Perceptual And Motor Decisions In The Primate Brain

我的研究兴趣是了解主观感知和自愿运动动作是如何从大脑活动中产生的。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我们如何做出感知决策，选择在哪里直接注视，并了解定向视觉注意的神经基础。 我们的实验结果表明，额叶眼场的功能作为一个视觉显着地图，地形表示的相对重要性的每一个对象在视觉场景中，为指导注意和眼球运动的目的（综述在参考文献1）。我们假设，在额叶眼场的显着性地图对应于显着地图的特点，在许多理论模型的定向空间注意和眼跳目标选择。正如理论模型所预测的那样，我们发现，在不同难度的视觉搜索任务中，额叶眼场的活动模式不仅可以识别下一次眼跳的目标，而且还对应于做出眼跳选择的行为概率（参考文献2）。这是通过整合视觉场景中自下而上的物理显著性与观众自上而下的知识和目标来实现的（参考文献2）。 认知神经科学的一个突出问题是，我们如何能够在不移动眼睛的情况下将视觉注意力集中在特定的物体和位置上。多条证据表明，在扫视之前的额眼场的空间选择性活动与眼球运动的产生无关（参考文献3）。我们已经扩展了这一证据，以表明在没有任何眼跳规划证据的情况下，额叶眼野中视觉反应神经元的活动（而不是眼跳相关运动神经元）对应于内隐空间注意的轨迹（参考文献4）。 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 subjective perception and voluntary motor actions 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 we make perceptual decisions, choose where to direct gaze and to understand the neural basis of directed visual attention. The results of our experiments demonstrate that the frontal eye field functions as a visual salience map, a topographic representation of the relative importance of every object in the visual scene, for the purpose guiding attention and eye movements (reviewed in ref. 1). We hypothesize that the salience map in the frontal eye field corresponds to the salience map featured in many theoretical models of directed spatial attention and saccade target selection. As predicted by the theoretical models, we showed that the pattern of activity across the frontal eye field not only identifies the target of the next saccade, but also corresponds to the behavioral probability of making a saccade choice in visual search tasks with varying difficulty (ref. 2). This is accomplished by integrating the bottom-up physical salience present in the visual scene with the top-down knowledge and goals of the viewer (ref. 2). One of the outstanding questions of cognitive neuroscience is how we are able to focus visual attention on specific objects and locations without moving our eyes. Multiple lines of evidence suggest that the spatially selective activity in the frontal eye field that precedes saccades is dissociated from the production of eye movements (reviewed in ref. 3). We have extended this evidence to show that the activity of visually responsive neurons in the frontal eye field, but not saccade related movement neurons, corresponds to the locus of covert spatial attention without any evidence of saccade planning (ref. 4). 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.