The Neural Basis of Decision-Making: Cortical & Subcortical Mechanisms

你喜欢哪一个，12个月赚20美元还是13个月赚22美元？大多数人都会等待 365天后再问自己同样的问题：你更喜欢哪一个，20美元 今天还是一个月22美元？现在大多数人会选择眼前的收益20美元； 偏好。坐在诊所里，大多数吸毒者表示倾向于在当天晚些时候避免吸毒。 几个小时后，面对一种立即可用的药物，他们的偏好发生了逆转。这些观察揭示了 人类通过比较奖励的主观价值来做出选择，而这些价值并不取决于 只是关于奖励有多大，而是什么时候会收到奖励。满足感推迟的时间越长； 不那么令人满意的奖励似乎出现了。经验数据表明，这种可取性的下降发生在 在短暂的延迟中突然出现，随着延迟的增加而逐渐增加。也许同样有趣的是 观察发现，基本上所有脊椎动物似乎都表现出类似的模式。那么，神经是什么？ 为延迟奖励设定主观价值的机制？ 有关决策的神经生物学研究在很大程度上回避了这个问题。在此应用程序中，我们 建议将现有的神经生物学决策研究扩展到时间选择领域。我们 建议采用行为、生理和功能磁学相结合的方法进行这项研究 磁共振成像技术，并测试试图解释时间选择的两个假说：a 经济理论的标准生理模型和占主导地位的两系统模型。具体来说，我们 建议对这两个模型都能解释顶后活动的假设进行检验 大脑皮质和腹侧纹状体在一系列条件下。 延误对决策的病理性影响在疾病中普遍存在。延误扭曲了 注意力缺陷障碍儿童、病态赌徒、吸毒者、吸烟者、 酗酒者、可卡因和海洛因成瘾者。尽管对延误的异常敏感控制着 所有这些患者群体的行为，几乎对这种疾病的机制一无所知。我们 提出了一系列旨在阐明其病理基础的基本机制的实验 在时间上做出不恰当选择的决策。

Which would you prefer, a gain of $20 in 12 months or of $22 in 13 months? Most people would wait the extra month to gain the extra $2. Ask yourself the same question 365 days later: which would you prefer, $20 today or $22 in a month? Now most people would select the immediate gain of $20; a reversal in preferences. Sitting in a clinic, most drug users state a preference for avoiding drug use later in the day. Hours later, confronting an immediately available drug, their preferences reverse. These observations reveal that humans make choices by comparing the subjective values of rewards and that these values depend not just on how large a reward is but when that reward will be received. The longer gratification is delayed; the less desirable a reward appears. Empirical data suggeststhat this decrease in desirability occurs most abruptly at short delays and more gradually as delays increase. Perhaps just as interesting is the observation that essentially all vertebrates appear to show a similar pattern. What then, is the neural mechanism that sets a subjective value on delayed rewards? Neurobiological studies of decision-making have largely avoided this issue. In this application we propose to extend existing neurobiological studies of decision-making into the domain of choice-in-time. We propose to undertake this study with a combination of behavioral, physiological and functional magnetic resonance imaging techniques and to test two hypotheses that seek seek to explain choice-in-time: a standard physiological model and the dominant two-system model of economic theory. Specifically, we propose to test the hypothesis that either of these models can account for the activity of the posterior parietal cortex and the ventral striatum under a range of conditions. Pathological influences of delays on decision making are pervasive in disease. Delays distort the decisions made by children with attention-deficit disorder, pathological gamblers, drug abusers, smokers, alcoholics, cocaine and heroin addicts. Despite the fact that an abnormal sensitivity to delays controls the behavior of all of these patient groups, almost nothing is known about the mechanism of this disorder. We propose a series of experiments aimed at elucidating the basic mechanism that underlies the pathological decision making that marks inappropriate choice-in-time.