Temporal Strategies in Visual Cortex

描述（由申请人提供）：行为依赖于对感官信息的可靠解释以及将该信息与行动的灵活关联。因此，它既依赖于感觉神经元对信息的准确编码，又依赖于根据任务约束对这些感觉信号进行适当的解码。在涉及感官环境快速变化的情况下，这些过程的速度可能是至关重要的：无法对迫在眉睫的威胁做出快速反应可能是致命的。在之前的拨款申请中获得的证据表明，单个神经元在几十毫秒内的活动可以准确地编码运动信息。当动物从事自然注视任务时，同样的短暂活动也强烈地预测了行为选择，因此可能在快速决策中发挥关键作用。提出的实验将探索这种精确度是如何在神经群中分布的，以及它是如何被训练或任务需求改变的。动物将在需要快速分析运动信息的任务中接受训练。同时记录的神经元活动和行为将进行分析，以推断感官信号的精度和可靠性及其对行为选择的影响。在第一个特定的目标，可靠的感觉信息的分布在皮质人口将被调查。在第一个实验中，附近的神经元将同时被运动刺激激活，以检查活动相关性如何改善或降低感觉信息及其与行为结果的关联。在第二个实验中，精确度和可靠性的刺激依赖性将被用来推断这些因素如何在广泛的激活神经元群体中变化。在第二个具体目标中，将在快速运动检测熟练程度的习得过程中对单个神经元进行记录，以研究这种精确度的习得程度。在第三个特定目标中，刺激和概率操作将用于揭示负责这种精确神经元活动的特定任务参数。因为所有这些任务都极具挑战性，它们将有助于揭示决策的准确性和速度的潜在限制。通过同时解决大脑内感觉编码和解码的可靠性和准确性，这些研究也可以为开发有效的假肢神经接口提供有价值的信息。

DESCRIPTION (provided by applicant): Behavior relies on the reliable interpretation of sensory information and the flexible association of that information with actions. It therefore depends on the both the accurate encoding of information by sensory neurons and the appropriate decoding of these sensory signals according to task constraints. In circumstances involving rapid changes in the sensory environment, the speed of these processes can be of paramount importance: an inability to quickly respond to a looming threat can be fatal. Evidence acquired in the previous grant submission demonstrates that the activity of single neurons over tens of milliseconds can accurately and precisely encode motion information. The same brief periods of activity were also strongly predictive of behavioral choice when animals were engaged in a natural foveation task, and therefore potentially play a pivotal role in rapid decision making. The proposed experiments will explore how such precision is distributed among neural populations and how it is altered by training or task demands. Animals will be trained in tasks requiring the rapid analysis of motion information. Simultaneous recording of neuronal activity and behavior will be analyzed to infer the precision and reliability of sensory signals and their influence on behavioral choice. In the first specific aim, the distribution of reliable sensory information over a cortical population will be investigated. In the first experiment, nearby neurons will be simultaneously activated by a motion stimulus in order to examine how activity correlations might improve or degrade sensory information and its association with behavioral outcome. In the second experiment, the stimulus dependence of precision and reliability will be used to infer how these factors vary across a broad population of activated neurons. In the second specific aim, recordings of individual neurons will be made during the acquisition of proficiency in rapid motion detection to study the extent to which this precision is learned. In the third specific aim, stimulus and probability manipulations will be used to reveal the specific task parameters responsible for such precise neuronal activity. Because all of these tasks are highly challenging, they will help reveal the underlying constraints on the accuracy and speed of decision making. By simultaneously addressing the reliability and precision of sensory encoding and decoding within the brain, these studies could also provide valuable information for the development of effective neural interfaces for prosthetics. PUBLIC HEALTH RELEVANCE: Decisions based on small epochs of perceptual information are often of life-or-death importance not only in nature but every time we cross a busy intersection or navigate a busy highway. However, no existing model is able to explain how our brains are able to rapidly and reliably process brief amounts of information and subsequently plan and execute appropriate actions on the basis on that information. This goal of this proposal is to reveal the physiological basis of such capabilities by investigating how neural activity in a specific brain area is able to precisely represent visual information and influence behaviors during the course of rapid decision making.