“冷”/“热”执行功能缺陷影响ADHD儿童核心症状的作用机制

注意缺陷多动障碍(ADHD)是一种以注意缺陷和(或)多动、冲动为核心症状的神经发育障碍,与前额叶发育异常所致的执行功能缺陷密切相关。基于此,从神经-认知-行为的发展途径提出执行功能缺陷可能是认知层面上导致ADHD核心症状的发病机理,其中与背侧前额叶相关的“冷”执行功能缺陷可能是导致注意缺陷核心症状的主导因素,而与腹内侧前额叶相关的“热”执行功能缺陷可能是导致多动、冲动核心症状的主导因素。一方面,“冷”执行功能缺陷主要引起工作记忆表征维持失败、抑制控制能力不足、认知转换困难等方面,这些缺陷进一步导致了个体在注意持续、注意选择和注意转移上受到限制;另一方面,“热”执行功能缺陷则带来厌恶延迟、奖赏加工异常、动机失调等问题,使得个体行为抑制失败,更容易做出冲动性选择,从而表现出多动、冲动等核心症状。未来研究应进一步检验和完善“冷”、“热”执行功能缺陷影响ADHD核心症状的理论模型以及从认知神经层面上提供更多的实证证据,同时还需从生态层面考察“冷”和“热”执行功能缺陷对ADHD核心症状的交互影响,并基于执行功能开发对ADHD核心症状具有个性化、精准化、长效化的干预方案。     

金钱崇拜对个体跨期决策偏好的影响

采用经典跨期选择任务范式,以个体的金钱喜好差异为切入点,通过问卷调查和行为实验考察金钱崇拜对个体跨期决策偏好的影响。结果发现:(1)个体的金钱崇拜水平与其跨期折扣倾向显著负相关;(2)无论跨期决策任务的难易和兑现时间的长短,高金钱崇拜者更倾向于选择较大的延迟奖赏,而低金钱崇拜者更倾向于选择较小的即时奖赏;(3)高、低金钱崇拜者的跨期决策反应时没有明显的差异,但二者的反应时都明显地受到任务难度的影响,即在容易条件下的反应速度显著快些。结果表明,个体的金钱崇拜水平在跨期决策过程中发挥着重要的作用,致使高金钱崇拜者更愿意等待延迟大奖赏的到来。     

不确定性容忍度对跨期选择的影响及其情景依赖性

采用2(不确定性容忍度：高、低)×2(跨期日期：今天/14天、今天/180天)×2(延迟奖赏值：200元、1000元)混合实验设计,探讨不同任务特征下不确定性容忍度对跨期选择的影响。结果表明：跨期日期为180天时,不确定性容忍度主效应边缘显著;不确定性容忍度与延迟奖赏值交互作用显著：在200元时低容忍度个体对延迟奖赏的折扣程度大于高容忍度个体,在1000元时无此效应;跨期日期为14天时,不确定性容忍度的主效应及其与延迟奖赏值交互作用均不显著。这表明,不确定性容忍度对跨期选择存在影响,但这种影响受到跨期日期和延迟奖赏值的调节,具有情景依赖性。     

氟哌啶醇与丙咪嗪交互作用对成本效益决策的影响

本实验采用T迷宫延迟奖赏模型研究多巴胺D2受体拮抗剂氟哌啶醇和5-羟色胺重摄取抑制剂丙咪嗪的交互作用对成本效益决策的影响, 同时探讨了延迟时间对决策的影响。T迷宫两臂分别设置为低成本-低奖赏端和高成本-高奖赏端。实验结果发现：氟哌啶醇能够降低大鼠选择高成本-高奖赏端的次数, 丙咪嗪则能够增加大鼠选择高成本-高奖赏端的次数; 在同时注射这两种药物情况下, 丙咪嗪能够抑制由氟哌啶醇引起的对低成本-低奖赏端的选择倾向。另外, 实验发现, 随延迟时间的增加大鼠选择高成本-高奖赏端的次数相对减少。由此可见, 丙咪嗪能够反转由氟哌啶醇导致的对低成本-低奖赏端的选择倾向, 这可能是由于细胞间5-羟色胺含量的升高部分反转了由多巴胺系统受损导致的行为倾向; 延迟时间的改变可对决策倾向产生逆转, 因此成本的支出即延迟时间也是影响成本效益决策的重要因素。     

