CRCNS:Investigating perceptual processing speed and its impact on choice behavior

CRCNS：调查感知处理速度及其对选择行为的影响

• 批准号: 8496748
• 负责人: Emilio Salinas
• 金额: $ 28.7万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-30 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8496748
• 关键词: Acceleration; Affect; Attention; Behavior; Brain; Choice Behavior; Cognitive; Color; Commit; Computer Simulation; Decision Making; Dependency; Diagnostic; Education; Educational process of instructing; Equipment; Future; Judgment; Knowledge; Laboratories; Life; Light; Measurement; Measures; Mental disorders; Minor; Modeling; Monkeys; Motivation; Motor; Neurobiology; Neurons; Neurosciences; Performance; Postdoctoral Fellow; Preparation; Principal Investigator; Process; Psychophysics; Reaction Time; Readiness; Reporting; Research; Research Infrastructure; Resolution; Rewards; Role; Sensory; Signal Transduction; Societies; Speed; Stimulus; Task Performances; Testing; Time; Training; Variant; base; decision-making capacity; design; frontal eye fields; graduate student; human subject; microstimulation; neural circuit; neuromechanism; neurophysiology; novel; oculomotor; processing speed; programs; relating to nervous system; research study; response; skills; tool; trafficking; undergraduate student

DESCRIPTION (provided by applicant): The neurobiology of choice behavior has been intensely studied with laboratory tasks in which a subject makes a perceptual judgement and indicates the result with a motor action. Combined psychophysical and neurophysiological experiments have thus characterized perceptual decision-making capacity as a function of signal quality, strength, and subjective value, and have revealed many of the underlying neural circuits and their specific roles. However, the fundamental question of timing has been much harder to tackle: how long does it take to make a perceptual judgment, versus executing a motor action to report that judgment? At what point in time is a subject committed to a particular choice, and what neural mechanisms determine that? These issues are relevant to many real-life situations that require quick choices; for instance, when a driver sees a traffic light and must rapidly decide whether to step on the brake or the accelerator, depending on the light's color. But making accurate timing measurements is complicated because they are affected by numerous sensory and motor factors, such as readiness, motivation, task difficulty and speed-accuracy trade-offs. Consequently, current knowledge about the temporal dynamics of perceptual decision-making is rather crude. The PIs in this project recently developed a task that eliminates these confounds and produces a new psychophysical measure, the tachometric curve, which isolates a subject's perceptual processing capacity and quantifies it with unprecedented temporal resolution. They have also constructed a computational model that reproduces the subjects' behavior with great detail. The new paradigm and the model will be used jointly to investigate the timing of perceptual judgments and its neural basis. Specific model predictions will be tested via single-neuron recording and microstimulation within the Frontal Eye Field (FEF) of monkeys trained to perform the task under a variety of conditions. There are three specific aims. Aim 1: To test the hypothesis that changes in perceptual processing speed are manifested as changes in the slope of the tachometric curve (psychophysically) and in the acceleration of the oculomotor activity associated with a saccadic choice (neurally). According to the model, the tachometric curve and the oculomotor activity associated with saccadic choices should depend in specific ways on perceptual difficulty. To measure this dependency, subjects will perform 3 versions of the same choice task that will vary in perceptual difficulty according to different stimulus features to be discriminated. Aim 2: To test the hypothesis that when perceptual processing speed remains constant, both the slope of the tachometric curve and the acceleration of the oculomotor activity will stay constant as well, even if other measures of psychophysical performance do change. These experiments are thus complementary to those of Aim 1. Subjects will perform 4 variants of the choice task in which perceptual difficulty will be fixed but the likelihoods and rewards associated with the two possible motor responses will vary. The subject's performance level, reaction times and proportions of choices are expected to change drastically across the 4 conditions, but the measured correlates of perceptual processing speed should not. Aim 3: To test the hypothesis that an overall increase in the level of activation in FEF alters the timing and accuracy of a subject's choices, but not the observed perceptual processing speed. Subthreshold microstimulation current will be injected into the FEF at different points in time during task performance. The question is whether the evoked activity is interpreted as a purely motor signal or if it has a direct impact on the subject's perceptual processing capacity. Intellectual merit: The proposed experiments track how a subject's perceptual performance unfolds in time, and open up an entirely new avenue for investigating how choices are made. It will be possible (1) to determine the specific contributions of various cognitive factors such as attention, motivation, motor preparation, and perceptual processing speed to a subject's measured psychophysical performance, (2) to investigate how neuronal activity is related to each of these factors during a choice task, and (3) to reveal how the time course of this neuronal activity correlates with the time course of a subject's choice accuracy. Broader impacts: (1) Teaching. The results of this study will be incorporated into courses taught by the PIs. (2) Education. Undergraduate students with a minor in neuroscience will be hosted for research academic credit in the PIs' laboratories. A graduate student and a postdoctoral fellow will develop combined electrophysiological and computational skills. (3) Scientific understanding. The results are expected to be widely discussed and disseminated. (4) Enhancement of infrastructure for research. Cutting-edge equipment will be acquired for use in this and future projects. (5) Benefits to society. The novel task design has the potential to be adapted to human subjects and become a powerful diagnostic tool for elucidating how specific neural circuits or brain 'modules' are compromised by a given mental disorder.

