發(fā)布時(shí)間：2018-01-26 18:06

  本文關(guān)鍵詞： 風(fēng)險(xiǎn)決策 概率折扣任務(wù) 前扣帶回 眶額皮層　出處：《首都師范大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：風(fēng)險(xiǎn)決策是在不同選項(xiàng)的結(jié)果確定,并且結(jié)果出現(xiàn)的概率已知情況下的決策。關(guān)于風(fēng)險(xiǎn)決策的神經(jīng)機(jī)制一直是研究者關(guān)注的熱點(diǎn)問題。概率折扣任務(wù)是風(fēng)險(xiǎn)決策研究的經(jīng)典范式之一,旨在考察獎(jiǎng)賞出現(xiàn)概率的變化對被試決策行為的影響。本研究運(yùn)用多通道神經(jīng)元放電同步記錄技術(shù),觀察和記錄大鼠在完成概率折扣任務(wù)過程中,前扣帶回(anterior cingutate cortex, ACC)和眶額皮層(orbital frontal cortex, OFC)的神經(jīng)元放電活動(dòng),分析ACC和OFC神經(jīng)元放電變化與大鼠風(fēng)險(xiǎn)決策行為之間的相互關(guān)系,從而在細(xì)胞水平上探討ACC與OFC在風(fēng)險(xiǎn)決策過程中的具體作用及其異同,本研究結(jié)果發(fā)現(xiàn)：(1)大鼠習(xí)得概率折扣任務(wù)后,能相應(yīng)地調(diào)整選擇行為以獲得更多的獎(jiǎng)賞；(2)在ACC與OFC中均記錄到多種類型神經(jīng)元,在風(fēng)險(xiǎn)決策的預(yù)期階段,ACC中記錄到預(yù)期興奮和預(yù)期抑制兩種神經(jīng)元,預(yù)期興奮神經(jīng)元在預(yù)期階段對冒險(xiǎn)選擇與保守選擇的平均放電頻率沒有顯著差異；而在大額獎(jiǎng)賞的不同概率之間有顯著差異。OFC中也記錄到預(yù)期興奮與抑制神經(jīng)元,但這兩種神經(jīng)元的平均放電頻率在是否冒險(xiǎn)與不同獎(jiǎng)賞概率之間均無顯著差異。此外,ACC與OFC中還記錄到動(dòng)作+獎(jiǎng)賞神經(jīng)元和獎(jiǎng)賞神經(jīng)元。這些神經(jīng)元分別參與風(fēng)險(xiǎn)決策過程中預(yù)期、動(dòng)作執(zhí)行和獎(jiǎng)賞等重要階段。(3)ACC中存在不同類型的神經(jīng)元分別對獎(jiǎng)賞數(shù)量,選擇和動(dòng)作是否冒險(xiǎn)信息進(jìn)行特異性編碼,且能對100%、50%、25%、12.5%四種概率進(jìn)行分辨并做出相應(yīng)的放電頻率反應(yīng)；而OFC神經(jīng)元?jiǎng)t只對動(dòng)作是否冒險(xiǎn)以及獎(jiǎng)賞數(shù)量進(jìn)行特異性編碼,對獎(jiǎng)賞概率信息不敏感。本研究結(jié)果提示：ACC參與風(fēng)險(xiǎn)決策的預(yù)期與執(zhí)行,ACC存在預(yù)期獎(jiǎng)賞風(fēng)險(xiǎn)和預(yù)期動(dòng)作價(jià)值的神經(jīng)元,而在行為學(xué)穩(wěn)定后,OFC不能預(yù)期風(fēng)險(xiǎn)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.
【學(xué)位授予單位】：首都師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：B848

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本文編號(hào)：1466248