氟哌啶醇干扰决策过程中前扣带回神经元的放电活动

运用在体多通道神经元放电同步记录技术, 观察和记录大鼠在完成T-迷宫成本效益决策任务时前扣带回神经元放电和局部场电位的变化及氟哌啶醇对此的改变, 在细胞水平上探讨前扣带回在决策中的作用以及多巴胺递质系统对决策的作用机制。结果显示, 经过一段时间的训练, 10只大鼠中有8只偏好高付出-高奖赏端, 且在选择高付出-高奖赏端时的神经元放电频率要显著高于选择低付出-低奖赏端时的频率, 同时局部场电位也呈现出事件相关性; 腹腔注射多巴胺受体拮抗剂氟哌啶醇后, 大鼠不再偏好高付出-高奖赏端, 对该端的选择显著减少, 而对低付出-低奖赏端的选择显著增加, 且神经元的放电频率和局部场电位显著降低, 神经元放电和局部场电位的特征性也消失。研究提示, 前扣带回和多巴胺在努力相关决策任务中有着至关重要的作用。     

新颖寻求特质对药物成瘾易感性的影响及其机制

新颖寻求特质是个体对新颖刺激或潜在的奖赏线索表现出愉悦或兴奋的先天倾向, 并且这种先天倾向会导致个体为寻求潜在的奖赏进行频繁的探索性活动。众多研究表明, 新颖寻求水平高的个体药物成瘾易感性高。多巴胺、5-羟色胺、谷氨酸、γ-氨基丁酸、胆囊收缩素、成纤维细胞生长因子及皮质酮可能参与了新颖寻求特质影响药物成瘾易感性的过程。未来, 仍需对新颖寻求特质影响药物成瘾易感性的神经生物学机制进行深入研究。     

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。     

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。     

不同特质自控者在跨期选择中自我损耗后效的差异

摘要 自我控制在跨期选择中起着重要的作用,个体自我控制资源损耗(简称自我耗损)会影响随后的决策行为。本研究利用双任务范式考察了自我损耗对不同特质自控者跨期选择影响差异。结果发现,自我损耗使低自控者在跨期选择中更倾向于选择较小即时奖赏,而对高自控者的跨期选择倾向没有显著影响。这些结果说明,状态自控对不同特质自控个体跨期选择的影响明显不同,本研究为不同自控特质个体更好地进行跨期选择提供一定的理论依据。     

建议者选择及其中的自我—他人决策差异

基于社会认知的热情-能力模型,探讨了当面临高热情-低能力和高能力-低热情的建议者时,人们会如何选择以及这种选择中的自我-他人决策差异.实验1探讨为自己和为他人选择之间的差异;实验2探讨为自己和建议他人选择之间的差异.结果表明:(1)人们倾向为自己选择高热情-低能力建议者,为他人选择高能力-低热情建议者;(2)为自己选择...     

不确定性容忍度对模糊决策中决策偏好的影响及其情景依赖性*

研究以Ellsberg选瓶任务为决策材料,探讨了不同任务特征下个体不确定性容忍度对模糊决策中决策偏好的影响。结果发现,获益情景下:高概率时高、低容忍度个体对模糊选项的选择无显著差异,均偏好模糊规避;中概率时低容忍度个体比高容忍度个体表现出更低程度的模糊规避,前者倾向于模糊中立,后者倾向于模糊规避;低概率时两者对模糊选项的选择无显著差异,均倾向于模糊中立。损失情景下:高概率时两者对模糊选项的选择无显著差异,均倾向于模糊寻求;中概率时低容忍度比高容忍度个体更偏好模糊寻求,前者倾向于模糊寻求,后者倾向于模糊中立;低概率时两者对模糊选项的选择无显著差异,均倾向于模糊规避。这表明,不确定性容忍度对模糊决策偏好产生作用,但这种作用会受到损益概率和损益结果的影响,具有情景依赖性。     

高中生选科的自我-他人决策差异：预期内疚的作用

本研究首次探讨高中生选科的自我-他人决策差异。结果发现：（1）当科目难度与兴趣存在冲突时,个体倾向于为自己选择低难度低兴趣科目,而为他人选择高难度高兴趣科目;（2）自我-他人决策差异存在程度效应：为近的社会距离他人（朋友）选科时自我-他人决策差异缩小;（3）预期内疚在高中生选科的自我-他人决策差异中起中介作用：相较于为自己选科,为陌生人选择低难度低兴趣科目诱发更高的预期内疚,从而降低其为陌生人选择低难度低兴趣科目的偏好。这些发现拓展了自我-他人决策差异的研究范畴,对家长、学校和教育咨询公司的选科指导具有一定的参考价值。     

风险决策的神经机制:基于啮齿类动物研究

风险决策是在不同选项的结果确定、并且结果出现的概率已知情况下的决策。啮齿类风险决策模型研究发现前额皮层-杏仁核-伏隔核神经环路联系是决定风险决策的选择倾向的关键。前额皮层中的眶额皮层和内侧前额皮层参与风险决策的策略形成和策略转换有关;而皮层下核团中的杏仁核、腹侧纹状体的伏隔核等结构参与策略保持、价值判断,影响决策偏向和行动强度;眶额皮层、伏隔核神经元和多巴胺神经元编码风险决策过程中的概率、风险等因素;此外,多巴胺等单胺类神经递质及受体在风险决策中有复杂的作用。     

