decision-making regarding the allocation of resources among ourselves and others. One dimension that characterizes social decision-making in particular is whether to prioritize self-interest or respect for others-proself or prosocial. What causes this individual difference in social value orientation? Recent developments in the social dual-process theory argue that social decision-making is characterized by its underlying domain-general learning systems: the model-free and model-based systems. In line with this "learning" approach, we propose and experimentally test the hypothesis that differences in social preferences stem from which learning system is dominant in an individual. Here, we used a non-social state transition task that allowed us to assess the balance between model-free/model-based learning and investigate its relation to the social value orientations. The results showed that proselfs depended more on model-based learning, whereas prosocials depended more on model-free learning. Reward amount and reaction time analyses showed that proselfs learned the task structure earlier in the session than prosocials, reflecting their difference in model-based/model-free learning dependence. These findings support the learning hypothesis on what makes differences in social preferences and have implications for understanding the mechanisms of prosocial behavior.

The neuroanatomy of social trust predicts depression vulnerability.

Trust attitude is a social personality trait linked with the estimation of others' trustworthiness. Trusting others, however, can have substantial negative effects on mental health, such as the development of depression. Despite significant progress in understanding the neurobiology of trust, whether the neuroanatomy of trust is linked with depression vulnerability remains unknown. To investigate a link between the neuroanatomy of trust and depression vulnerability, we assessed trust and depressive symptoms and employed neuroimaging to acquire brain structure data of healthy participants. A high depressive symptom score was used as an indicator of depression vulnerability. The neuroanatomical results observed with the healthy sample were validated in a sample of clinically diagnosed depressive patients. We found significantly higher depressive symptoms among low trusters than among high trusters. Neuroanatomically, low trusters and depressive patients showed similar volume reduction in brain regions implicated in social cognition, including the dorsolateral prefrontal cortex (DLPFC), dorsomedial PFC, posterior cingulate, precuneus, and angular gyrus. Furthermore, the reduced volume of the DLPFC and precuneus mediated the relationship between trust and depressive symptoms. These findings contribute to understanding social- and neural-markers of depression vulnerability and may inform the development of social interventions to prevent pathological depression.

Behavioural Differences and Neural Substrates of Altruistic and Spiteful Punishment.

Altruistic punishment following social norm violations promotes human cooperation. However, experimental evidence indicates that some forms of punishment are spiteful rather than altruistic. Using two types of punishment games and seven non-strategic games, we identified strong behavioural differences between altruistic and spiteful punishers. Altruistic punishers who rejected unfair offers in the ultimatum game and punished norm violators in the third-party punishment game behaved pro-socially in various non-strategic games. Spiteful punishers who rejected unfair offers in the ultimatum game but did not punish norm violators in the third-party punishment game behaved selfishly in non-strategic games. In addition, the left caudate nucleus was larger in spiteful punishers than in altruistic punishers. These findings are in contrast to the previous assumption that altruistic punishers derive pleasure from enforcement of fairness norms, and suggest that spiteful punishers derive pleasure from seeing the target experience negative consequences.

Prosocial Behavior Increases with Age across Five Economic Games.

Ontogenic studies of human prosociality generally agree on that human prosociality increases from early childhood through early adulthood; however, it has not been established if prosociality increases beyond early adulthood. We examined a sample of 408 non-student residents from Tokyo, Japan, who were evenly distributed across age (20-59) and sex. Participants played five economic games each separated by a few months. We demonstrated that prosocial behavior increased with age beyond early adulthood and this effect was shown across all five economic games. A similar, but weaker, age-related trend was found in one of three social value orientation measures of prosocial preferences. We measured participants' belief that manipulating others is a wise strategy for social success, and found that this belief declined with age. Participants' satisfaction with the unilateral exploitation outcome of the prisoner's dilemma games also declined with age. These two factors-satisfaction with the DC outcome in the prisoner's dilemma games and belief in manipulation-mediated the age effect on both attitudinal and behavioral prosociality. Participants' age-related socio-demographic traits such as marriage, having children, and owning a house weakly mediated the age effect on prosociality through their relationships with satisfaction with the DC outcome and belief in manipulation.

Moral Bargain Hunters Purchase Moral Righteousness When it is Cheap: Within-Individual Effect of Stake Size in Economic Games.

Despite the repeatedly raised criticism that findings in economic games are specific to situations involving trivial incentives, most studies that have examined the stake-size effect have failed to find a strong effect. Using three prisoner's dilemma experiments, involving 479 non-student residents of suburban Tokyo and 162 students, we show here that stake size strongly affects a player's cooperation choices in prisoner's dilemma games when stake size is manipulated within each individual such that each player faces different stake sizes. Participants cooperated at a higher rate when stakes were lower than when they were higher, regardless of the absolute stake size. These findings suggest that participants were 'moral bargain hunters' who purchased moral righteousness at a low price when they were provided with a 'price list' of prosocial behaviours. In addition, the moral bargain hunters who cooperated at a lower stake but not at a higher stake did not cooperate in a single-stake one-shot game.

Representation of economic preferences in the structure and function of the amygdala and prefrontal cortex.

Social value orientations (SVOs) are economic preferences for the distribution of resources - prosocial individuals are more cooperative and egalitarian than are proselfs. Despite the social and economic implications of SVOs, no systematic studies have examined their neural correlates. We investigated the amygdala and dorsolateral prefrontal cortex (DLPFC) structures and functions in prosocials and proselfs by functional magnetic resonance imaging and evaluated cooperative behavior in the Prisoner's Dilemma game. We found for the first time that amygdala volume was larger in prosocials and positively correlated with cooperation, while DLPFC volume was larger in proselfs and negatively correlated with cooperation. Proselfs' decisions were marked by strong DLPFC and weak amygdala activity, and prosocials' decisions were marked by strong amygdala activity, with the DLPFC signal increasing only in defection. Our findings suggest that proselfs' decisions are controlled by DLPFC-mediated deliberative processes, while prosocials' decisions are initially guided by automatic amygdala processes.

SCGB3A2 Inhibits Acrolein-Induced Apoptosis through Decreased p53 Phosphorylation.

Chronic obstructive pulmonary disease (COPD), a major global health problem with increasing morbidity and mortality rates, is anticipated to become the third leading cause of death worldwide by 2020. COPD arises from exposure to cigarette smoke. Acrolein, which is contained in cigarette smoke, is the most important risk factor for COPD. It causes lung injury through altering apoptosis and causes inflammation by augmenting p53 phosphorylation and producing reactive oxygen species (ROS). Secretoglobin (SCGB) 3A2, a secretory protein predominantly present in the epithelial cells of the lungs and trachea, is a cytokine-like small molecule having anti-inflammatory, antifibrotic, and growth factor activities. In this study, the effect of SCGB3A2 on acrolein-related apoptosis was investigated using the mouse fibroblast cell line MLg as the first step in determining the possible therapeutic value of SCGB3A2 in COPD. Acrolein increased the production of ROS and phosphorylation of p53 and induced apoptosis in MLg cells. While the extent of ROS production induced by acrolein was not affected by SCGB3A2, p53 phosphorylation was significantly decreased by SCGB3A2. These results demonstrate that SCGB3A2 inhibited acrolein-induced apoptosis through decreased p53 phosphorylation, not altered ROS levels.