具身认知视角的饮食消费行为——基于心理模拟“具身”方式

随着具身认知理论的发展, 基于心理模拟“具身”方式的饮食消费行为研究得到了一些新颖、有趣的研究结果, 为过食与肥胖、食品营销等问题的解决提供了新视角。心理模拟既能促进进食也能抑制进食; 心理模拟容易性因素与动机性因素是影响心理模拟程度的两大类主要前因变量; 未来需要进一步探索心理模拟的容易性因素与动机性因素、心理模拟提高消费欲望与产生腻厌反应的边界条件, 以及利用心理模拟探讨肥胖高危人群——高奖赏敏感性个体过食的深层次内在机制等。     

具身认知视角的饮食消费行为——基于心理模拟“具身”方式

随着具身认知理论的发展,基于心理模拟"具身"方式的饮食消费行为研究得到了一些新颖、有趣的研究结果,为过食与肥胖、食品营销等问题的解决提供了新视角。心理模拟既能促进进食也能抑制进食;心理模拟容易性因素与动机性因素是影响心理模拟程度的两大类主要前因变量;未来需要进一步探索心理模拟的容易性因素与动机性因素、心理模拟提高消费欲望与产生腻厌反应的边界条件,以及利用心理模拟探讨肥胖高危人群——高奖赏敏感性个体过食的深层次内在机制等。     

冲动性对吗啡诱导的条件性位置偏爱及行为敏感化的影响

许多研究显示, 冲动性与尼古丁、可卡因、海洛因等药物成瘾显著相关, 但它对吗啡成瘾的影响尚未见到报道。本实验考察冲动性对吗啡诱导的条件性位置偏爱及行为敏感化的影响。实验采用延迟奖赏模型将大鼠的冲动性区分为高、中、低三个水平, 每个水平设置吗啡处理组和盐水处理组。结果发现：动物对吗啡诱导的条件性位置偏爱的程度表现为低冲动组>中冲动组>高冲动组, 并且中、低冲动组动物形成了条件性位置偏爱而高冲动组没有形成这种偏爱; 在行为敏感化表达期, 与相应的盐水组比较, 高、中冲动组动物的吗啡运动激活效应显著, 而低冲动组没有达到显著水平。这些结果提示, 条件性位置偏爱任务中, 动物的冲动性越高, 吗啡的强化效应越低; 行为敏感化任务中, 动物的冲动性越高, 吗啡的运动激活效应越高。由此可见, 动物的冲动性对吗啡诱导的条件性位置偏爱及行为敏感化的影响存在差异。     

多巴胺对动物冲动性的影响

冲动性是注意缺陷障碍、物质成瘾以及病理性赌博等常见精神疾病的主要症状, 已经成为人们日益关注的焦点。研究发现, 前额叶–纹状体神经回路多巴胺参与了冲动性的调节, 但是研究结果并不一致, 多巴胺在冲动性中发挥的作用, 可能会受到三个不同因素的影响。首先, 冲动性具有多维度特征, 多巴胺对冲动的多种亚结构的作用存在差异; 其次, 多巴胺可以通过多个脑区以及与其他递质系统的交互作用影响冲动性; 最后, 多巴胺在调节冲动性的过程中可能还受到多种变量的影响, 如个体差异、环境线索等。     

肥胖成因的解释——基于食物奖赏研究的视角

肥胖的形成和发展受生物、心理和社会因素的共同作用,其中食物奖赏对肥胖的产生有重要的作用。食物是一种自然奖赏,它指机体天生对食物的渴望和依赖。食物奖赏包括"wanting"、"liking"以及"learningreinforcement"三个成分,每个成分由相应的神经通路表征。食物奖赏调控机体的摄食行为并以此调控体重变化。目前,关于肥胖与食物奖赏关系的理论模型主要有刺激—敏感化理论、奖赏过度理论以及奖赏不足理论。采用横断面设计、前瞻研究设计和纵向被试内重复测量设计,使用食物图片线索和直接给予美味奶昔的技术方法,人类脑成像研究从不同侧面为以上三个理论模型提供了证据。除此之外,食物奖赏还受基因的调控。目前,研究者关注较多的是多巴胺D2受体基因Taq IA rs1800497的多态性和FTO基因rs9939609的多态性对食物奖赏及体重改变的调控。     