提示潜在机会成本对男性海洛因戒断者跨期决策的改善

由于物质成瘾者的跨期决策缺陷在成瘾行为发生、发展及戒断预后中的重要作用,其已成为成瘾研究中的一个靶向干预目标。研究旨在检验提示潜在机会成本能否有效改善男性海洛因戒断者的跨期决策。两个实验分别选取男性海洛因戒断者30名与27名,让其在提示潜在机会成本和未提示潜在机会成本两种决策条件下,分别完成金钱跨期决策任务与海洛因-金钱跨类别延迟折扣任务。结果发现,提示潜在机会成本可以显著减少男性海洛因戒断者在金钱跨期决策任务中选择即时金钱奖赏的数量,但未能显著降低其在海洛因-金钱跨类别延迟折扣任务中的延迟折扣水平。研究结果表明,提示潜在机会成本可以改善男性海洛因戒断者在金钱跨期决策中的短视倾向,但无法改善其在海洛因-金钱跨类别跨期决策中的短视倾向。     

Reduced spiking in entorhinal cortex during the delay period of a cued spatial response task

Intrinsic persistent spiking mechanisms in medial entorhinal cortex (mEC) neurons may play a role in active maintenance of working memory. However, electrophysiological studies of rat mEC units have primarily focused on spatial modulation. We sought evidence of differential spike rates in the mEC in rats trained on a T-maze, cued spatial delayed response task. Animals begin at the base of the T-maze where a 1-sec white noise and visual light cue are presented on the left or right side of the maze. Rats are rewarded for responding toward the cued direction. In correct trials, we observed decreased spike rates during the delay period, the time interval between cue presentation and reward delivery. Firing-rate histograms show significant decreases during the delay period compared to 5-sec windows from both pre-cue and post-reward periods. We analyzed how running speed and trajectory specificity correlated to spike rate. Twice as many cells were responsive to cue alone compared to running speed. Trajectory specificity did not relate significantly to firing rate. Decreased spike rate may reflect active maintenance in other structures inhibiting mEC. Alternately, the reduction may reflect decreases in background activity during enhanced attention and cholinergic modulation. Lastly, animals often ran through the T-maze choice-point with varying speed. We calculated the spatial posterior probability density from spike rates during these choice-point passes. Slow passes through the choice point were characterized by greater probability of decoding to the reward locations on correct trials compared to quick passes on the maze consistent with similar "look-ahead" properties previously reported in the hippocampus and ventral striatum.     

Learning of a T-maze by rat pups when contact with the mother is either permitted or denied

Mother–pup interactions constitute an important component of environmental stimulation of the offspring during the neonatal period. Employing maternal contact as either a positive reinforcer or, its denial, as a frustrative, non-rewarding stimulus, we developed a novel experimental paradigm involving learning by rat neonates of a T-maze. When trained under the reward of maternal contact during postnatal days 10–13 Wistar rat pups learned the choice leading to the mother in a T-maze. When tested 2 h later, in the absence of the mother, pups showed a clear preference for the arm of the T-maze leading to the position of the mother during training. Furthermore, pups receiving the expected reward of maternal contact had higher numbers of c-Fos immunopositive cells in the dorsal striatum compared to either naïve or pups denied the expected reward. The above behavioral and cellular results indicate that pups receiving the expected reward developed a procedural-like memory. When trained under frustrative non-reward pups learned to make the correct choice in the T-maze, albeit less efficiently than pups receiving the expected reward. Following this training condition c-Fos immunohistochemistry revealed increased activation of the CA1 area of the hippocampus and the orbitofrontal cortex. Expression of the information learned by the pups denied the expected reward was contingent upon the presence of the mother in the experimental setup in exactly the same configuration as during the training.     

Scaling Incentives: Determining Preference and Indifference in 8- to lO-Year-Old Girls

The present study adopted procedures similar to those used by Logan (1965) to determine choice behavior in children. The objective was to provide an improved methodology in delay-of-gratification studies, thus avoiding the problems associated with scaling different kinds of rewards, and to provide approximate functions relating a delay-of-token reward to choice behavior. Thus, 7 girls aged 8 to 10 years were exposed to a choice paradigm in which a larger reward (2 tokens) was pitted against a smaller reward (1 token); access to these rewards was delayed a certain period of time. The results of this experiment showed that as the delay of the larger reward increased, preference for the smaller reward increased in an orderly fashion. The finding that delay shifted preference from the larger to the smaller reward is discussed in relation to current theory. The results of this experiment also provide evidence for the utility of tokens in scaling incentives for choice studies.     

