Neural mechanisms of long-term planning

描述（由申请人提供）：为了做出适应性决策，动物需要复杂的机制来跟踪结果的可取性、大小和概率。此外，动物必须在多个时间尺度上整合结果信息，并且必须具有不仅面向即时奖励而且面向延迟奖励的能力。对人类来说，几乎每一个决定都需要某种形式的提前计划，时间范围可以从相对较短的（去商店买冰淇淋）到非常长的（现在投资，以便在几十年后退休）。规划能力对正常行为至关重要，这一能力的受损可能会产生毁灭性的后果。两种主要的精神疾病-注意力缺陷障碍和成瘾-与计划缺陷和额叶和顶叶皮质区的功能障碍有关。然而，尽管长期规划的重要性，潜在的神经机制知之甚少。在这里，我们解决这个问题，使用顺序决策任务结合单神经元记录在猴子外侧顶内区（LIP）。这项任务要求猴子在两种备选策略中做出选择--一种是面向即时奖励的次优策略，另一种是面向最终（延迟）奖励的最优策略。虽然以前的研究集中在顺序和时序机制在连续的行动，在这里，我们专注于潜在的决策-行动评估-计算。大脑是如何根据一个只有在多个感官和运动事件介入后才能到达的未来（预期）奖励来给一个行为赋值的？大脑如何区分那些对获得延迟奖励至关重要的行为和那些不重要的行为？最后，大脑是如何解决跨期冲突的，为了保持对最终目标的关注而放弃即时奖励的？虽然大多数先前的研究都集中在额叶皮层，但在这里，我们记录了顶叶，连同额叶区域，可能对提前计划至关重要。因此，拟议的实验扩展了我们的知识，长期规划所需的决策机制，在更广泛的皮层网络。这些研究是必要的长期规划和精神障碍期间的故障的机械理解。1 公共卫生相关性：长期规划能力对于正常决策至关重要。计划障碍被认为是精神疾病的病因之一，包括注意力缺陷障碍和成瘾。虽然已经在人类受试者中进行了长期规划的研究，但基本的神经元机制仍然是未知的。本实验探讨了大脑在顺序决策任务中基于延迟而不是立即奖励分配行动价值的机制。目标是提供一个详细的了解规划机制在正常行为和精神疾病。1

DESCRIPTION (provided by applicant): To make adaptive decisions, animals require sophisticated mechanisms for tracking the desirability, magnitude and probability of an outcome. In addition, animals must integrate outcome information over multiple time scales, and must have the capacity to orient not only toward immediate but also toward delayed rewards. For humans, nearly every decision requires some form of advance planning, on time scales that can range from relatively short (going to the store in order to get an ice cream) to the exceptionally long (investing money now in order to retire in several decades). The capacity for planning is critical for normal behavior, and impairments in this faculty can have devastating consequences. Two major psychiatric disorders - attention deficit disorder and addiction - have been associated with planning deficits and with dysfunction in frontal and parietal cortical areas. However, despite the importance of long-term planning, the underlying neural mechanisms are poorly understood. Here we address this question using a sequential decision making task in conjunction with single- neuron recording in monkey lateral intra-parietal area (LIP). The task requires monkeys to choose between two alternative strategies - a suboptimal strategy oriented toward an immediate reward, and an optimal strategy oriented toward a final (delayed) reward. While prior studies have focused on ordering and timing mechanisms during sequential actions, here we focus on the underlying decisional - action evaluation - computations. How does the brain assign value to an action, based on a future (projected) reward that only arrives after multiple intervening sensory and motor events? How does the brain distinguish between actions that are and those that are not critical for obtaining a delayed reward? And finally, how does the brain resolve inter-temporal conflict, foregoing an immediate reward in order to remain focused on the final goal? While most prior studies have focused on the frontal cortex, here we record from the parietal lobe which, together with frontal areas, is likely to be critical for advance planning. Thus the proposed experiments extend our knowledge of the decision mechanisms required for long-term planning in a broader cortical network. These studies are necessary for a mechanistic understanding of long-term planning and its breakdown during mental disorders. 1 PUBLIC HEALTH RELEVANCE: The capacity for long-term planning is critical for normal decision making. Impairments in planning are thought to be part of the etiology of psychiatric disorders, including attention deficit disorders and addiction. While studies of long-term planning have been carried out in human subjects, the underlying neuronal mechanisms remain largely unknown. The present experiment probes the mechanisms by which the brain assigns action value based on delayed, rather than immediate rewards during a sequential decision making task. The goal is to provide a detailed understanding of planning mechanisms during normal behavior and mental illness. 1