The role of area V4 in the perception and recognition of visual objects

V4区在视觉物体感知和识别中的作用

• 批准号: 8893671
• 负责人: Anitha Pasupathy
• 金额: $ 47.96万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8893671
• 关键词: Agnosia; Animal Behavior; Animals; Area; Back; Behavior; Behavior Control; Behavioral; Brain; Brain Diseases; Color; Complex; Computer Simulation; Computer Vision Systems; Custom; Data Analyses; Discrimination; Eye; Feedback; Functional disorder; Goals; Grouping; Human; Image; Lead; Lesion; Macaca; Mediating; Methods; Modeling; Monkeys; Neurons; Pathway interactions; Perception; Performance; Peripheral; Physiological; Play; Population; Population Study; Prefrontal Cortex; Primates; Process; Property; Psychology; Psychophysics; Relative (related person); Role; Schizophrenia; Shadowing (Histology); Shapes; Signal Transduction; Staging; Stimulus; Stream; Surface; Surface Properties; Techniques; Testing; Texture; Time; V4 neuron; Vision; Visual; Visual Agnosias; Visual Cortex; Visual system structure; area V4; awake; base; design; executive function; feeding; fovea centralis; imaging Segmentation; impaired capacity; neurophysiology; neurotransmission; object recognition; public health relevance; relating to nervous system; research study; response; stereoscopic; visual process; visual processing

 DESCRIPTION (provided by applicant): The human visual system parses the information that reaches our eyes into a meaningful arrangement of regions and objects. This process, called image segmentation, is one of the most challenging computations accomplished by the primate brain. To discover its neural basis we will study neuronal processes in two brain areas in the macaque monkey-V4, a fundamental stage of form processing along the occipito-temporal pathway, and the prefrontal cortex (PFC), important for executive control. Dysfunctions of both areas impair shape discrimination behavior in displays that require the identification of segmented objects, strongly suggesting that they are important for image segmentation. Our experimental techniques will include single and multielectrode recordings, behavioral manipulations, perturbation methods and computer models. In Aim 1 we will identify the neural signals that reflect segmentation in visual cortex. Using a variety of parametric stimuli with occlusion, clutter and shadows-stimulus features known to challenge segmentation in natural vision-we will evaluate whether segmentation is achieved by grouping regions with similar surface properties, such as surface color, texture and depth, or by grouping contour segments that are likely to form the boundary of an object or some interplay between these two strategies. We will test the hypothesis that contour grouping mechanisms are most effective under low clutter and close to the fovea. In Aim 2, we will investigate how feedback from PFC modulates shape responses in V4 and facilitates segmentation: we will test the longstanding hypothesis that object recognition in higher cortical stages precedes and facilitates segmentation in the midlevels of visual form processing. We will simultaneously study populations of V4 and PFC neurons while animals engage in shape discrimination behavior. We will use single-trial decoding methods and correlation analyses to relate the content and timing of neuronal responses in the two areas. To causally test the role of feedback from PFC, we will reversibly inactivate PFC by cooling and study V4 neurons. Our results will provide the first detailed, analytical models of V4 neuronal response dynamics in the presence of occlusion and clutter and advance our understanding of how complex visual scenes are processed in area V4. They will also reveal how V4 and PFC together mediate performance on a complex shape discrimination task, how executive function and midlevel vision may be coordinated during behavior and how feedback is used in cortical computation. Object recognition is impaired in visual agnosia, a dysfunction of the occipito-temporal pathway, and in dysfunctions of the PFC (e.g. schizophrenia). Results from these experiments will constitute a major advance in our understanding of the brain computations that underlie segmentation and object recognition and will bring us closer to devising strategies to alleviate and treat brain disorders in which these capacities are impaired.

 描述（由适用提供）：人类视觉系统解析了我们眼睛的信息，以有意义的区域和物体排列。该过程称为图像分割，是主要大脑完成的最挑战者计算之一。为了发现其神经元基础，我们将研究猕猴V4中两个大脑区域的神经元过程，这是沿枕topemanter途径的形式加工的基本阶段，前额叶皮层（PFC）（PFC）对执行控制很重要。两种区域的功能障碍会损害需要识别分段对象的显示器中形状的歧视行为，这强烈表明它们对于图像分割很重要。我们的实验技术将包括单一和多电极记录，行为操纵，扰动方法和计算机模型。在AIM 1中，我们将确定反映视觉皮层分割的神经信号。使用各种具有遮挡的参数刺激，杂物和阴影 - 刺激特征已知的挑战自然视觉分割的特征 - 我们将通过对具有相似表面特性的区域进行分组（例如表面颜色，纹理和深度），还是通过将这些策略构成对象的边界或两种策略之间的边界来评估分割的分割。我们将检验以下假设：在低杂波和靠近中央凹的情况下，轮廓分组机制最有效。在AIM 2中，我们将研究PFC的反馈如何调节V4中的形状响应并促进分割：我们将测试以下假设的长期假设：在视觉形式处理的中层中，较高皮质阶段的对象识别和促进分割。我们将同时研究V4和PFC神经元的种群，而动物从事形状歧视行为。我们将使用单次试验解码方法和相关分析来关联这两个领域的神经元反应的内容和时机。为了偶尔测试PFC反馈的作用，我们将通过冷却和研究V4神经元来反抗PFC。我们的结果将在遮挡和混乱的情况下提供第一个详细的，V4神经元反应动力学的分析模型，并促进我们对区域V4中复杂视觉场景如何处理的理解。他们还将揭示V4和PFC如何在复杂的形状歧视任务上介导性能，行为过程中如何协调执行功能和中级视觉以及如何在皮质计算中使用反馈。在视觉不适，枕to途径的功能障碍以及PFC功能障碍（例如精神分裂症）中，对象识别受损。这些实验的结果将构成我们对大脑计算的理解和对象识别的基础的重大进步，并将使我们更接近制定策略来减轻和治疗这些能力受损的脑部疾病。