最近，杜克大學(xué)醫(yī)學(xué)中心的研究人員利用腦部掃描,，能夠預(yù)測(cè)出猴子利用已知資源對(duì)未知事物所作的選擇,。該研究發(fā)表在本周的Current Biology雜志上。
“人類不是唯一的不滿足現(xiàn)狀的動(dòng)物,，可人們?cè)谙Ｍ玫礁玫耐瑫r(shí)也不愿意放棄已有事物。而這項(xiàng)研究有助于解釋在做類似的取舍時(shí),，大腦權(quán)衡成本和利益之間關(guān)系的過程,。”該報(bào)告的主要作者John Pearson說。
研究人員給猴子提供四杯可選擇的200ml的果汁,，當(dāng)猴子做選擇的同時(shí),，研究人員觀察猴子大腦后扣帶腦皮質(zhì)(posterior cingulate cortex)神經(jīng)元細(xì)胞的發(fā)出的信號(hào)。一般情況下,，當(dāng)猴子作選擇時(shí)神經(jīng)元發(fā)出的信號(hào)最強(qiáng),。然后，研究人員使4杯果汁緩慢發(fā)生變化——變多或變少，此時(shí),，猴子可以根據(jù)其自身的價(jià)值觀和知識(shí)信息,，選擇更換新目標(biāo)或保持原來的選擇，使獲得的果汁分量最多,。
通過研究單個(gè)神經(jīng)元,，研究人員能夠預(yù)測(cè)出猴子所采用的選擇策略。
據(jù)該研究的作者之一Michael Platt介紹,，從人類健康角度來看,，該研究中獲得的數(shù)據(jù)對(duì)研究老年癡呆癥或強(qiáng)迫癥等均有一定啟發(fā)性，因?yàn)楹罂蹘X皮質(zhì)是大腦代謝最活躍部分之一,，老年癡呆癥也是由于這部分受損引起的,。關(guān)于大腦這部分的功能還需要進(jìn)一步的試驗(yàn)研究。（生物谷Bioon.com）
生物谷推薦原始出處：
Current Biology, 03 September 2009 doi:10.1016/j.cub.2009.07.048
Neurons in Posterior Cingulate Cortex Signal Exploratory Decisions in a Dynamic Multioption Choice Task
John M. Pearson1,,,Benjamin Y. Hayden1,Sridhar Raghavachari1andMichael L. Platt1,2
1 Department of Neurobiology, Duke University School of Medicine and Center for Neuroeconomic Studies, Duke University, Durham, NC 27710, USA
2 Center for Cognitive Neuroscience and Department of Evolutionary Anthropology, Duke University, Durham, NC 27710, USA
In dynamic environments, adaptive behavior requires striking a balance between harvesting currently available rewards (exploitation) and gathering information about alternative options (exploration) [1,2,3,4]. Such strategic decisions should incorporate not only recent reward history, but also opportunity costs and environmental statistics. Previous neuroimaging [5,6,7,8] and neurophysiological [9,10,11,12,13] studies have implicated orbitofrontal cortex, anterior cingulate cortex, and ventral striatum in distinguishing between bouts of exploration and exploitation. Nonetheless, the neuronal mechanisms that underlie strategy selection remain poorly understood. We hypothesized that posterior cingulate cortex (CGp), an area linking reward processing, attention [14], memory [15,16], and motor control systems [17], mediates the integration of variables such as reward [18], uncertainty [19], and target location [20] that underlie this dynamic balance. Here we show that CGp neurons distinguish between exploratory and exploitative decisions made by monkeys in a dynamic foraging task. Moreover, firing rates of these neurons predict in graded fashion the strategy most likely to be selected on upcoming trials. This encoding is distinct from switching between targets and is independent of the absolute magnitudes of rewards. These observations implicate CGp in the integration of individual outcomes across decision making and the modification of strategy in dynamic environments.
