前扣带回与眶额皮层参与风险决策的不同过程

发布时间：2018-01-26 18:06

本文关键词： 风险决策概率折扣任务前扣带回眶额皮层　出处：《首都师范大学》2014年硕士论文　论文类型：学位论文

【摘要】：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。关于风险决策的神经机制一直是研究者关注的热点问题。概率折扣任务是风险决策研究的经典范式之一,旨在考察奖赏出现概率的变化对被试决策行为的影响。本研究运用多通道神经元放电同步记录技术,观察和记录大鼠在完成概率折扣任务过程中,前扣带回(anterior cingutate cortex, ACC)和眶额皮层(orbital frontal cortex, OFC)的神经元放电活动,分析ACC和OFC神经元放电变化与大鼠风险决策行为之间的相互关系,从而在细胞水平上探讨ACC与OFC在风险决策过程中的具体作用及其异同,本研究结果发现：(1)大鼠习得概率折扣任务后,能相应地调整选择行为以获得更多的奖赏；(2)在ACC与OFC中均记录到多种类型神经元,在风险决策的预期阶段,ACC中记录到预期兴奋和预期抑制两种神经元,预期兴奋神经元在预期阶段对冒险选择与保守选择的平均放电频率没有显著差异；而在大额奖赏的不同概率之间有显著差异。OFC中也记录到预期兴奋与抑制神经元,但这两种神经元的平均放电频率在是否冒险与不同奖赏概率之间均无显著差异。此外,ACC与OFC中还记录到动作+奖赏神经元和奖赏神经元。这些神经元分别参与风险决策过程中预期、动作执行和奖赏等重要阶段。(3)ACC中存在不同类型的神经元分别对奖赏数量,选择和动作是否冒险信息进行特异性编码,且能对100%、50%、25%、12.5%四种概率进行分辨并做出相应的放电频率反应；而OFC神经元则只对动作是否冒险以及奖赏数量进行特异性编码,对奖赏概率信息不敏感。本研究结果提示：ACC参与风险决策的预期与执行,ACC存在预期奖赏风险和预期动作价值的神经元,而在行为学稳定后,OFC不能预期风险程度。
[Abstract]:Risk decisions are determined by the results of different options. The neural mechanism of risk decision is always a hot issue that researchers pay attention to. Probability discount task is one of the classical paradigms of risk decision research. The purpose of this study was to investigate the effect of the change of probability of reward on the decision making behavior of the subjects. In this study, we used the multi-channel neuronal discharges synchronous recording technique to observe and record the rats in the process of completing the probabilistic discounted tasks. Anterior cingutate cortexes (ACCs) and orbital frontal cortex in anterior cingulate gyrus. To analyze the relationship between the changes of ACC and OFC neurons and the risk decision-making behavior of rats. In order to explore the specific role of ACC and OFC in the process of risk decision-making at the cellular level and their similarities and differences, the present study found that: 1) after learning probability discount task in rats. Can adjust the choice behavior accordingly to obtain more reward; Two types of neurons were recorded in both ACC and OFC, and two kinds of neurons, expected excitation and expected inhibition, were recorded in the expected stage of risk decision. There was no significant difference in the average discharge frequency between risk-taking and conservative selection in expected excitation neurons. There were significant differences in the probability of large reward. The expected excitation and inhibition neurons were also recorded in OFC. However, there was no significant difference in the average discharge frequency between the risk-taking and the different reward probability of these two kinds of neurons. Action reward neurons and reward neurons were also recorded in ACC and OFC. There are different types of neurons in the ACC, such as action execution and reward, which specifically encode the number of rewards, selection and whether the action is risky, and can encode 100% or 50% of the information. 25% 12.5% of the four probabilities were identified and the corresponding discharge frequency response was made. However, the OFC neurons only encode the risk of action and the number of rewards specifically, and are not sensitive to the information of reward probability. The present study suggests that OFC is involved in the expectation and execution of risk decision-making. There are neurons with expected reward risk and expected action value in ACC, while ACC can not predict the degree of risk after behavioral stability.
【学位授予单位】：首都师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：B848

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