未来情景想象对海洛因戒断者跨期决策的影响

大量研究发现海洛因成瘾者在跨期决策中更加偏好即时奖赏,对延迟奖赏具有更高的延迟折扣率。本研究采用延迟折扣任务探讨了未来情景想象对海洛因戒断者跨期决策的影响。实验1结果发现,前测中海洛因戒断组在金钱延迟折扣任务中的曲线下面积(the areas under the curve, AUC)显著小于对照组,而未来情景想象后两组被试的AUC值没有显著差异。而且海洛因戒断组在两种条件的AUC差值显著大于对照组。实验2结果发现,海洛因戒断组在前测的跨类别延迟折扣任务中的AUC值显著小于其未来情景想象后的AUC值。鉴于未来情景想象可以改善海洛因戒断者的跨期决策表现,今后可采用未来情景想象展开针对海洛因成瘾者跨期决策的靶向干预,降低海洛因成瘾者复吸的风险。     

虚拟和真实金钱奖赏幅度对海洛因戒断者风险决策的影响

已有研究表明海洛因成瘾者风险决策能力受损, 但少有研究关注不同幅度金钱奖赏对戒断期海洛因成瘾者风险决策的影响以及这种影响是否会受到金钱奖赏类型的调节。因此, 本研究使用气球模拟风险任务(BART), 通过两个实验探究不同幅度虚拟和真实金钱奖赏对海洛因戒断者风险决策的影响。结果显示, 在虚拟奖赏情景下, 海洛因戒断者未爆破气球按键次数和爆破气球个数均显著大于正常组被试, 以及两组被试在25分奖赏条件下的未爆破气球按键次数和爆破气球个数均显著大于1分奖赏; 而在真实奖赏情景下, 海洛因戒断者未爆破气球按键次数和爆破气球个数均显著小于正常组被试, 以及两组被试在25分奖赏条件下的未爆破气球按键次数和爆破气球个数均显著小于1分奖赏。研究结果表明, 金钱奖赏类型和金钱奖赏幅度会影响被试的风险决策行为。在虚拟奖赏情景下, 两组被试的风险偏好水平随着奖赏幅度的增加显著升高, 但是戒断期海洛因成瘾者的风险偏好水平高于正常组被试; 而在真实奖赏情景下, 两组被试的风险偏好水平随着奖赏幅度的增加显著降低, 同时戒断期海洛因成瘾者的风险偏好水平低于正常组被试。     

不同类型罪犯在爱荷华赌博任务中的决策功能缺陷

采用爱荷华赌博任务(Behcara等人1994年版本)测量了8类共222名在监男性罪犯以及32名普通男性的决策功能, 并运用前景效用学习模型分析了不同类型罪犯在情感决策中的心理功能缺陷。罪犯组选择牌1的比例与控制组没有显著差异, 选择牌2的比例显著高于控制组, 选择牌3和牌4的比例显著低于控制组。暴力犯和涉黑犯对收益和损失都不敏感, 对过去的预期效用折扣很快; 吸毒犯(已戒除)、涉毒犯、盗窃犯和抢劫犯对奖赏加工正常, 对惩罚不敏感; 经济犯选择一致性最低; 性罪犯选择一致性最高。结果表明不同类型罪犯在爱荷华赌博任务中都具有决策功能缺陷, 但他们的决策功能缺陷由不同的心理功能缺陷所致。     

