主观价值计算与整合的神经机制及其影响因素

决策在人类社会发展的历程中扮演着非常重要的作用,而对其神经机制的探讨才不过几十年的时间。基于价值的决策理论,强调人们首先计算和表征事物的价值,随后比较和决策。在人脑中负责主观价值计算的神经基础有腹内侧前额叶皮层、眶额皮层以及其他脑区,而负责价值整合的脑区有腹内侧前额叶皮层、眶额皮层、背外侧前额叶皮层等。其中时间和风险的价值计算有着相同的神经基础,并且人脑可以将不同属性以及成本进行整合形成主观价值,按照曲线交互作用范式进行。通过自我控制、注意和认知调节等方法,同样可以调制人们的主观价值大小。未来需要继续强调模式分析、个体差异、老龄化和基因对价值计算的影响。     

Mental time travel,somatic markers and “myopia for the future”

Patients with damage to the ventromedial prefrontal cortex (VMPFC) are often described as having impaired ability for planning and decision making despite retaining intact capacities for explicit reasoning. The somatic marker hypothesis is that the VMPFC associates implicitly represented affective information with explicit representations of actions or outcomes. Consequently, when the VMPFC is damaged explicit reasoning is no longer scaffolded by affective information, leading to characteristic deficits. These deficits are exemplified in performance on the Iowa Gambling Task (IGT) in which subjects with VMPFC perform significantly worse than neurotypicals in a task which requires them learn from rewarding and punishing experience to make decisions. The somatic marker theory adopts a canonical theory of emotion, in which emotions function as part of a valencing system, to explain the role of affective processes. The first part of the paper argues against this canonical account. The second part provides a different account of the role of the role of the VMPFC in decision-making which does not depend on the canonical account of emotion. Together the first and second parts of the paper provide the basis for a different interpretation of results on the Iowa Gambling Task (IGT). In fact the IGT may be probing a deficit in what has been called mental time travel: the ability to access and use information from previous experience and imaginatively rehearse future experiences as part of the process of deliberation.     

Age-related differences in medial prefrontal activation in response to emotional images

Research has suggested that aging results in a "positivity effect," with young adults dwelling on negative information, and older adults attending to positive information. In order to understand age-related changes in emotional processing underlying this effect, the present fMRI study compared neural activity in young and older adults as they viewed positive, negative, and neutral images. Results indicated a striking age-related reversal in the valence of information eliciting activity within the ventromedial prefrontal cortex (VMPFC). Negative in comparison with positive images activated the VMPFC more for young adults, whereas positive in comparison with negative images activated the VMPFC more for the older adults. The VMPFC is a region associated with the processing of emotional information, and more specifically, with emotion generation and emotion regulation. Therefore, the present results suggest that age-related changes in these processes implemented by the VMPFC contribute to older adults' "positivity effect."     

Toward a taxonomy of attention shifting: Individual differences in fMRI during multiple shift types

Although task switching is often considered one of the fundamental abilities underlying executive functioning and general intelligence, there is little evidence that switching is a unitary construct and little evidence regarding the relationship between brain activity and switching performance. We examined individual differences in multiple types of attention shifting in order to determine whether behavioral performance and fMRI activity are correlated across different types of shifting. The participants (n=39) switched between objects and attributes both when stimuli were perceptually available (external) and when stimuli were stored in memory (internal). We found that there were more switchrelated activations in many regions associated with executive control—including the dorsolateral and medial prefrontal and parietal cortices—when behavioral switch costs were higher (poor performance). Conversely, activation in the ventromedial prefrontal cortex (VMPFC) and the rostral anterior cingulate was consistently correlated with good performance, suggesting a general role for these areas in efficient attention shifting. We discuss these findings in terms of a model of cognitive-emotional interaction in attention shifting, in which reward-related signals in the VMPFC guide efficient selection of tasks in the lateral prefrontal and parietal cortices.     