反馈相关负波：一种抑郁症的生物标记物

反馈相关负波(feedback-related negativity, FRN)是一种反映个体奖赏敏感性的脑电成分; 而抑郁症患者的特征之一是奖赏敏感性的减弱。大量横向研究发现了重度抑郁症患者(major depressive disorder, MDD)及有患抑郁症风险群体的FRN异常; 另外, 纵向研究发现FRN的异常能够预测青春期抑郁发作及抑郁症状发展, 压力、睡眠等因素在其中起调节作用。这提示FRN可能在对抑郁症的诊断及分型、抑郁高危群体的筛查及干预等方面具有潜在价值。目前关于FRN的心理功能依然存在一些争议, 在未来的研究中应该进一步明确FRN的功能和测量方法, 并探明抑郁症的异质性和共病对FRN的作用, 也应关注老年人群体中FRN与抑郁症的关系。     

长期戒断海洛因成瘾者冲动性相关脑区的结构及功能特征

冲动性是药物成瘾者的典型特征, 它既包含了抑制控制成瘾者药物使用的力量, 也包含驱动成瘾者使用药物的成分, 两者不平衡导致冲动性用药行为。海洛因成瘾者本身具有冲动性人格特质, 长时间的海洛因使用又会造成成瘾者冲动性相关的大脑结构与功能的异常。目前难以确定戒断后, 冲动性及相关的大脑结构与功能是否还呈异常状态。本研究采用基于体素的形态学分析、低频振幅、局部一致性和功能连接方法, 以35例海洛因成瘾戒断者和无任何成瘾史的健康个体26人为研究对象, 探索在长期戒断后, 海洛因成瘾者与其冲动性相关的驱动、控制系统脑网络的结构和功能情况。结果显示, 相比对照组, 戒断组灰质总体积及右内侧额上回的灰质体积显著减小, 右侧颞中回和左内侧旁扣带回的灰质体积随用药总量的增加而降低; 右侧眶部额下回与尾状核功能连接显著增强, 右侧颞中回和左侧中央前回功能连接显著降低; 右眶额中回的ReHo值、右眶额下回和左海马体的ALFF值比对照组显著更低, 而右中央后回的ReHo值显著更高。这些脑区的状况与冲动性的神经基础相吻合, 说明海洛因成瘾戒断者在戒断44个月, 奖赏、凸显、习惯性行为等网络系统仍然呈现异常状态, 且与成瘾药物使用总量有关。这些异常可能是成瘾冲动性的驱动力的神经基础, 可以作为解释成瘾者戒断后容易复吸的因素之一。     

冲动性对不同成瘾行为发展的调控及其神经机制

近年来越来越多的研究证据提示, 个体冲动性在成瘾疾患发生发展机制中具有关键作用, 可能成为成瘾行为的潜在易感标记以及早期识别和干预的重要靶点, 但冲动性对不同成瘾行为变化发展的调控机制尚不明确。项目拟综合跨成瘾谱系比较、纵向追踪设计、冲动行为干预等研究途径, 采用人格测量、神经认知、神经影像等技术, 首先比较尼古丁依赖者与网络游戏成瘾者的冲动性结构及其在前额叶–纹状体环路的结构功能改变; 然后采用混合分组设计筛选出具有高低冲动性的非成瘾青少年进行连续追踪研究, 考察冲动性对尼古丁依赖与网络游戏成瘾的预测效力; 并采用认知行为训练, 对吸烟成瘾者与网络游戏成瘾者进行冲动干预, 考察行为干预对冲动性水平及前额叶–纹状体环路功能的改变, 以及对不同成瘾行为发展的抑制后效。旨在探索冲动性作为成瘾的潜在易感标记及干预靶点的效力。     

正念训练对冲动性不同要素的影响：基于双加工理论

正念是指对当下身心体验不带有评判地觉察。基于双加工理论,以正念为核心的训练对个体冲动性不同要素均具有明显干预效果。一方面,有助于降低因情感系统引发的冲动驱力：通过调整个体的奖赏评估与预期,缓和诱发冲动的压力与负性情绪反应,减弱自动化反应的联结和强度;另一方面,提升个体由认知控制系统调节的冲动控制力：增强个体的认知控制和行为抑制能力。由于冲动性驱动因素和控制因素二者加工时序的先后差异和作用方向对抗性特点,正念训练促进两类要素的积极交互影响,缩小冲动性“驱动”与“控制”力量之间的不平衡,为个体更好地回应自身反应与外界刺激提供了有利缓冲,是降低个体冲动性的有效干预手段。     