自我损耗、情绪动机对冲动决策的影响

以大学生为被试,探讨自我损耗、情绪动机对冲动决策的影响。采用2×2×2的混合实验设计,组内变量为自我损耗,组间变量为情绪动机方向和强度,使用双任务范式操作自我损耗,使用情绪动机图片启动被试的情绪动机,使用延迟折扣任务的指标k值测量冲动决策。结果发现,高趋近动机的k值大于低趋近动机,高回避动机的k值大于低回避动机。结果表明,自我损耗、情绪动机对冲动决策有明显影响。     

真实和虚拟金钱奖赏影响风险决策行为*

在风险情境下人类如何决策是长久以来心理学和经济学研究中一个极具挑战性的核心问题。众多研究采用真实或虚拟金钱作为奖赏强化物来探索风险决策行为的过程和机制,但对金钱奖赏真实性如何影响决策了解很少。仿真气球冒险任务(BART：Balloon Analogue Risk Task)可以在实验室条件下有效评估个体在真实社会中的风险行为。本研究采用 BART任务,通过两个实验探讨和比较了真实与虚拟金钱奖赏对风险决策行为的影响。实验一的结果发现,与虚拟金钱奖赏相比,真实金钱奖赏情境下的风险决策更容易受上一次决策结果的影响,上一次决策失败会导致被试的风险偏好水平显著降低(平均吹气球的次数显著减少),同时决策失败(气球吹爆)次数也显著减少,提示真实金钱奖赏下有更强的反馈学习效应。实验二重复了实验一的结果,并进一步发现,虚拟金钱奖赏的幅度对被试的风险决策行为没有影响,而真实金钱奖赏的幅度能显著改变被试的风险决策行为,较大幅度的真实金钱奖赏可以显著降低被试的风险偏好水平,但这种奖赏幅度对风险偏好的调控效应只对感觉寻求水平低的被试有效,感觉寻求水平高的被试不受影响。这些发现表明真实与虚拟金钱奖赏对风险决策行为有不同的影响。我们的结果可以用风险决策的后悔理论或齐当别模型来解释。     

不确定性容忍度、损益概率及延迟风险对延迟选择的影响

研究通过两个实验考查了不确定性容忍度及相关变量对延迟选择的影响,其中实验1采用2（不确定性容忍度：高/低）×2（概率水平：高/中）被试间实验设计;研究2将实验任务设定在有延迟风险情景下中等概率水平,采用单因素（不确定性容忍度：高/低）被试间实验设计.实验1结果表明：不确定性容忍度与概率水平存在交互作用：中等概率时,低容忍度个体比高容忍度个体更偏好延迟选择,高概率时,两者的延迟选择无显著差异,都偏好于选择决策.实验2结果表明：在有延迟风险中等概率时,高、低容忍度个体的决策偏好无显著差异,都偏好选择决策.结论：不确定性容忍度对延迟选择存在影响且受概率水平和延迟风险的调节.     

Contributions of the nucleus accumbens and its subregions to different aspects of risk-based decision making

The nucleus accumbens (NAc) has been implicated in mediating different forms of decision making in humans and animals. In the present study, we observed that inactivation of the rat NAc, via infusion of GABA agonists, reduced preference for a large/risky option and increased response latencies on a probabilistic discounting task. Discrete inactivations of the NAc shell and core revealed further differences between these regions in mediating choice and response latencies, respectively. The effect on choice was attributable to reduced win–stay performance (i.e., choosing risky after a being rewarded for a risky choice on a preceding trial). Moreover, NAc inactivation altered choice only when the large/risky option had greater long-term value, in terms of the amount of food that could be obtained over multiple trials relative to the small/certain option. Inactivation of the NAc or the shell subregion also slightly reduced preference for larger rewards on a reward magnitude discrimination. Thus, the NAc seems to play a small role in biasing choice toward larger rewards, but its contribution to behavior is amplified when delivery of these rewards is uncertain, helping to direct response selection toward more favorable outcomes.     