Neural correlates of intertemporal choice in aggressive behavior

People often have to make decisions between immediate rewards and more long-term goals. Such intertemporal judgments are often investigated in the context of monetary choice or drug use, yet not in regard to aggressive behavior. We combined a novel intertemporal aggression paradigm with functional neuroimaging to examine the role of temporal delay in aggressive behavior and the neural correlates thereof. Sixty-one participants (aged 18–22 years; 37 females) exhibited substantial variability in the extent to which they selected immediate acts of lesser aggression versus delayed acts of greater aggression against a same-sex opponent. Choosing delayed-yet-more-severe aggression was increased by provocation and associated with greater self-control. Preferences for delayed aggression were associated with greater activity in the ventromedial prefrontal cortex (VMPFC) during such choices, and reduced functional connectivity between the VMPFC and brain regions implicated in motor impulsivity. Preferences for immediate aggression were associated with reduced functional connectivity between the VMPFC and the frontoparietal control network. Dispositionally aggressive participants exhibited reduced VMPFC activity, which partially explained and suppressed their preferences for delayed aggression. Blunted VMPFC activity may thus be a neural mechanism that promotes reactive aggression towards provocateurs among dispositionally aggressive individuals. These findings demonstrate the utility of an intertemporal framework for investigating aggression and provide further evidence for the similar underlying neurobiology between aggression and other rewarding behaviors.     

Neural activation underlying cognitive control in the context of neutral and affectively charged pictures in children

The neural correlates of cognitive control for typically developing 9-year-old children were examined using dense-array ERPs and estimates of cortical activation (LORETA) during a go/no-go task with two conditions: a neutral picture condition and an affectively charged picture condition. Activation was estimated for the entire cortex after which data were exported for four regions of interests (ROIs): ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (DLPFC), and orbitofrontal/ventromedial prefrontal cortex (OFC/VMPFC). Results revealed faster reaction times, greater N2 activation, and greater prefrontal activation for the affectively charged picture condition than the neutral picture condition. The findings are discussed in reference to the impact of affective stimuli on recruitment of specific brain regions involved in cognitive control.     

Relationships between executive function,working memory,and decision-making on the Iowa Gambling Task: Evidence from ventromedial patients,dorsolateral patients,and normal subjects

The results of previous studies are inconsistent in regard to the relationship between the Iowa Gambling Task (IGT), working-memory (WM), and executive tasks, and whether these cognitive processes could be considered as mechanisms underlying a decision-making deficit. Moreover, the relationship between the IGT and executive measures is examined based on a limited number of executive tasks, within different populations showing diffuse damage. In addition, there are fewer studies carried out within control participants, with those studies also being inconclusive. It is also suggested that the association of the IGT performance with executive tasks depends on whether the IGT was running under ambiguity or under risk. In this work, all of these issues are studied. Results showed that both patients with ventromedial (VMPFC, N = 10) and dorsolateral (DLPFC, N = 10) prefrontal cortex lesions are significantly impaired on almost all executive tasks, WM tasks, and the IGT. Furthermore, when the IGT is run under risk, there are significant correlations between executive measures and the IGT for the DLPFC patients and the control participants (N = 34) but not the VMPFC patients. No correlation was found between WM tasks and the IGT for both frontal subgroups and control participants. These findings suggested that the mechanisms underlying the IGT deficit differ according to the lesion locations.     

药物成瘾者决策缺陷的特征、机制及干预

药物成瘾者存在决策缺陷, 并表现出冲动性、风险寻求、奖赏失调、躯体内感信号缺失等特征。神经影像学研究表明药物滥用导致成瘾者背外侧前额皮层、前扣带回、眶额叶皮层、腹内侧前额皮层、杏仁核、脑岛等脑区受损, 这些损伤是引发其决策缺陷的主要原因。认知训练有利于提高个体的决策能力, 如目标管理训练和正念冥想等可以增强个体工作记忆、促进自我觉察和以目标为导向的行为; 而非侵入性脑刺激则可以直接改变与成瘾者决策相关脑区的激活状态, 从而提升与决策相关的认知功能。总体而言, 未来认知训练和非侵入性脑刺激在成瘾干预方面仍有广阔的拓展空间。     

Neural affective decision theory: Choices, brains, and emotions

We present a theory and neurocomputational model of how specific brain operations produce complex decision and preference phenomena, including those explored in prospect theory and decision affect theory. We propose that valuation and decision making are emotional processes, involving interacting brain areas that include two expectation-discrepancy subsystems: a dopamine-encoded system for positive events and a serotonin-encoded system for negative ones. The model provides a rigorous account of loss aversion and the shape of the value function from prospect theory. It also suggests multiple distinct neurological mechanisms by which information framing may affect choices, including ones involving anticipated pleasure. It further offers a neural basis for the interactions among affect, prior expectations and counterfactual comparisons explored in decision affect theory. Along with predicting the effects of particular brain disturbances and damage, the model suggests specific neurological explanations for individual differences observed in choice and valuation behaviors.     

