最近，杜克大学医学中心的研究人员利用脑部扫描，能够预测出猴子利用已知资源对未知事物所作的选择。该研究发表在本周的Current Biology杂志上。
“人类不是唯一的不满足现状的动物，可人们在希望得到更好的同时也不愿意放弃已有事物。而这项研究有助于解释在做类似的取舍时，大脑权衡成本和利益之间关系的过程。”该报告的主要作者John Pearson说。
研究人员给猴子提供四杯可选择的200ml的果汁，当猴子做选择的同时，研究人员观察猴子大脑后扣带脑皮质(posterior cingulate cortex)神经元细胞的发出的信号。一般情况下，当猴子作选择时神经元发出的信号最强。然后，研究人员使4杯果汁缓慢发生变化——变多或变少，此时，猴子可以根据其自身的价值观和知识信息，选择更换新目标或保持原来的选择，使获得的果汁分量最多。
通过研究单个神经元，研究人员能够预测出猴子所采用的选择策略。
据该研究的作者之一Michael Platt介绍，从人类健康角度来看，该研究中获得的数据对研究老年痴呆症或强迫症等均有一定启发性，因为后扣带脑皮质是大脑代谢最活跃部分之一，老年痴呆症也是由于这部分受损引起的。关于大脑这部分的功能还需要进一步的试验研究。（生物谷Bioon.com）
生物谷推荐原始出处：
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.
