Perceptual And Motor Decisions In The Primate Brain

我的研究兴趣是了解感知和行动是如何从大脑活动中产生的。我的主要方法是记录执行各种视觉搜索和强迫选择辨别任务的猴子大脑中的神经活动。我的大部分研究都集中在额叶眼区，它位于前额叶皮质，参与将视觉信息转化为移动眼睛的命令。这个项目的目标是了解大脑如何决定将目光定向到哪里，并了解定向视觉注意的神经基础。 我假设，通过将视觉场景的神经表示与观察者S关于世界的知识相结合，额部眼场起到了地形图的作用，代表了视觉场景中每个物体的相对重要性。由此产生的地形表示对应于许多定向空间注意和扫视目标选择的理论模型中所特有的显著图。如果这一假设是正确的，那么额叶眼场中最高活动所代表的位置对应于隐蔽空间注意的聚光灯，并以概率的方式引导眼跳。在Thompson等人的研究中。(2004)和佐藤等人的。(2003)我们对这一理论进行了检验，并证实了横跨前额眼场的活动模式基于物体的内在视觉突显以及观察者的知识和期望形成了一幅扫视概率图。在Schall等人的研究中。(2003)我们发现，额叶眼场神经元的感受野具有中心-环绕结构，反映了注意分配的空间差异。Schall等人对前部眼场在视觉处理和眼跳产生中的作用进行了综述。(2003)。在Thompson和Bichot(2004)中，我们综合了许多实验的证据，表明额部眼场确实是视觉显著的地图，而不仅仅是产生眼动的运动地图。在Thompson(2004)中，我提出的证据表明，在没有眼球运动的情况下，前视区域的活动可能有助于增强与定向视觉注意相关的视觉加工。 这些研究扩展了我们对额叶眼场的理解，远远超出了它在控制眼球运动中的常见作用。有了这些知识，我们可以设计实验来研究感觉信息在大脑中的流动，因为它被转化为感知和行动。这项工作帮助我们了解大脑如何集中注意力做出知觉决定和指导行为的机制，这对于能够理解和治疗人类的注意力相关障碍是必要的。

My research interest is to understand how perception and action emerge from brain activity. My main approach is to record neural activity in the brains of monkeys performing various visual search and forced-choice discrimination tasks. Most of my research has focused on the frontal eye field, which is located in the prefrontal cortex and participates in the transformation of visual information into commands to move the eyes. The goal this project is to understand how the brain decides where to direct gaze and to understand the neural basis of directed visual attention. I hypothesize that the frontal eye field functions as a topographic map that represents the relative importance of every object in the visual scene by integrating the neural representation of the visual scene with the viewer?s knowledge about the world. The resulting topographic representation corresponds to the salience map that is featured in many theoretical models of directed spatial attention and saccade target selection. If this hypothesis is correct, then the location represented by the highest activity in the frontal eye field corresponds to the spotlight of covert spatial attention and directs saccades in a probabilistic manner. In Thompson, et al. (2004) and in Sato et al. (2003) we put this theory to the test and confirm that the activity pattern across the frontal eye field forms a map of saccade probability based on the intrinsic visual salience of objects and the knowledge and expectations of the viewer. In Schall et al. (2003) we show that the receptive fields of frontal eye field neurons have a center-surround organization that reflects spatial variations in the allocation of attention. The role of the frontal eye field in visual processing and saccade generation is reviewed in Schall et al. (2003). In Thompson and Bichot (2004), we synthesize the evidence from many experiments to show that the frontal eye field is indeed a map of visual salience and not just a motor map for the generation of eye movements. In Thompson (2004) I present evidence showing that the activity in frontal eye field likely contributes to the spotlight of enhanced visual processing associated with directed visual attention without eye movements. These studies have extended our understanding about the frontal eye field far beyond its familiar role in controlling eye movements. With this knowledge we can design experiments to investigate the flow of sensory information through the brain as it is transformed into perception and action. This work helps us understand the mechanisms of how the brain focuses attention to make perceptual decisions and guide behavior, which is necessary to be able to understand and treat attention-related disorders in humans.