The legal self: executive processes and legal theory

When laws or legal principles mention mental states such as intentions to form a contract, knowledge of risk, or purposely causing a death, what parts of the brain are they speaking about? We argue here that these principles are tacitly directed at our prefrontal executive processes. Our current best theories of consciousness portray it as a workspace in which executive processes operate, but what is important to the law is what is done with the workspace content rather than the content itself. This makes executive processes more important to the law than consciousness, since they are responsible for channelling conscious decision-making into intentions and actions, or inhibiting action. We provide a summary of the current state of our knowledge about executive processes, which consists primarily of information about which portions of the prefrontal lobes perform which executive processes. Then we describe several examples in which legal principles can be understood as tacitly singling out executive processes, including principles regarding defendants' intentions or plans to commit crimes and their awareness that certain facts are the case (for instance, that a gun is loaded), as well as excusatory principles which result in lesser responsibility for those who are juveniles, mentally ill, sleepwalking, hypnotized, or who suffer from psychopathy.     

神经美学视角的审美愉悦加工机制

审美对象特有的刺激属性会唤起观赏者特定的情绪或情感反应。个体在欣赏自然、艺术品和其他人类作品时会产生审美愉悦体验。审美愉悦-兴趣模型(PIA)认为, 审美愉悦体验包含审美过程中自动化加工阶段的审美愉悦和控制加工阶段的审美兴趣。近年来, 神经美学研究表明, 负责愉悦和奖赏的眶额叶皮层在审美过程中广泛激活, 是自动化加工阶段初级审美愉悦奖赏的神经基础, 而审美过程中纹状体亚回路中不同的连接和功能作用与两个阶段中审美愉悦的产生都有关联; 上述结果支持了审美愉悦-兴趣模型。但审美高峰体验时默认模式网络(DMN)相关脑区的激活和负责控制与理性思维的外侧前额叶皮层等脑区的失活, 提示在PIA模型强调的自动化加工阶段审美愉悦和控制加工阶段审美兴趣之上, 还有整合升华阶段的审美沉浸愉悦, PIA模型需得到进一步的扩展。未来研究应进一步检验审美愉悦认知加工模型及神经机制, 探索审美对创造力的影响机制和神经基础, 探讨不同审美经验愉悦机制的异同。     

Emotion and decision-making: affect-driven belief systems in anxiety and depression

Emotion processing and decision-making are integral aspects of daily life. However, our understanding of the interaction between these constructs is limited. In this review, we summarize theoretical approaches that link emotion and decision-making, and focus on research with anxious or depressed individuals to show how emotions can interfere with decision-making. We integrate the emotional framework based on valence and arousal with a Bayesian approach to decision-making in terms of probability and value processing. We discuss how studies of individuals with emotional dysfunctions provide evidence that alterations of decision-making can be viewed in terms of altered probability and value computation. We argue that the probabilistic representation of belief states in the context of partially observable Markov decision processes provides a useful approach to examine alterations in probability and value representation in individuals with anxiety and depression, and outline the broader implications of this approach.     

Using computational neuroscience to investigate the neural correlates of cognitive-affective integration during covert decision making

We presented a proposed neural level mechanism for the integration of cognitive and affective information during covert decision making. The central idea is that the ventromedial prefrontal cortex establishes predicted outcomes of responses through its connections with the amygdala, and that this information is passed through the context-moderated gateway in the nucleus accumbens in order to promote behaviours that are most beneficial to the long term survival of the organism. We then implemented the proposed mechanism in a network of spiking neurons, and tested one of its central claims. Results showed that the model was capable of producing behaviour similar to that observed in normal humans, as well as that exhibited during VMPFC damage.     

Pleasures of the brain

How does the brain cause positive affective reactions to sensory pleasure? An answer to pleasure causation requires knowing not only which brain systems are activated by pleasant stimuli, but also which systems actually cause their positive affective properties. This paper focuses on brain causation of behavioral positive affective reactions to pleasant sensations, such as sweet tastes. Its goal is to understand how brain systems generate 'liking,' the core process that underlies sensory pleasure and causes positive affective reactions. Evidence suggests activity in a subcortical network involving portions of the nucleus accumbens shell, ventral pallidum, and brainstem causes 'liking' and positive affective reactions to sweet tastes. Lesions of ventral pallidum also impair normal sensory pleasure. Recent findings regarding this subcortical network's causation of core 'liking' reactions help clarify how the essence of a pleasure gloss gets added to mere sensation. The same subcortical 'liking' network, via connection to brain systems involved in explicit cognitive representations, may also in turn cause conscious experiences of sensory pleasure.     

