Perceptual And Motor Decisions In The Primate Brain

我的研究兴趣是了解感知和行动如何从大脑活动中产生。我的主要方法是记录猴子在执行各种视觉搜索和强迫选择辨别任务时大脑中的神经活动。我的大部分研究都集中在额叶眼区，它位于前额叶皮层，参与将视觉信息转化为移动眼睛的命令。该项目的目标是了解大脑如何决定将目光投向何处，并了解定向视觉注意的神经基础。 我假设，额眼场功能作为一个地形图，表示在视觉场景中的每一个对象的相对重要性，通过整合与观众的视觉场景的神经表征？关于世界的知识。由此产生的地形表示对应的显着性地图，在许多理论模型的定向空间注意和眼跳目标选择的功能。如果这一假设是正确的，那么由前眼场中的最高活动所表示的位置对应于内隐空间注意的聚光灯，并且以概率的方式引导扫视。在Thompson等人（2004）和Sato等人（2003）中，我们对这一理论进行了测试，并证实了在物体的内在视觉显著性以及观看者的知识和期望的基础上，穿过前眼场的活动模式形成了眼跳概率图。在Schall et al.（2003）中，我们发现额叶眼野神经元的感受野具有中心-环绕组织，反映了注意力分配的空间变化。Schall等人（2003年）综述了额眼场在视觉处理和扫视产生中的作用。在Thompson and Bichot（2004）中，我们综合了许多实验的证据，证明了前眼场确实是视觉显著性的地图，而不仅仅是产生眼球运动的运动地图。在Thompson（2004）中，我提出的证据表明，额叶眼场的活动可能有助于增强与定向视觉注意相关的视觉处理的聚光灯，而无需眼球运动。 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熟悉作用。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。这项工作有助于我们了解大脑如何集中注意力以做出感知决策和指导行为的机制，这对于理解和治疗人类的注意力相关疾病是必要的。

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.