描述（由申请人提供）：选择行为的神经生物学已经通过实验室任务进行了深入研究，其中受试者做出感性判断并通过运动动作表明结果。因此，心理物理学和神经生理学的结合实验将感知决策能力描述为信号质量、强度和主观价值的函数，并揭示了许多潜在的神经回路及其具体作用。然而，时间的基本问题更难解决：做出感知判断和执行运动动作报告判断需要多长时间？受试者在什么时间点会做出特定的选择，什么神经机制决定了这一点？这些问题与许多需要快速做出选择的现实情况有关；例如，当司机看到交通灯时，必须根据灯的颜色迅速决定是踩刹车还是踩油门。但是，精确的计时测量是复杂的，因为它们受到许多感觉和运动因素的影响，比如准备程度、动机、任务难度和速度-准确性之间的权衡。因此，目前关于感知决策的时间动态的知识相当粗糙。该项目的pi最近开发了一项任务，消除了这些混淆，并产生了一种新的心理物理测量，即速度曲线，它分离了受试者的感知处理能力，并以前所未有的时间分辨率对其进行量化。他们还构建了一个计算模型，可以非常详细地再现受试者的行为。新范式和模型将共同用于研究知觉判断的时间及其神经基础。具体的模型预测将通过单神经元记录和额眼场（FEF）内的微刺激来测试，这些猴子被训练在各种条件下执行任务。有三个具体目标。目的1：检验知觉加工速度的变化表现为速度曲线斜率的变化（心理物理上）和与跳眼选择相关的动眼肌活动的加速（神经上）。根据该模型，与跳眼选择相关的速测曲线和动眼肌活动应该以特定的方式依赖于感知困难。为了测量这种依赖性，受试者将执行3个版本的相同选择任务，这些选择任务根据不同的刺激特征在感知难度上有所不同。目的2：测试假设，当知觉处理速度保持不变时，速测曲线的斜率和动眼肌活动的加速度也将保持不变，即使其他心理物理表现的测量值确实发生了变化。因此，这些实验与Aim 1的实验是互补的。受试者将执行四种选择任务，其中感知困难是固定的，但两种可能的运动反应的可能性和奖励是不同的。受试者的表现水平、反应时间和选择的比例在4种情况下预计会发生巨大变化，但感知处理速度的测量相关性不会发生变化。目的3：测试FEF激活水平的整体增加会改变受试者选择的时间和准确性，但不会改变观察到的感知处理速度的假设。阈下微刺激电流将在任务执行过程中的不同时间点注入FEF。问题是，被唤起的活动是否被解释为纯粹的运动信号，或者它是否对受试者的感知处理能力有直接影响。智力价值：提出的实验跟踪受试者的感知表现如何随时间展开，并为研究如何做出选择开辟了一条全新的途径。这将有可能(1)确定各种认知因素（如注意力、动机、运动准备和知觉处理速度）对被试心理物理表现的具体贡献，(2)研究在选择任务中神经元活动如何与这些因素相关，(3)揭示这种神经元活动的时间过程如何与被试选择准确性的时间过程相关。更广泛的影响：(1)教学。这项研究的结果将被纳入pi教授的课程中。(2)教育。辅修神经科学专业的本科生将在pi的实验室获得研究学分。一名研究生和一名博士后将培养电生理和计算技能。(3)科学认识。预期调查结果将得到广泛讨论和传播。(4)加强科研基础设施建设。将获得尖端设备用于这个和未来的项目。(5)社会效益。这种新颖的任务设计有可能适用于人类受试者，并成为一种强大的诊断工具，用于阐明特定的神经回路或大脑“模块”是如何受到特定精神障碍的损害的。