Peers influence adolescent reward processing,but not response inhibition

Most adolescent risk taking occurs in the presence of peers. Prior research suggests that peers alter adolescents’ decision making by increasing reward sensitivity and the engagement of regions involved in the processing of rewards, primarily the striatum. However, the potential influence of peers on the capacity for impulse control, and the associated recruitment of the brain’s control circuitry, has not yet been adequately examined. In the current study, adolescents underwent functional neuroimaging while they completed interleaved rounds of risk-taking and response-inhibition tasks. Social context was manipulated such that the participants believed they were either playing alone and unobserved, or watched by an anonymous peer. Compared to those who completed the tasks alone, adolescents in the peer condition took more risks during the risk-taking task and exhibited relatively heightened activation of the striatum. Activity within this striatal region also predicted individual differences in overall risk taking. In contrast, the presence of peers had no effect on behavioral response inhibition and had minimal impact on the engagement of typical cognitive control regions. In a subregion of the anterior insula engaged mutually by both tasks, activity was again found to be sensitive to social context during the risk-taking task, but not during the response-inhibition task. These findings extend the evidence that the presence of peers biases adolescents towards risk taking by increasing reward sensitivity rather than disrupting cognitive control.     

共情对亲社会行为的影响及神经基础

亲社会行为是指那些使他人获益的行为,这类行为具有重要的进化意义和现实意义。作为影响亲社会行为的重要因素,共情在认知神经科学领域得到了广泛研究。脑岛等脑区的激活与消极情绪体验有关,是情绪共情的神经基础,利于产生亲社会行为动机;颞顶联合区等脑区参与对他人意图的理解,是认知共情的神经基础,利于个体选择有效方式帮助别人。女性在共情时激活额下回等与情绪有关的脑区,而男性在共情时激活颞顶联合区等与认知有关的脑区,这为男女个体在亲社会行为表现上的差异提供了新证据。未来研究应完善与亲社会行为有关的脑区功能的解释,综合多种影响因素,结合病理学研究考察共情对亲社会行为的影响及神经基础。     

基于预期理论的风险决策的神经机制

预期理论基于对期望效用理论的批判与发展,提出了价值函数与权重函数,对以往风险决策研究中所发现的现象进行了很好的预测与解释。预期理论的核心概念包括参照依赖、损失规避与权重函数。基于预期理论的一些决策偏差包括框架效应、禀赋效应和默认偏差也部分揭示了与人们风险决策有关的脑区。近年来,通过采用功能性核磁共振等脑成像手段对预期理论的一些核心成分进行的研究表明,涉及到人们风险决策的脑区主要有前额叶、纹状体、脑岛与杏仁核。未来的研究可以从预期理论的产生根源、个体发展以及遗传基因等角度进行进一步的探讨。     

Us versus them: social identity shapes neural responses to intergroup competition and harm

Intergroup competition makes social identity salient, which in turn affects how people respond to competitors' hardships. The failures of an in-group member are painful, whereas those of a rival out-group member may give pleasure-a feeling that may motivate harming rivals. The present study examined whether valuation-related neural responses to rival groups' failures correlate with likelihood of harming individuals associated with those rivals. Avid fans of the Red Sox and Yankees teams viewed baseball plays while undergoing functional magnetic resonance imaging. Subjectively negative outcomes (failure of the favored team or success of the rival team) activated anterior cingulate cortex and insula, whereas positive outcomes (success of the favored team or failure of the rival team, even against a third team) activated ventral striatum. The ventral striatum effect, associated with subjective pleasure, also correlated with self-reported likelihood of aggressing against a fan of the rival team (controlling for general aggression). Outcomes of social group competition can directly affect primary reward-processing neural systems, which has implications for intergroup harm.     