Muscimol Induces Retrograde Amnesia for Changes in Reward Magnitude

These experiments examined the effect of the GABA_A, agonist, muscimol (MUS), on memory for changes in reward magnitude. In Experiment 1 rats were trained to run a straight alley for either a large or small food reward. After reaching asymptotic performance rats in the high reward group were shifted to the small food reward. Half the animals received 1.0 or 3.0 mg/kg (ip) of MUS or the equivalent volume of saline immediately after training. Shifted training continued for 3 more days and no further injections were given. Shifted saline animals displayed an increase in response latencies compared to unshifted controls with a sharp peak on the day after the shift. Shifted MUS receiving 1.0 mg/kg performed comparably to shifted saline animals. In contrast, shifted MUS animals receiving 3.0 mg/kg displayed performance comparable to shifted saline animals on the day of the shift but displayed a sharp increase in response latencies on the second day after the shift. These findings indicate that post-training systemic MUS injections delay the peak increase in response latencies and suggest that MUS induces retrograde amnesia for reward reduction. Experiment 2 examined the effect of MUS on the memory of a reward increase. Rats were first trained as in Experiment 1 and rats under the high reward condition were then shifted to the small reward. On the next training session, the large food reward was reinstated. Immediately after the session all animals were injected with saline or 3.0 mg/kg of MUS. The large food reward was continued for the remainder of training and no further injections were given. On the following session, the performance of the shifted saline animals was comparable to that of the unshifted controls while shifted MUS animals displayed significantly higher response latencies. The findings that MUS prevented the reduction in response latencies seen in saline-injected animals suggest that MUS also induces retrograde amnesia for reward increases.     

Interactions between deliberation and delay-discounting in rats

When faced with decisions, rats sometimes pause and look back and forth between possible alternatives, a phenomenon termed vicarious trial and error (VTE). When it was first observed in the 1930s, VTE was theorized to be a mechanism for exploration. Later theories suggested that VTE aided the resolution of sensory or neuroeconomic conflict. In contrast, recent neurophysiological data suggest that VTE reflects a dynamic search and evaluation process. These theories make unique predictions about the timing of VTE on behavioral tasks. We tested these theories of VTE on a T-maze with return rails, where rats were given a choice between a smaller reward available after one delay or a larger reward available after an adjustable delay. Rats showed three clear phases of behavior on this task: investigation, characterized by discovery of task parameters; titration, characterized by iterative adjustment of the delay to a preferred interval; and exploitation, characterized by alternation to hold the delay at the preferred interval. We found that VTE events occurred during adjustment laps more often than during alternation laps. Results were incompatible with theories of VTE as an exploratory behavior, as reflecting sensory conflict, or as a simple neuroeconomic valuation process. Instead, our results were most consistent with VTE as reflecting a search process during deliberative decision making. This pattern of VTE that we observed is reminiscent of current navigational theories proposing a transition from a deliberative to a habitual decision-making mechanism.     

Proactive interference and spontaneous alternation in rats

Two pairs of trials were given to naive rats in a T-maze. The first trial of a pair was forced to one arm, the second was free, and the delay between trials was 25 min. or 10 hr. Rats left in the maze for 15 sec. following the forced choice showed increased alternation on the second pair of trials at the 25-min. delay as compared with the 10-hr. delay. This was interpreted as due to a decline in alternation with delay on this pair of trials, together with an overall increase in alternation between the first and second pairs, and is consistent with the proactive interference theory of forgetting. Rats left in for 2 min. showed a decline in alternation with delay on the first pair of trials, but not on the second; this is inconsistent with the proactive interference theory.     

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.     

Dopamine D1 receptors in the anterior cingulate cortex regulate effort-based decision making

The anterior cingulate cortex (ACC) has been implicated in encoding whether or not an action is worth performing in view of the expected benefit and the cost of performing the action. Dopamine input to the ACC may be critical for this form of effort-based decision making; however, the role of distinct ACC dopamine receptors is yet unknown. Therefore, we examined in rats the effects of an intra-ACC D1 and D2 receptor blockade on effort-based decision making tested in a T-maze cost-benefit task. In this task, subjects could either choose to climb a barrier to obtain a high reward in one arm or a low reward in the other arm without a barrier. Unlike vehicle-treated rats, rats with intra-ACC infusion of the D1 receptor antagonist SCH23390 exhibited a reduced preference for the high-cost- high-reward response option when having the choice to obtain a low reward with little effort. In contrast, in rats with intra-ACC infusion of the D2 receptor antagonist eticlopride, the preference for the high-cost-high-reward response option was not altered relative to vehicle-treated rats. These data provide the first evidence that D1 receptors in the ACC regulate effort-based decision making.     

Infantile handling and the facilitation of discrimination and reversal learning

One group of rats was removed from their home cage and received daily handling from Days 3-21, while the control group of litter mates remained in the cage and did not receive any treatment. On Day 22 all rats were weaned and they were housed in individual cages until they were 60 days old. After two pretraining days, subjects were given daily blocks of one free and three forced trials in the T-maze and were rewarded with food after making the correct response. Following 20 days of training and testing on black-white discrimination, subjects were given 10 days of reversal training with four daily trials. Results indicate that the handled animals showed faster running and a greater number of correct choices than the control rats during both the acquisition and reversal learning phases of the experiment.