Top-down selection of task-relevant cues: neural mechanisms in the frontal and parietal lobes.

 描述（由申请人提供）：扫视是一种快速的眼球运动，通过这种运动，中央凹动物检查视觉场景。来自人类和猴子的证据表明，扫视的一个关键作用是收集视觉信息，以指导随后的行动。与这些行为观察相一致，整个猴子视觉系统的神经元选择性地对任务相关刺激相对于干扰物做出反应，并且这种增强被认为部分来自两个相互关联的区域，外侧顶内区（LIP）和额叶眼区（FEF）。然而，我们对这种选择是如何进行的知之甚少：FEF和LIP神经元识别相关项目的计算是什么？在这里，我们研究了一个双重控制的假设，这是由自然行为的计算建模和状态，自上而下的凝视控制是基于两个相互作用的因素：收益的奖励和收益的信息，扫视预计带来的。我们使用了一种新颖的两步任务，猴子在每次试验中进行两次眼跳-第一次眼跳是为了采样视觉信息，第二次眼跳是为了报告基于该信息的决定。我们操纵最终决策的奖励和信息需求（不确定性），并研究这如何影响第一个信息采样动作的目标选择。使用这种范式，我们获得了支持双重控制假说的初步证据，并表明：（1）LIP中的目标选择反应显示出强烈的调制奖励和不确定性（或等效的，预期的信息增益），和（2）可逆失活的这一领域损害目标选择的线索有效性（预期的信息增益），而不是简单的奖励协会。我们建议扩展这些研究结果，系统地探讨如何奖励和信息增益调节眼跳选择反应FEF和LIP（目标1），这两个因素如何调节反应相关的隐蔽选择（目标2），以及如何可逆失活的每个区域的影响奖励和基于信息的选择（目标3）。这些研究对于眼动学研究来说是非常重要和创新的，因为它们（1）提供了新的和急需的经验证据来支持自上而下的凝视控制的计算建模，（2）澄清了FEF和LIP之间的功能区别，到目前为止，它们似乎执行非常相似的功能，（3）澄清了眼动学决策如何依赖于除了主要奖励之外的信息增益，从而解决了长期存在的奖励和注意力之间的混淆，并将神经研究与自然凝视控制研究联系起来。这些研究在更广泛的范围内也具有重要意义和创新性，因为它们是第一个调查注意力与决策之间关系的研究，并探索基于信息价值的决策的神经基础。因此，这些研究预计将对我们对注意力和决策的理解产生重大影响，这两种核心认知功能在复杂行为和精神疾病中至关重要，包括注意力缺陷障碍，药物成瘾，焦虑和抑郁。1

 DESCRIPTION (provided by applicant): Saccades are rapid eye movements through which foveate animals examine visual scenes. Converging evidence from humans and monkeys show that a key role of saccades is to samplie visual information to guide subsequent actions. Consistent with these behavioral observations, neurons throughout the monkey visual system respond selectively for task-relevant stimuli relative to distractors, and this enhancement is thought to arise in part from two interconnected areas, the lateral intraparietal area (LIP) and th frontal eye field (FEF). However, we have little understanding about how this selection is made: what are the computations by which FEF and LIP neurons identify relevant items? Here we examine a dual-control hypothesis that is suggested by computational modeling of natural behavior and states that top-down gaze control is based on two interacting factors: the gains in reward and gains in information that a saccade is expected to bring. We use a novel two- step task where monkeys make two saccades on each trial - a first saccade to sample visual information and a second saccade to report a decision based on that information. We manipulate the reward and informational demands (uncertainty) of the final decision, and examine how this affects target selection for the first, information sampling action. Using this paradigm we obtained preliminary evidence that supports the dual control hypothesis and shows that (1) target selective responses in LIP show a strong modulation by both reward and uncertainty (or equivalently, expected information gains), and (2) reversible inactivation of this area impairs target selection based on cue validity (expected information gains) but not simple reward associations. We propose to extend these findings to systematically explore how reward and information gains modulate saccade selection responses in FEF and LIP (Aim 1), how the two factors modulate responses related to covert selection (Aim 2), and how reversible inactivation of each area impacts reward and information-based selection (Aim 3). These studies are highly significant and innovative for oculomotor research because they (1) provide new and much needed empirical evidence to support computational modeling of top-down gaze control, (2) clarify functional distinctions between FEF and LIP, which so far appear to perform very similar functions, (3) clarify how oculomotor decisions depend on information gains in addition to primary rewards, thereby resolving longstanding confounds between reward and attention and linking neural studies with studies of natural gaze control. The studies are also significant and innovative on a broader scope because they are among the first to investigate the relation between attention and decision making and to probe the neural basis of decisions based on the value of information. Thus, the studies are expected to have a strong impact on our understanding of attention and decision making, two core cognitive functions that are critical in complex behaviors and psychiatric diseases including attention deficit disorder, drug addiction, anxiety and depression. 1