乳腺癌患者减重干预的研究进展

目前研究认为,肥胖是乳腺癌的预后不良因素之一,肥胖可能增加女性乳腺癌的发病率和病死率,降低乳腺癌手术、化疗及放疗的治疗效果。减重干预是减轻体重、改善肥胖的有效途径。近年来,研究发现减重有助于延缓肥胖小鼠乳腺癌的进展与转移,可能降低肥胖者乳腺癌的发病率与病死率,调节肥胖乳腺癌患者的血清标志物水平,并对肥胖乳腺癌患者的生命质量、饮食行为、生活方式等产生积极影响。减重干预有望成为肥胖的乳腺癌长期存活者的重要辅助治疗手段。     

Reward, dopamine and the control of food intake: implications for obesity

The ability to resist the urge to eat requires the proper functioning of neuronal circuits involved in top-down control to oppose the conditioned responses that predict reward from eating the food and the desire to eat the food. Imaging studies show that obese subjects might have impairments in dopaminergic pathways that regulate neuronal systems associated with reward sensitivity, conditioning and control. It is known that the neuropeptides that regulate energy balance (homeostatic processes) through the hypothalamus also modulate the activity of dopamine cells and their projections into regions involved in the rewarding processes underlying food intake. It is postulated that this could also be a mechanism by which overeating and the resultant resistance to homoeostatic signals impairs the function of circuits involved in reward sensitivity, conditioning and cognitive control.     

Impulse and Self-Control From a Dual-Systems Perspective

ABSTRACT— Though human beings embody a unique ability for planned behavior, they also often act impulsively. This insight may be important for the study of self-control situations in which people are torn between their long-term goals to restrain behavior and their immediate impulses that promise hedonic fulfillment. In the present article, we outline a dual-systems perspective of impulse and self-control and suggest a framework for the prediction of self-control outcomes. This framework combines three elements that, considered jointly, may enable a more precise prediction of self-control outcomes than they do when studied in isolation: impulsive precursors of behavior, reflective precursors, and situational or dispositional boundary conditions. The theoretical and practical utility of such an approach is demonstrated by drawing on recent evidence from several domains of self-control such as eating, drinking, and sexual behavior.     

Evaluating Eve: visceral states influence the evaluation of impulsive behavior

Impulsive behavior is a common source of stigma. The authors argue that people often stigmatize impulsive behavior because they fail to appreciate the influence visceral impulses have on behavior. Because people tend to underestimate the motivational force of cravings for sex, drugs, food, and so forth, they are prone to stigmatize those who act on these impulses. In line with this reasoning, in 4 studies, the authors found that participants who were in a cold state (e.g., not hungry) made less favorable evaluations of a related impulsive behavior (impulsive eating) than did participants who were in a hot state (e.g., hungry). This empathy gap effect was tested with 3 different visceral states--fatigue, hunger, and sexual arousal--and was found both when participants evaluated others' impulsive behavior (Studies 1 & 2) and when participants evaluated their own impulsive behavior (Study 3). Study 3 also demonstrated that the empathy gap effect is due to different perceptions of the strength of the visceral state itself. Finally, Study 4 revealed that this effect is state specific: Hungry people, for example, evaluated only hunger-driven impulses, and not other forms of impulse, more favorably.     

Time preferences in long-tailed macaques (Macaca fascicularis) and humans (Homo sapiens)

Rosati et al. (Curr Biol 17(19):1663–1668, 2007) found in a self-control test in which choice was between a smaller, immediately delivered food and a larger, delayed food, that chimpanzees preferred the larger reward (self-control); humans, however, preferred the smaller reward (impulsivity). They attributed their results to a species difference in self-control. In Experiment 1, monkeys (long-tailed macaques) were exposed to a self-control task in two conditions: where the food was hidden under differently colored bowls and where it was visible. When these two conditions were compared, choice shifted from greater preference for the impulsive alternative in the hidden condition to greater preference for the self-control alternative in the visible condition. Additionally, in both conditions, preference shifted from self-control to impulsivity over sessions. These results were explained in terms of the reversed-contingency effect (a propensity to reach for more over less when rewards are visible) and not to a capacity for self-control. In Experiment 2, humans that demonstrated preference for more over less in choice preferred the impulsive alternative when choice to either alternative was followed by the same intertrial interval—a preference that accelerates trial rates relative to preference of the self-control alternative. When trial rates were equated so that neither choice accelerated session’s end, humans demonstrated self-control. These results suggest that Rosati et al.’s demonstration of impulsivity in humans was due to participants’ desire to minimize session time.     