Intact risk-based decision making in rats with prefrontal or accumbens dopamine depletion

The medial prefrontal cortex (mPFC) and the core region of the nucleus accumbens (AcbC) are key regions of a neural system that subserves risk-based decision making. Here, we examined whether dopamine (DA) signals conveyed to the mPFC and AcbC are critical for risk-based decision making. Rats with 6-hydroxydopamine or vehicle infusions into the mPFC or AcbC were examined in an instrumental task demanding probabilistic choice. In each session, probabilities of reward delivery after pressing one of two available levers were signaled in advance in forced trials followed by choice trials that assessed the animal??s preference. The probabilities of reward delivery associated with the large/risky lever declined systematically across four consecutive blocks but were kept constant within four subsequent daily sessions of a particular block. Thus, in a given session, rats need to assess the current value associated with the large/risky versus small/certain lever and adapt their lever preference accordingly. Results demonstrate that the assessment of within-session reward probabilities and probability discounting across blocks were not altered in rats with mPFC and AcbC DA depletions, relative to sham controls. These findings suggest that the capacity to evaluate the magnitude and likelihood of rewards associated with alternative courses of action seems not to rely on intact DA transmission in the mPFC or AcbC.     

Context influences decision-making in boys with attention-deficit/hyperactivity disorder: A comparison of traditional and novel choice-impulsivity paradigms

Attention-deficit/hyperactivity disorder (ADHD) is characterized by an impaired ability to maintain attention and/or hyperactivity/impulsivity. Impulsivity is frequently defined as the preference for small, immediate rewards over larger, delayed rewards, and has been associated with a variety of negative outcomes such as risky behavior and academic difficulty. Extant studies have uniformly utilized the traditional paradigm of presenting two response choices, which limits the generalization of findings to scenarios in which children/adolescents are faced with dichotomous decisions. The current study is the first to examine the effect of manipulating the number of available response options on impulsive decision-making in boys with and without ADHD. A total of 39 boys (ADHD = 16, typically developing [TD] = 23) aged 8–12 years completed a traditional two-choice impulsivity task and a novel five-choice impulsivity task to examine the effect of manipulating the number of choice responses (two vs five) on impulsive decision-making. A five-choice task was utilized as it presents a more continuous array of choice options when compared to the typical two-choice task, and is comparable given its methodological similarity to the two-choice task. Results suggested that boys with ADHD were significantly more impulsive than TD boys during the two-choice task, but not during the five-choice task. Collectively, these findings suggest that ADHD-related impulsivity is not ubiquitous, but rather dependent on variation in demands and/or context. Further, these findings highlight the importance of examining ADHD-related decision-making within the context of alternative paradigms, as the exclusive utilization of two-choice tasks may promote inaccurate conceptualizations of the disorder.     

Impulsive choice and pre‐exposure to delays: iv. effects of delay‐ and immediacy‐exposure training relative to maturational changes in impulsivity

Impulsive choice describes preference for smaller, sooner rewards over larger, later rewards. Excessive delay discounting (i.e., rapid devaluation of delayed rewards) underlies some impulsive choices, and is observed in many maladaptive behaviors (e.g., substance abuse, gambling). Interventions designed to reduce delay discounting may provide therapeutic gains. One such intervention provides rats with extended training with delayed reinforcers. When compared to a group given extended training with immediate reinforcers, delay‐exposed rats make significantly fewer impulsive choices. To what extent is this difference due to delay‐exposure training shifting preference toward self‐control or immediacy‐exposure training (the putative control group) shifting preference toward impulsivity? The current study compared the effects of delay‐ and immediacy‐exposure training to a no‐training control group and evaluated within‐subject changes in impulsive choice across 51 male Wistar rats. Delay‐exposed rats made significantly fewer impulsive choices than immediacy‐exposed and control rats. Between‐group differences in impulsive choice were not observed in the latter two groups. While delay‐exposed rats showed large, significant pre‐ to posttraining reductions in impulsive choice, immediacy‐exposed and control rats showed small reductions in impulsive choice. These results suggest that extended training with delayed reinforcers reduces impulsive choice, and that extended training with immediate reinforcers does not increase impulsive choice.     

