Neural Representations of Death in the Cortical Midline Structures Promote Temporal Discounting.

Death is an important reminder that our lives are finite. Although some studies have shown that thinking about one's own death increases temporal discounting (i.e., the devaluing of future rewards), the underlying neural mechanisms are still unknown. In a functional magnetic resonance imaging experiment, we compared the neural and behavioral processes of temporal discounting across four conditions involving distinct types of future thinking (death related, negative, neutral, and positive). Replicating prior research, the behavioral evidence showed that temporal discounting increased when thinking about one's own future death. Multivoxel pattern analysis showed that death-related future thinking was decoded in default mode regions, including the inferior parietal lobule, precuneus, and medial prefrontal cortex (MPFC). When future thinking was death related (vs. negative), increased temporal discounting was associated with a higher decoding accuracy in the precuneus and MPFC. The present findings suggest that death-related neural representations are distributed across default mode regions, and neural populations in the cortical midline structures play a crucial role in the integration of one's own death into economic decision-making.

Executive control and faithfulness: only long-term romantic relationships require prefrontal control.

Individuals in the early stages of a romantic relationship generally express intense passionate love toward their partners. This observation allows us to hypothesize that the regulation of interest in extra-pair relationships by executive control, which is supported by the function of the prefrontal cortex, is less required in individuals in the early stages of a relationship than it is in those who are in a long-term relationship. To test this hypothesis, we asked male participants in romantic relationships to perform a go/no-go task during functional magnetic resonance imaging (fMRI), which is a well-validated task that can measure right ventrolateral prefrontal cortex (VLPFC) activity implicated in executive control. Subsequently, the participants engaged in a date-rating task in which they rated how much they wanted to date unfamiliar females. We found that individuals with higher right VLPFC activity better regulated their interest in dates with unfamiliar females. Importantly, this relationship was found only in individuals with long-term partners, but not in those with short-term partners, indicating that the active regulation of interest in extra-pair relationships is required only in individuals in a long-term relationship. Our findings extend previous findings on executive control in the maintenance of monogamous relationships by highlighting the role of the VLPFC, which varies according to the stage of the romantic relationship.

Implicit attitudes and executive control interact to regulate interest in extra-pair relationships.

Do we actively maintain monogamous relationships by force of will, or does monogamy flow automatically? During functional magnetic resonance imaging (fMRI), male participants in a romantic relationship performed the Implicit Association Test (IAT) to evaluate implicit attitudes toward adultery and a go/no-go task to measure prefrontal activity implicated in explicit executive control. Subsequently, they were engaged in a date-rating task in which they rated how much they wanted to date unfamiliar females. We found that the individuals with higher prefrontal activity during go/no-go task could regulate the interest for dates with unattractive females; moreover, the individuals with both a stronger negative attitude toward adultery and higher prefrontal activity could regulate their interest for dates with attractive females, and such individuals tended to maintain longer romantic relationships with a particular partner. These results indicate that regulation of amorous temptation via monogamous relationship is affected by the combination of automatic and reflective processes.

Reduced orbitofrontal cortical volume is associated with interdependent self-construal.

Interdependent self-construal refers to a view of the self as embedded in relationships with others. Prior work suggests that this construal is linked to a strong value placed on social obligations and duties. Interdependent people are therefore cognitively attuned to others and various social events in their surroundings while down-regulating their personal goals. In the present work, we examined whether structural properties of the brain predict interdependent self-construal. We performed a structural magnetic resonance imaging on 135 Japanese young adults while assessing (i) independent and interdependent self-construals and (ii) the degree to which individuals form vivid images of external objects (object imagery). The cortical volume of the orbitofrontal cortex (OFC) (a core cortical region responsible for value-based decisionmaking and, thus, inherently involved in personal goals and desires) inversely predicted interdependent self-construal. Further analysis found that the highest level of interdependent self-construal is achieved when those who are relatively low in the OFC volume are simultaneously high in object imagery, consistent with previous evidence that interdependence, as realized via obligation and duty, requires both the reduced self-interest and vigilant cognitive attunement to environmental context.

Tolerating dissimilar other when primed with death: neural evidence of self-control engaged by interdependent people in Japan.

Mortality salience (MS) has been shown to lead to derogation of others with dissimilar worldviews, yet recent research has shown that Asian-Americans who presumably adopt an interdependent self-construal (SC) tend to reveal greater tolerance after MS induction. In the present study, we demonstrated that Japanese individuals who are high on interdependent SC indeed show greater tolerance toward worldview-threatening other in the MS (vs control) condition, thus replicating the prior research. Extending this research, we also found that interdependent people's tolerance toward worldview-threatening other was mediated by increased activity in the right ventrolateral prefrontal cortex in the MS condition. These data suggested that when exposed to death-related stimuli, highly interdependent individuals may spontaneously activate their neural self-control system which may serve to increase tolerance toward others.

The neural basis of individual differences in mate poaching.

This study tested the hypothesis that individual differences in the activity of the orbitofrontal cortex, a region implicated in value-based decision-making, are associated with the preference for a person with a partner, which could lead to mate poaching. During functional magnetic resonance imaging (fMRI), male participants were presented with facial photographs of (a) attractive females with a partner, (b) attractive females without a partner, (c) unattractive females with a partner, and (d) unattractive females without a partner. The participants were asked to rate the degree to which they desired a romantic relationship with each female using an 8-point scale. The participants rated attractive females higher than unattractive females, and this effect was associated with ventral striatum activation. The participants also indicated lower ratings for females with a partner than for females without a partner, and this effect was associated with parietal cortex activation. As predicted, the participants characterized by higher orbitofrontal activity demonstrated a greater willingness to engage in a romantic relationship with females who have a partner compared with females who do not have a partner. These results are the first to provide a possible neural explanation for why certain individuals are willing to engage in mate poaching.

