Analyzing contextual adaptation in value-encoding neurons during economic choice.

 描述(由申请人提供)：拟议的研究将调查编码主观价值的神经元中语境适应的动态和局限性。经济决策方面的缺陷是一系列精神和神经疾病的特征。这些赤字的来源很难确定，很大程度上是因为人们对经济选择背后的神经机制仍知之甚少。有几条证据表明，眶前皮质(OFC)在经济选择中发挥着关键作用，特别是在主观价值的计算中。对猕猴的研究已经确定了不同的OFC神经元组，这些神经元编码关于经济选择过程中选项和结果的主观价值的信息。此外，这些神经元的反应似乎会根据选择的背景进行调整。具体地说，这些神经元似乎调整了它们的调谐，使它们的最大放电频率始终映射到动物最近看到的最大值。鉴于这些意见，仍有几个关键问题有待解决。首先，虽然最大值的变化会触发适应，但最小值的变化是否会产生任何影响尚不清楚。这个问题的答案可以解释已知的行为现象，如边际效用递减原理。其次，尚不清楚价值适应能以多快的速度发生。缓慢的适应速度可能会限制受试者在快速变化的环境中有效地做出决定的能力。第三，尚不清楚价值适应是否需要经历极端的价值观，或者是否可以由关于环境中价值观的抽象信息触发。如果适应可以由符号线索诱导，这将表明记忆和语义知识可以直接操纵主观价值的神经表征来影响经济选择。我将在拟议的实验中解决这些问题。我将从单个神经元记录猕猴在果汁选项中进行选择时的OFC，在整个过程中定期改变上下文。根据我获得的数据，我将确定神经反应是否会受到最小值变化的影响，测量编码数值的细胞中的适应速度，并测试上下文线索是否可以在动物暴露于极端值之前诱导适应。这个项目的结果将对大脑中价值表征的灵活性提供重要的见解。这些信息将填补我们对经济选择回路的理解中的重要空白，并最终可能指导开发更有效的治疗方案，损害患者群体的决策。

 DESCRIPTION (provided by applicant): The proposed research will investigate the dynamics and limitations of contextual adaptation in neurons that encode subjective value. Deficits in economic decision-making characterize a wide range of psychiatric and neurological disorders. The source of these deficits is difficult to determine, in great part because the neural mechanisms behind economic choice remain poorly understood. Several lines of evidence suggest that the orbitofrontal cortex (OFC) plays a key role in economic choice, and particularly in the computation of subjective value. Studies in macaques have identified distinct groups of OFC neurons that encode information about the subjective value of options and outcomes during economic choice. Furthermore, the responses of these neurons appear to adapt depending on the context of the choice. Specifically, these neurons appear to adjust their tuning so that their maximum firing rate always maps to the maximum value the animal has recently seen. In light of these observations, several key questions remain to be addressed. First, while changes in the maximum value trigger adaptation, it is unclear whether changes in the minimum have any effect. The answer to this question could explain known behavioral phenomenon, such as the principle of diminishing marginal utility. Second, it is unclear how quickly value-adaptatio can occur. A slow rate of adaptation could limit subjects' abilities to make decisions effectively n rapidly changing environments. Third, it is unclear whether value-adaptation requires experience of extreme values, or if it can be triggered by abstract information about the values in an environment. If adaptation can be induced by symbolic cues, it would suggest that memory and semantic knowledge can directly manipulate neural representations of subjective value to influence economic choice. I will address these questions in the proposed experiments. I will record from single neurons OFC of macaque monkeys as they choose between juice options, periodically changing the context throughout the session. With the data I obtain, I will determine whether neural responses are affected by changes in the minimum value, measure the rate of adaptation in value-encoding cells, and test whether contextual cues are can induce adaptation before an animal is exposed to extreme values. The results from this project will provide important insight about the flexibility of value representations in the brain. This information wil fill important gaps in our understanding of economic choice circuitry and may ultimately guide the development of more effective treatment options impaired decision-making in patient populations.