Anticipatory Hemodynamic Signals in Primary Visual Cortex

初级视觉皮层的预期血流动力学信号

• 批准号: 8069151
• 负责人: ANIRUDDHA DAS
• 金额: $ 38.64万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8069151
• 关键词: Affect; Animal Model; Animals; Arousal; Attention; Attention Deficit Disorder; Auditory; Behavior; Blood; Blood Volume; Brain; Clinical; Complex; Detection; Discrimination; Disease; Electrodes; Electrophysiology (science); Event; Functional Magnetic Resonance Imaging; Goals; Hand; Health; Hemoglobin; Human; Image; Imaging Techniques; Laboratories; Light; Link; Location; Macaca; Macaca mulatta; Measures; Medical; Modality; Monitor; Monkeys; Neurons; Pathway interactions; Performance; Physiological; Principal Investigator; Process; Public Health; Pump; Signal Transduction; Site; Specificity; Stimulus; Stress; Task Performances; Techniques; Testing; Tissues; Visual; Visual Cortex; Work; alertness; area striata; base; hemodynamics; insight; neuroimaging; neuromechanism; novel; optical imaging; programs; response; tool; visual process; visual processing

Description (provided by applicant): Our long-term goal is to understand the neural mechanisms of visual processing early in the cortical pathway. To this end we record from rhesus macaque visual cortex using a combination of intrinsic-signal optical imaging and electrophysiology while the animals are engaged in visual form processing tasks. The goal of the current project is two-fold. We propose to study a novel stimulus-independent anticipatory haemodynamic signal that we observed earlier in alert macaque V1 (primary visual cortex). Through this process we also propose to better understand the physiological basis of neuroimaging signals including fMRI. This project derives from our recent discovery that haemodynamic signals in alert monkey V1 have two distinct components. One component is predictable by visual input and associated V1 neuronal activity. The other component - of comparable strength - is a hitherto unknown haemodynamic signal marking task anticipation. It reflects an arterial pumping mechanism bringing fresh blood to cortex in anticipation of predicted visual events. Electrode recordings conducted simultaneously with the optical imaging showed that this novel haemodynamic signal is not driven by local V1 neuronal activity, in dramatic contrast to visually evoked responses obtained from the same recording sites. We hypothesize that the anticipatory stimulus-independent haemodynamic signal is a mechanism of predictive arousal. We propose to test this hypothesis by characterizing the anticipatory and visually evoked signals, and their interaction, and asking if the anticipatory signal can modulate visually evoked responses and behavior. Our finding of the novel haemodynamic signal also challenges current understandings of neuroimaging signals, notably functional magnetic resonance imaging (fMRI), the most commonly used tool for human neuroimaging. Through the course of this project we will investigate the links between neuroimaging signals and electrophysiology in the alert macaque in a variety of visual perceptual tasks. This will be an unparalleled opportunity to gain new insights into fMRI in an animal model that is the closest possible to the human. Our novel findings were obtained as a result of a new imaging technique developed in our laboratory, continuous dual-wavelength intrinsic-signal optical imaging, combined with electrode recordings, in alert behaving macaques. For the imaging, one wavelength is absorbed preferentially in oxygenated haemoglobin, thus monitoring blood oxygenation; the other wavelength, absorbed equally in oxygenated and deoxygenated haemoglobin, measures blood volume. The simultaneous electrode recordings give an electrophysiological measure of the underlying neuronal activity. The continuous recording allows us to distinguish between ongoing signals and stimulus-evoked responses. This technique will form the basis of the current project, giving a unique combination of tools to answer the questions at hand. PUBLIC HEALTH RELEVANCE This project has two significant implications for public health. We propose to characterize a novel mechanism of brain arousal, thus shedding new light on processes of attention or alertness and their disorders (attention deficit disorder etc.). Further, our work challenges the current understanding of functional magnetic resonance imaging (fMRI), the most commonly used means of studying the human brain in clinical or scientific settings, and will therefore have major implications for the correct interpretation of this critically important medical tool.

描述（由申请人提供）：我们的长期目标是了解皮质途径早期视觉处理的神经机制。为此，我们使用固有信号光学成像和电生理学的组合从恒河猕猴视觉皮层记录下来，而动物则参与视觉形式处理任务。当前项目的目标是两个方面。我们建议研究一种新型刺激依赖性的预期血流动力学信号，我们在Alert Macaque V1（主要视觉皮层）中观察到。通过此过程，我们还建议更好地了解包括功能磁共振成像在内的神经成像信号的生理基础。该项目源于我们最近的发现，即警报猴V1中的血液动力学信号具有两个不同的组成部分。一个成分是可以通过视觉输入和相关的V1神经元活性来预测的。另一个具有可比强度的成分是迄今未知的血液动力学信号标记任务预期。它反映了一种动脉抽水机制，可预测预测的视觉事件，将新鲜的血液带到皮层。与光学成像同时进行的电极记录表明，这种新型的血液动力学信号不是由局部V1神经元活性驱动的，与从同一记录位点获得的视觉诱发响应形成鲜明对比。我们假设预期的刺激非依赖性的血液动力学信号是一种预测性唤醒的机制。我们建议通过表征预期和视觉诱发的信号及其相互作用来检验这一假设，并询问预期信号是否可以调节视觉诱发的响应和行为。我们对新型血液动力学信号的发现也挑战了当前对神经影像学信号的理解，即功能性磁共振成像（fMRI），这是人类神经影像学的最常用工具。在该项目的过程中，我们将在各种视觉感知任务中调查神经成像信号与电生理学之间的联系。这将是一个无与伦比的机会，可以在最接近人类的动物模型中获得对fMRI的新见解。我们的新发现是由于在我们的实验室中开发的一种新成像技术，即连续的双波长固有信号光学成像，并结合了电极记录，并在警报上表现出猕猴。对于成像，一个波长在氧化血红蛋白中优先吸收，从而监测血液氧合。其他波长在氧化和脱氧的血红蛋白中同样吸收，可测量血液体积。同时电极记录给出了基本神经元活性的电生理测量。连续记录使我们能够区分正在进行的信号和刺激诱发的响应。该技术将构成当前项目的基础，从而提供独特的工具组合来回答手头上的问题。公共卫生相关性这个项目对公共卫生有两个重要的影响。我们建议表征一种新颖的脑唤醒机制，从而为注意力或机敏性及其疾病（注意缺陷障碍等）提供了新的启示。此外，我们的工作挑战了当前对功能磁共振成像（fMRI）的理解，这是在临床或科学环境中研究人脑的最常用手段，因此将对对这种至关重要的医疗工具的正确解释产生重大影响。