The triadic systems model perspective and adolescent risk taking

In this special issue, Ernst (2014) outlines the triadic systems model, which focuses on the balanced interaction among three functional neural systems: the prefrontal cortex (regulation/control), striatum (motivation/approach), and amygdala (emotion/avoidance). Asynchrony in maturation timelines, coupled with less mature connectivity across brain regions, is thought to result in unique vulnerabilities for risk taking during the adolescent age period. Yet, the research evidence linking the triadic systems model to differences in risk taking across adolescence and adulthood is equivocal, and few studies have examined how neural development is associated with real-world behavior. In this commentary, we outline research on adolescent risk taking which highlights the importance of considering trait level and situational conditions when examining associations between neural systems and behavior, as well as the need to adopt a lifespan perspective.     

Individual differences in the anterior insula are associated with the likelihood of financially helping versus harming others

The neural basis of individual differences in positive and negative social decisions and behaviors in healthy populations is yet undetermined. Recent work has focused on the potential role of the anterior insula in guiding social and nonsocial decision making, but the specific nature of its activation during such decision making remains unclear. To identify the neural regions mediating individual differences in helpful and harmful decisions and to assess the nature of insula activation during such decisions, in the present study we used a novel fMRI task featuring intentional and unintentional decisions to financially harm or help persons in need. Based on a whole-brain, unbiased approach, our findings indicate that individual differences in dorsal anterior insula, anterior cingulate cortex (ACC), and right temporo-parietal junction activation are associated with behavioral tendencies to financially harm or help another. Furthermore, activity in the dorsal anterior insula and ACC was greatest during unintended outcomes, whether these were gains or losses for a charity or for oneself, supporting models of the role of these regions in salience prediction error signaling. Together, the results suggest that individual differences in risk anticipation, as reflected in the dorsal anterior insula and dorsal ACC, guide social decisions to refrain from harming others.     

赌博障碍的认知功能缺陷及神经基础

赌博障碍是指持续且反复的赌博行为,给个人、家庭和社会都带来了严重后果,近年来受到越来越多研究者的关注。本研究总结了赌博障碍的认知功能缺陷及其神经基础,主要集中在如下四个方面：①认知扭曲、②奖赏和惩罚敏感性、③注意偏向和④决策。未来研究应多从认知神经科学角度深入探究赌博障碍的发生机制和发展过程,关注大脑结构变化及功能网络改变,并将其整合到一个统一的神经生物机制框架中,找到更加有效的干预和治疗手段。     

Brain activity for visual judgment of lifted weight

It is well established that humans can recognize high-level aspects from point-light biological motion, such as gender and mood. If the task is to judge the manipulated weight we expected that sensorimotor regions should be recruited in the brain. Moreover, we have recently shown that chronic pain in a limb that is involved in the presented movement disturbs the weight judgment. We therefore hypothesized that some cortical regions usually activated during the processing of pain will also be activated while viewing point-light biological motion with the instruction to judge the manipulated weights. We investigated point-light biological motion of two types of movements performed with different weights in a blocked fMRI experiment in healthy subjects. In line with our a priori hypothesis, we found strong activity in the regions known as the neuromatrix of pain, such as the anterior cingulate (ACC), insula, as well as primary and secondary somatosensory regions. We also found activation in the occipital and temporal regions that are typical for biological motion, as well as regions in the cerebellum and prefrontal cortex. The activation of the somatosensory regions probably serves the judgment of the biological motion stimuli. Activation of the anterior cingulate and the insula might be explained by their role in the integration of behaviorally relevant information. Alternatively, these structures are known to be involved in the processing of nociceptive information and pain. So it seems possible that the interference between judgment of weights and perception of pain in chronic pain patients occurs in the somatosensory areas, anterior cingulate and/or insula. This finding provides important information as to the underlying mechanisms used for the weight judgment task, but also why chronic pain interferes with this task.     