前额叶的无创神经干预对饮食控制的影响:基于rTMS和tDCS研究的综述

饮食控制缺陷可导致超重、肥胖和饮食失调。已有研究表明,肥胖和饮食失调者在前额叶认知控制神经环路上存在缺陷。无创神经干预-经颅直流电刺激(t DCS)和重复经颅磁刺激(r TMS)-通过调节前额叶皮层兴奋性来提高饮食控制能力,改善饮食失调症状。未来的研究应考虑不同刺激参数和刺激位点下的干预效应,融合其他神经生理技术考察无创神经干预改善饮食控制的作用机制,考虑个体差异性并结合客观的行为范式进行探究。     

Preference reversals with food and water reinforcers in rats

Rats were given a choice between a smaller, immediately available reward and a larger reward available after a delay. In one phase, the reward was food and in another phase, the reward was water. Constant delays were added between the choice presentation and the delivery of the reward alternatives. As the time between choice and reward delivery increased from 0 to 25 s, all rats (except one in the water phase) reversed their preference from the smaller, sooner alternative to the larger, later alternative. These findings extend the generality of the preference-reversal animal model to qualitatively different reinforcers. Furthermore, the presence of both impulsive and self-control choices within the same animal is consistent with the view that self-control may be understood as choice behavior, and that species differences in self-control may be differences in degree, not kind.     

情绪对饮食行为的影响

人类的饮食行为受到诸多因素的影响, 包括生理因素、心理因素及社会文化因素等, 其中情绪对饮食行为的影响日益受到研究者的重视, 这种影响一般表现为摄入量的多少和食物(热量)的选择。通过探讨不同情绪下临床和非临床个体食物摄入量的表现, 总结发现消极情绪导致个体暴饮暴食的可能更大。积极情绪影响下的饮食行为的研究结果则存在分歧: 生理角度解释为积极情绪能够促进个体的享乐机制, 导致进食行为增加; 而自我控制理论则认为积极情绪增加了个人资源以抵制美食诱惑。此外, 进一步探讨了情绪影响下饮食行为的神经生理机制。未来在饮食相关的临床研究和治疗上, 需要对情绪影响下的饮食行为有更深入的神经机制方面的探究。     

自我损耗促进冲动决策：来自行为和ERPs的证据

该研究以自我控制资源模型为理论框架, 采用行为实验和ERPs技术考察自我损耗对冲动决策的影响。实验1采用Stroop任务操纵自我控制资源并采用延迟折扣任务考察被试的决策冲动性, 实验2采用同样的实验任务并同时采用ERPs技术记录高、低自我损耗者在随后决策任务中的脑电成分。行为结果发现, 在控制心境、特质自我控制水平以及风险偏好等无关变量后, 高损耗者比低损耗者在延迟折扣任务上的折扣程度更大。ERPs结果发现, 不论延迟金额大小, 高损耗者在左侧额区诱发的N1波幅显著小于低损耗者; 高损耗者在右半球诱发的P2波幅显著大于低损耗者。研究表明, 自我损耗抑制决策早期左侧额区的激活水平, 个体因而无法识别冲突以及抵制即时满足的诱惑, 这促使他们采用直觉启发式进行决策, 最终导致冲动决策的产生。     

The allure of forbidden food: On the role of attention in self-regulation

The aim of the present studies was to examine the impact of food cues on restrained eaters’ attention for food. Previous research has shown that restrained eaters spontaneously activate hedonic thoughts in response to palatable food cues, and that such food cues also lead them to inhibit their dieting goal. We argue that as a consequence, restrained eaters’ selective attention will automatically be drawn towards hedonically relevant food items. Consistent with our expectations, the results of two studies revealed that restrained eaters, but not unrestrained eaters, displayed an attentional bias for hedonically rated food items when they had been pre-exposed to food cues. However, this attentional bias did not occur when restrained eaters were primed with the concept of dieting, thereby rendering the regulation of eating behavior more successful. These findings are discussed in the context of implicit processes in self-regulation.     

Building blocks of self-control: increased tolerance for delay with bundled rewards

Impulsive choice can be defined as temporary preference for a smaller-sooner reward (SS) over a larger-later reward (LL). Hyperbolic discounting implies that impulsive choices will occur less when organisms choose between a series of SSs versus LLs all at once than when they choose between single SS versus LL pairs. Eight rats were exposed to two conditions of an intertemporal choice paradigm using sucrose solution as reward. In both conditions, the LL was 150 microl delayed by 3 s, while the SS was an immediate reward that ranged from 25-150 microl across sessions. Preference for the LL was greater when the chosen reward was automatically delivered three times in succession (bundled) than when it was chosen singly and delivered after each choice. For each of the 8 rats, the estimated SS amount that produced indifference was higher in the bundled condition than in the single condition. Because bundling in humans may be based on the perception that one's current choice is predictive of future choices, the data presented here may demonstrate an important building block of self-control.