Emotion Dysregulation and Emotional Impulsivity among Adults with Attention-Deficit/Hyperactivity Disorder: Results of a Preliminary Study

Recent reviews argue that emotion dysregulation is an important feature of attention-deficit/hyperactivity disorder (ADHD) and involves a failure to inhibit negative emotions that leads to negative affectively-driven impulsive behavior (i.e., emotional impulsivity). The goal of the current study was to assess (a) whether emotion dysregulation and emotional impulsivity was higher in a group of adults diagnosed with ADHD and (b) if the relationship between core ADHD symptoms (i.e., inattention and hyperactivity-impulsivity) and emotional impulsivity is mediated by emotion dysregulation symptoms. A group of adults with (n?=?18) and without (n?=?23) ADHD completed measures of core ADHD symptoms, emotion dysregulation, and emotional impulsivity. A series of one-way analyses of covariance indicated significant between-group differences in emotion dysregulation and emotional impulsivity when current depression and oppositional defiant disorder ratings were covaried. In addition, the relationship between ADHD symptoms and emotional impulsivity was mediated by emotion dysregulation symptoms. These findings suggest that emotion dysregulation and emotional impulsivity are higher in adults diagnosed with ADHD and that emotion dysregulation symptoms have predictive value beyond core ADHD symptoms.     

Comparative neuropsychology of adult obsessive-compulsive disorder and attention deficit/hyperactivity disorder: Implications for a novel executive overload model of OCD

Research implicates frontostriatal pathophysiology in both attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Nevertheless, ADHD is characterized with frontostriatal hypoactivity and OCD with hyperactivity. Furthermore, both disorders seem to lie on opposite ends of a clinical impulsive-compulsive continuum. While never having directly been compared, and despite these differences, OCD and ADHD appear to share similar neuropsychological impairments especially in executive functions. This study aimed at comparing adults with OCD and adults with ADHD on neuropsychological measures and behavioural impulsivity and OC measures. Thirty OCD, 30 ADHD, and 30 matched healthy control (HC) participants were administered a comprehensive neuropsychological battery and completed several questionnaires. The groups were compared on all neuropsychological and clinical measures and correlations between neuropsychological and clinical symptoms were computed. The ADHD and OCD groups performed more poorly than HC on all neuropsychological domains and most domain subtests. The ADHD group reported significantly higher impulsivity than the OCD group. OCD patients did not differ from HC on behavioural impulsivity. A unique dissociation was found between impulsivity and response inhibition where both clinical groups showed similar response inhibition deficit, but differed significantly on impulsivity. Moreover, a negative association between OC symptoms and response inhibition and a bias in self-perception of impulsivity was found only in the OCD group. We propose an executive overload model of OCD that views neuropsychological impairments in OCD as an epiphenomenon, according to which continuous attempts to control automatic processes are associated with obsessive thoughts overflow that causes an overload on the executive system.     

奖惩对注意缺陷多动障碍儿童情感决策的影响

采用简化版儿童赌博任务,其中操纵了奖励和惩罚的强度,探察两种亚型（注意缺陷型和混合型）ADHD儿童的情感决策能力,同时采集儿童在任务中的皮肤电活动以探析ADHD儿童在情感决策中的生理机制。结果发现,在不同的奖惩强度下,ADHD儿童情感决策模式不同,在即刻奖励条件下,ADHD儿童情感决策的能力明显弱于正常对照组儿童,倾向于不利选择,所产生的预测性皮电振幅也明显低于正常对照组;在即刻惩罚条件下,ADHD儿童的情感决策能力未见异常。两种亚型ADHD儿童的表现模式相似。上述结果证明,ADHD儿童仅存在对奖励的异常敏感性,并确实影响了其决策能力,而其回避惩罚的能力正常。两种亚型ADHD儿童存在的问题相似     