赌博障碍的认知功能缺陷及神经基础

赌博障碍是指持续且反复的赌博行为,给个人、家庭和社会都带来了严重后果,近年来受到越来越多研究者的关注。本研究总结了赌博障碍的认知功能缺陷及其神经基础,主要集中在如下四个方面：①认知扭曲、②奖赏和惩罚敏感性、③注意偏向和④决策。未来研究应多从认知神经科学角度深入探究赌博障碍的发生机制和发展过程,关注大脑结构变化及功能网络改变,并将其整合到一个统一的神经生物机制框架中,找到更加有效的干预和治疗手段。     

Anterior insula activity predicts the influence of positively framed messages on decision making

The neural mechanisms underlying the influence of persuasive messages on decision making are largely unknown. We address this issue using event-related fMRI to investigate how informative messages alter risk appraisal during choice. Participants performed the Iowa Gambling Task while viewing a positively framed, negatively framed, or control message about the options. The right anterior insula correlated with improvement in choice behavior due to the positively framed but not the negatively framed message. With the positively framed message, there was increased activation proportional to message effectiveness when less-preferred options were chosen, consistent with a role in the prediction of adverse outcomes. In addition, the dorsomedial and the left dorsolateral prefrontal cortex correlated with overall decision quality, regardless of message type. The dorsomedial region mediated the relationship between the right anterior insula and decision quality with the positively framed messages. These findings suggest a network of frontal brain regions that integrate informative messages into the evaluation of options during decision making. Supplemental procedures and results for this article may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.     

Neural Correlates of Emotional Reactivity in Sensation Seeking

ABSTRACT— High sensation seeking has been linked to increased risk for drug abuse and other negative behavioral outcomes. This study explored the neurobiological basis of this personality trait using functional magnetic resonance imaging (fMRI). High sensation seekers (HSSs) and low sensation seekers (LSSs) viewed high- and low-arousal pictures. Comparison of the groups revealed that HSSs showed stronger fMRI responses to high-arousal stimuli in brain regions associated with arousal and reinforcement (right insula, posterior medial orbitofrontal cortex), whereas LSSs showed greater activation and earlier onset of fMRI responses to high-arousal stimuli in regions involved in emotional regulation (anterior medial orbitofrontal cortex, anterior cingulate). Furthermore, fMRI response in anterior medial orbitofrontal cortex and anterior cingulate was negatively correlated with urgency. Finally, LSSs showed greater sensitivity to the valence of the stimuli than did HSSs. These distinct neurobiological profiles suggest that HSSs exhibit neural responses consistent with an overactive approach system, whereas LSSs exhibit responses consistent with a stronger inhibitory system.     

Gender Differences in the Effects of Community Violence on Mental Health Outcomes in a Sample of Low-Income Youth Receiving Psychiatric Care

Previous research suggests that community violence impacts mental health outcomes, but much of this research has not (a) distinguished between different types of community violence, (b) examined gender differences, and (c) focused on youth living in urban poverty. The current study addresses these questions. Participants were 306 youth (23 % girls) and one parent/guardian receiving outpatient psychiatric services for disruptive behavior disorders in a large urban city. Youth and parents reported on youth’s experience of different types of community violence (being a direct victim, hearing reports, and witnessing violence), and whether violence was directed toward a stranger or familiar. Outcomes included youth externalizing, internalizing, and posttraumatic stress symptoms assessed via parent and youth reports. Being a direct victim of violence accords risk for all mental health outcomes similarly for both boys and girls. However, gender differences emerged with respect to indirect violence, such that girls who hear reports of violence against people they know are at increased risk for all assessed mental health outcomes, and girls who witness violence against familiars are at increased risk for externalizing mental health symptoms in particular. There are gender differences in violence-related mental health etiology, with implications for intervention assessment and design.     

压力下一搏：压力如何影响个体风险寻求

压力促使个体风险寻求已得到许多研究的验证和支持, 但对于该现象背后的根本机制缺乏深入探讨和整合。模型指出, 压力诱发认知资源损耗和心理需要失衡, 导致个体执行控制功能减弱, 奖赏寻求增加, 这两者引起对风险选项价值的高估、风险感知的降低和启发式决策策略的使用, 最终导致风险寻求。期望效用论、预期理论、双系统理论和风险敏感理论的视角能各有侧重地解析模型中的路径。最后, 基于模型梳理了边界条件, 并提出未来可关注压力下执行功能、认知和情绪的交互以及慢性压力的影响和调控。     