Self-esteem modulates amygdala-ventrolateral prefrontal cortex connectivity in response to mortality threats.

Reminders of death often elicit defensive responses in individuals, especially among those with low self-esteem. Although empirical evidence indicates that self-esteem serves as a buffer against mortality threats, the precise neural mechanism underlying this effect remains unknown. We used functional magnetic resonance imaging (fMRI) to test the hypothesis that self-esteem modulates neural responses to death-related stimuli, especially functional connectivity within the limbic-frontal circuitry, thereby affecting subsequent defensive reactions. As predicted, individuals with high self-esteem subjected to a mortality threat exhibited increased amygdala-ventrolateral prefrontal cortex (VLPFC) connectivity during the processing of death-related stimuli compared with individuals who have low self-esteem. Further analysis revealed that stronger functional connectivity between the amygdala and the VLPFC predicted a subsequent decline in responding defensively to those who threaten one's beliefs. These results suggest that the amygdala-VLPFC interaction, which is modulated by self-esteem, can reduce the defensiveness caused by death-related stimuli, thereby providing a neural explanation for why individuals with high self-esteem exhibit less defensive reactions to mortality threats.

Non-conscious neural regulation against mortality concerns.

Social psychological studies have shown that an experience of threat such as an encounter with death-related stimuli and social exclusion results in tuning toward positive emotional information. Neuroimaging studies have also begun to uncover the neural basis of threat coping, and in this literature, the activity of the right ventrolateral prefrontal cortex (rVLPFC) has been suggested to play a key role in detection and regulation of threats. Using near-infrared spectroscopy (NIRS), we examined the activity of rVLPFC while participants were subliminally primed with the concept of "death" or the control concept "pain". We found greater rVLPFC activities relative to the prior baseline in the death prime condition, and furthermore, these activities negatively correlated with the evaluation of the positive (but not negative) essay. These data provide initial evidence to suggest that lesser neuronal regulation of threat, when it is first encountered, may lead to subsequent regulation by affect tuning.

Family socioeconomic status modulates the coping-related neural response of offspring.

Substantial research links economic adversity to poor coping in stressful or threatening environments. Neuroimaging studies suggest that activation of the right ventrolateral prefrontal cortex (rVLPFC) plays a key role in self-control, and it seems that individual differences in neurocognitive systems underlying self-control are determined in part by subjective childhood socioeconomic status (SES). The present study used near-infrared spectroscopy (NIRS) to investigate whether subjective childhood SES moderates rVLPFC activity during one form of threatening environment: social exclusion. Twenty-five undergraduates participated in a NIRS session in which they were socially included and then excluded during an online ball-tossing game. Lower subjective childhood SES was associated with higher levels of social distress and lower levels of rVLPFC activity during social exclusion. The present findings suggest that early family environments are reliably associated with deficits in offspring coping resources and processes, as well as with difficulties in regulating interpersonal circumstances.

Temporal distance insulates against immediate social pain: an NIRS study of social exclusion.

Social exclusion often evokes social pain in excluded individuals. Although this pain can trigger various interpersonal difficulties (e.g., aggression, depression), it is still unclear which psychological approach might best help to regulate social pain. However, recent work suggests that temporal distance helps to facilitate adaptive coping and self-control. The present study measured ventrolateral prefrontal cortex (VLPFC) activity during social exclusion, using near-infrared spectroscopy (NIRS) to examine the functional relationship between "temporal distance approach," or thinking about the distant future, and the social pain regulation process. Participants that imagined the distant future, next year, and beyond, felt less social pain and showed increased right (r)VLPFC activity during social exclusion, as compared to imagining events in the near future, such as tonight and tomorrow. Furthermore, rVLPFC activity mediated the relationship between temporal distance and social pain. On the basis of these findings, the effect of temporal distance on the process of adaptation after social exclusion is discussed. It is suggested that temporal distance moderates the process of regulating the impact of social exclusion.

Does higher general trust serve as a psychosocial buffer against social pain? An NIRS study of social exclusion.

Social exclusion evokes social pain in excluded individuals. Neuroimaging studies suggest that this social pain is associated with activation of the dorsal anterior cingulate cortex (dACC), with further regulation of social pain being reflected in activation of the right ventrolateral prefrontal cortex (rVLPFC). The present study focused on factors that influence activation of the rVLPFC during social exclusion. We conducted a near-infrared spectroscopy (NIRS) experiment to investigate whether two psychosocial resources (general trust and trait self-esteem) increase rVLPFC activity during social exclusion, thereby buffering against social pain. Thirty-seven undergraduates participated in an NIRS session in which they were socially rejected during an online ball-tossing game. Levels of general trust and trait self-esteem were negatively correlated with self-reported social pain in the exclusion conditions. Furthermore, general trust was positively correlated with rVLPFC activity, although there was no such relationship with self-esteem. rVLPFC activity mediated the relationship between general trust levels and social pain. The rVLPFC appears to be critical for the regulation of social pain. Taken together, these findings suggest that general trust and trait self-esteem probably have different impacts at different times over the course of a series of adaptive processes, all geared toward the modulation of social pain.