Neural dynamics of autistic behaviors: cognitive, emotional, and timing substrates

What brain mechanisms underlie autism, and how do they give rise to autistic behavioral symptoms? This article describes a neural model, called the Imbalanced Spectrally Timed Adaptive Resonance Theory (iSTART) model, that proposes how cognitive, emotional, timing, and motor processes that involve brain regions such as the prefrontal and temporal cortex, amygdala, hippocampus, and cerebellum may interact to create and perpetuate autistic symptoms. These model processes were originally developed to explain data concerning how the brain controls normal behaviors. The iSTART model shows how autistic behavioral symptoms may arise from prescribed breakdowns in these brain processes, notably a combination of underaroused emotional depression in the amygdala and related affective brain regions, learning of hyperspecific recognition categories in the temporal and prefrontal cortices, and breakdowns of adaptively timed attentional and motor circuits in the hippocampal system and cerebellum. The model clarifies how malfunctions in a subset of these mechanisms can, through a systemwide vicious circle of environmentally mediated feedback, cause and maintain problems with them all.     

Stress modulation of cognitive and affective processes

This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects.     

The neuropsychology of ventral prefrontal cortex: decision-making and reversal learning

Converging evidence from human lesion, animal lesion, and human functional neuroimaging studies implicates overlapping neural circuitry in ventral prefrontal cortex in decision-making and reversal learning. The ascending 5-HT and dopamine neurotransmitter systems have a modulatory role in both processes. There is accumulating evidence that measures of decision-making and reversal learning may be useful as functional markers of ventral prefrontal cortex integrity in psychiatric and neurological disorders. Whilst existing measures of decision-making may have superior sensitivity, reversal learning may offer superior selectivity, particularly within prefrontal cortex. Effective decision-making on existing measures requires the ability to adapt behaviour on the basis of changes in emotional significance, and this may underlie the shared neural circuitry with reversal learning.     

社会排斥影响跨期决策的心理机制探讨

社会排斥广泛存在于社会生活中, 并对人们的认知、情感、行为等诸多方面产生严重的消极影响。它会损害个体的认知功能, 导致个体不能进行理性的判断和决策。研究发现被排斥的个体在风险决策时倾向于风险寻求。跨期决策和风险决策都与人类的生存和发展息息相关, 但目前并不清楚社会排斥是否以及如何影响跨期决策。因此, 本研究拟从跨期决策的评估和选择两个阶段展开研究, 揭示社会排斥对其的作用机制。并在此基础上, 运用tDCS技术激活社会排斥的调节脑区, 以改善被排斥个体的跨期决策能力。研究结果将揭示人际情境因素与决策者个人因素对跨期决策的联合作用机制, 帮助被排斥者提高跨期决策能力, 提高被排斥者的个人成就和生活质量。     

Self-compassion and responses to negative social feedback: The role of fronto-amygdala circuit connectivity

ABSTRACT

Self-compassion has been shown to have significant relationships with psychological health and well-being. Despite the increasing growth of research on the topic, no studies to date have investigated how self-compassion relates to neural responses to threats to the self. To investigate whether self-compassion relates to threat-regulatory mechanisms at the neural level of analysis, we conducted a functional MRI study in a sample of college-aged students. We hypothesized that self-compassion would relate to greater negative connectivity between the ventromedial prefrontal cortex (VMPFC) and amygdala during a social feedback task. Interestingly, we found a negative correlation between self-compassion and VMPFC-amygdala functional connectivity as predicted; however, this seemed to be due to low levels of self-compassion relating to greater positive connectivity in this circuit (rather than high levels of self-compassion relating to more negative connectivity). We also found significant relationships with multiple subcomponents of self-compassion (Common Humanity, Self-Judgment). These results shed light on how self-compassion might affect neural responses to threat and informs our understanding of the basic psychological regulatory mechanisms linking a lack of self-compassion with poor mental health.     

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。