Anticipatory Hemodynamic Signals in Primary Visual Cortex

项目总结 该实验室的长期目标是在大脑皮层早期了解视觉处理的神经机制。 路径。为此，实验室从猕猴的视皮层记录中使用了一种内源性信号的组合 当动物执行视觉任务时，光学成像和电生理学。 这个项目源于早期的工作，表明V1(初级视觉皮质)成像信号在警觉、任务- 订婚猕猴有两个组成部分。其中一个成分与刺激和V1神经元活动有关。 另一个成分--强度相当--是一种独立于局部尖峰的新的任务相关信号。 后来的研究表明，当动物执行刻板印象的任务时，与任务相关的信号可以被移除 线性地从刺激诱发信号，然后可以与特别高的可靠性(&gt；90%)关联到局部 扣球。另一方面，与任务相关的信号受到奖励大小、任务等因素的强烈调制 结构和表现，暗示了它作为一种形式的唤醒或注意的作用，独立于局部尖峰。 这些结果是在我上一次拨款的支持下获得的。目前的提案是我的 要求对同一赠款进行竞争性续签。 这个目前的项目有两个目标，这两个目标源于上面的观察。第一个目标是将 观察到刺激诱发成像和尖峰信号之间的联系，这是解释大脑图像的一个广泛原则。 这将对解释功能磁共振成像有价值，功能磁共振成像是最广泛使用的神经科学研究工具之一。 第二个目标是定义控制任务相关信号的因素以及该信号对 性能。这一目标有望提供有关注意力或唤醒的新的大脑机制的见解， 以及注意力障碍的病因，如ADD和ADHD。 这项建议的基础上的新发现是由于在 我们实验室，连续双波长本征信号光学成像，结合电极 录音，警觉的猕猴。对于成像，一个波长，优先吸收在 氧合血红蛋白，监测血液中的氧合作用；另一个波长，在含氧量相同的情况下吸收 和脱氧血红蛋白，测量血容量。同时的电极记录给出了 对潜在神经元活动的电生理测量。连续记录使其能够 区分正在进行的信号和刺激引起的反应。这项技术将构成 当前项目，提供了一个独特的工具组合来回答手头的问题。

PROJECT SUMMARY The long-term goal of the lab is to understand the neural mechanisms of visual processing early in the cortical pathway. To this end the lab records from rhesus macaque visual cortex using a combination of intrinsic-signal optical imaging and electrophysiology while the animals perform visual tasks. This project derives from earlier work showing that V1 (primary visual cortex) imaging signals in alert, task- engaged macaques have two components. One component is related to stimulation and V1 neuronal activity. The other component - of comparable strength - is a novel task-related signal independent of local spiking. Later work showed that when the animal performs stereotyped tasks, the task-related signal can be removed linearly from stimulus-evoked signals which can then be related with particularly high reliability (>90%) to local spiking. The task-related signal, on the other hand, is strongly modulated by factors such as reward size, task structure and performance, suggesting its role as a form of arousal or attention independent of local spiking. These results were obtained using the support of my last grant. The current proposal is a resubmission of my request for a competitive renewal of the same grant. This current project has two goals that derive from the above observations. The first goal is to generalize the observed link between stimulus-evoked imaging and spiking, as a broad principle for interpreting brain images. This would be valuable for the interpretation of fMRI, one of the most widely used neuroscience research tools. The second goal is to define the factors controlling the task-related signal and the effect of this signal on performance. This goal is expected to provide insights about a novel brain mechanism of attention or arousal, as well as the etiology of attentional disorders such as ADD and ADHD. The novel findings at the base of this proposal were obtained as a result of an 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, absorbed preferentially in oxygenated hemoglobin, monitors blood oxygenation; the other wavelength, absorbed equally in oxygenated and deoxygenated hemoglobin, measures blood volume. The simultaneous electrode recordings give an electrophysiological measure of the underlying neuronal activity. The continuous recording makes it possible 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.