Theta synchronizes the activity of medial prefrontal neurons during learning

Memory consolidation is thought to involve the gradual transfer of transient hippocampal-dependent traces to distributed neocortical sites via the rhinal cortices. Recently, medial prefrontal (mPFC) neurons were shown to facilitate this process when their activity becomes synchronized. However, the mechanisms underlying this enhanced synchrony remain unclear. Because the hippocampus projects to the mPFC, we tested whether theta oscillations contribute to synchronize mPFC neurons during learning. Thus, we obtained field (LFP) and unit recordings from multiple mPFC sites during the acquisition of a trace-conditioning task, where a visual conditioned stimulus (CS) predicted reward delivery. In quiet waking, the activity of mPFC neurons was modulated by theta oscillations. During conditioning, CS presentation caused an increase in mPFC theta power that augmented as the CS gained predictive value for reward delivery. This increased theta power coincided with a transient theta phase locking at distributed mPFC sites, an effect that was also manifest in the timing of mPFC unit activity. Overall, these results show that theta oscillations contribute to synchronize neuronal activity at distributed mPFC sites, suggesting that the hippocampus, by generating a stronger theta source during learning, can synchronize mPFC activity, in turn facilitating rhinal transfer of its activity to the neocortex.     

Behavioral variability in SHR and WKY rats as a function of rearing environment and reinforcement contingency.

The spontaneously hypertensive rat (SHR) may model aspects of human attention deficit hyperactivity disorder (ADHD). For example, just as responses by children with ADHD tend to be variable, so too SHRs often respond more variably than do Wistar-Kyoto (WKY) control rats. The present study asked whether behavioral variability in the SHR strain is influenced by rearing environment, a question related to hypotheses concerning the etiology of human ADHD. Some rats from each strain were reared in an enriched environment (housed socially), and others were reared in an impoverished environment (housed in isolation). Four groups--enriched SHR, impoverished SHR, enriched WKY, and impoverished WKY--were studied under two reinforcement contingencies, one in which reinforcement was independent of response variability and the other in which reinforcement depended upon high variability. The main finding was that rearing environment did not influence response variability (enriched and impoverished subjects responded similarly throughout). However, rearing environment affected body weight (enriched subjects weighted more than impoverished subjects) and response rate (impoverished subjects generally responded faster than enriched subjects). In addition, SHRs tended to respond variably throughout the experiment, whereas WKYs were more sensitive to the variability contingencies. Thus, behavioral variability was affected by genetic strain and by reinforcement contingency but not by the environment in which the subjects were reared.     

Observational learning in mice can be prevented by medial prefrontal cortex stimulation and enhanced by nucleus accumbens stimulation

The neural structures involved in ongoing appetitive and/or observational learning behaviors remain largely unknown. Operant conditioning and observational learning were evoked and recorded in a modified Skinner box provided with an on-line video recording system. Mice improved their acquisition of a simple operant conditioning task by observational learning. Electrical stimulation of the observer's medial prefrontal cortex (mPFC) at a key moment of the demonstration (when the demonstrator presses a lever in order to obtain a reward) cancels out the benefits of observation. In contrast, electrical stimulation of the observer's nucleus accumbens (NAc) enhances observational learning. Ongoing cognitive processes in the demonstrator could also be driven by electrical stimulation of these two structures, preventing the proper execution of the ongoing instrumental task (mPFC) or stopping pellet intake (NAc). Long-term potentiation (LTP) evoked in these two cortical structures did not prevent the acquisition or retrieval process--namely, mPFC and/or NAc stimulation only prevented, or modified, the ongoing behavioral process. The dorsal hippocampus was not involved in either of these two behavioral processes. Thus, both ongoing observational learning and performance of an instrumental task require the active contribution of the mPFC and/or the NAc.