睡眠质量对冒险行为影响的证据及解析

睡眠质量影响个体冒险行为已得到许多研究的验证和支持。睡眠缺失既影响大脑前额叶功能的完整性, 也影响杏仁核、纹状体等脑区的激活, 从而降低了个体对危险的知觉和对损失的敏感, 导致冒险意愿和冒险行为增加。已往相关研究多以成人群体为研究对象, 且忽略了个体特质与所处社会环境在睡眠质量与冒险行为关系中的交互影响。由于青少年期睡眠不足和高冒险行为普遍存在, 未来研究应对青少年睡眠质量与冒险行为的关系及其中的影响作用机制, 尤其是神经机制给予更多关注。     

Behavioral, but not reward, risk modulates activation of prefrontal, parietal, and insular cortices

Risky decisions may involve uncertainty about possible outcomes (i.e., reward risk) or uncertainty about which action should be taken (i.e., behavioral risk). Determining whether different forms of risk have distinct neural correlates is a central goal of neuroeconomic research. In two functional magnetic resonance imaging experiments, subjects viewed shapes that had well-learned response-reward contingencies. Magnitude of a monetary reward was held constant within one experiment, whereas expected value was held constant within the other. Response selection, in the absence of behavioral risk, evoked activation within a broad set of brain regions, as had been found in prior studies. However, behavioral risk additionally modulated activation in prefrontal, parietal, and insular regions, within which no effect of reward risk was observed. Reward delivery, in comparison with omission, evoked increased activity in the ventromedial prefrontal cortex and the nucleus accumbens. We conclude that distinct brain systems are recruited for the resolution of different forms of risk.     

Gender Differences in Depression

From early adolescence through adulthood, women are twice as likely as men to experience depression. Many different explanations for this gender difference in depression have been offered, but none seems to fully explain it. Recent research has focused on gender differences in stress responses, and in exposure to certain stressors. I review this research and describe how gender differences in stress experiences and stress reactivity may interact to create women's greater vulnerability to depression.     

Variables influencing the neural correlates of perceived risk of physical harm

Many human activities involve a risk of physical harm. However, not much is known about the specific brain regions involved in decision making regarding these risks. To explore the neural correlates of risk perception for physical harms, 19 participants took part in an event-related fMRI study while rating risky activities. The scenarios varied in level of potential harm (e.g., paralysis vs. stubbed toe), likelihood of injury (e.g., 1 chance in 100 vs. 1 chance in 1,000), and format (frequency vs. probability). Networks of brain regions were responsive to different aspects of risk information. Cortical language- processing areas, the middle temporal gyrus, and a region around the bed nucleus of stria terminalis responded more strongly to high- harm conditions. Prefrontal areas, along with subcortical ventral striatum, responded preferentially to high- likelihood conditions. Participants rated identical risks to be greater when information was presented in frequency format rather than probability format. These findings indicate that risk assessments for physical harm engage a broad network of brain regions that are sensitive to the severity of harm, the likelihood of risk, and the framing of risk information.     

The multiple neural networks of familiarity: A meta-analysis of functional imaging studies

Recent research has demonstrated the critical role of the feeling of familiarity in recognition memory. Various neuroimaging paradigms have been developed to identify the brain regions that sustain the processing of familiarity; however, there is still considerable controversy about the functional significance of each brain region implicated in familiarity-based retrieval. Here, we focused on the differences between paradigms that assess familiarity, with or without the encoding phase. We used the activation likelihood estimation (ALE) algorithm to conduct a whole-brain meta-analysis of neuroimaging studies that involved a familiarity task. Sixty-nine studies, performed in healthy subjects to determine the specific functions of the identified regions in familiarity processing, were finally selected. Distinct subanalyses were performed according to the experimental procedures used in the original studies. The ALE clusters that were highlighted revealed common activations for paradigms with and without encoding in the prefrontal cortex and in the parietal cortex. Additionally, supplementary activations related to specific familiarity (i.e., without the encoding phase) were observed in the limbic system (i.e., the amygdala, hippocampus, cingulate cortex, and insula) and in the associative sensory areas. The differences in the reported findings for different procedures are possibly due to differences in the concept of familiarity. To aid the exploration of the neural correlates of familiarity in future studies, the strengths and weaknesses of these experimental procedures are critically discussed.