Neuronal Mechanisms Mediating Visual Search

介导视觉搜索的神经机制

• 批准号: 7317215
• 负责人: Robert Desimone
• 金额: $ 39.6万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7317215
• 关键词: Affect; Anatomy; Animals; Area; Attention; Attention deficit hyperactivity disorder; Automobile Driving; Behavior; Behavioral; Biological; Brain; Brain Diseases; Cells; Code; Color; Condition; Crowding; Data; Depth; Development; Discipline; Effectiveness; Environment; Eye Movements; Face; Feedback; Fire - disasters; Frequencies; Functional Magnetic Resonance Imaging; Goals; Hand; Human; Knowledge; Link; Location; Measures; Mediating; Methods; Modification; Nature; Neurobiology; Neurons; Ocular Prosthesis; Outcome Study; Pathway interactions; Performance; Personal Satisfaction; Physiological; Play; Positioning Attribute; Prefrontal Cortex; Process; Range; Rate; Relative (related person); Research; Research Personnel; Role; Scientist; Shapes; Signal Transduction; Source; Staging; Stimulus; Stream; Techniques; Testing; Time; Training; V4 neuron; Variant; Visual; Visual Cortex; Visual Fields; Visual impairment; Work; area V4; attentional modulation; base; directed attention; expectation; experience; extrastriate visual cortex; frontal eye fields; gaze; innovation; insight; novel; novel strategies; object recognition; postsynaptic; programs; receptive field; relating to nervous system; response; visual process; visual processing; visual search

DESCRIPTION (provided by applicant): A typical visual scene will contain many different objects, few of which will be relevant to the task at hand. Thus, attentional mechanisms are needed to find relevant objects and suppress distracters. An understanding of these attentional mechanisms will ultimately help in developing a visual prosthesis for people with severe visual impairments, and will also help in developing treatments for people with brain disorders affecting attention, including ADHD. The long term goal of this proposal is to not only uncover attentional influences on visual processing in the brain, but also to understand the neuronal mechanisms by which these effects occur. It is particularly important to understand how the attentional mechanism operates under naturalistic conditions, such as when we freely move our gaze to find objects based on their features (e.g. visual search, or finding a "face in a crowd"). Our focus is on visual area V4, which is an intermediate processing stage in the cortical pathway important for object recognition. New results suggest that the attentional bias in favor of behaviorally relevant stimuli may involve not only changes in the average firing rate of V4 neurons, but also the synchronous timing of V4 activity. The first specific aim is to test hypotheses about the different functional contributions of the upper and lower layers in area V4 to feature-based attention in visual search. The next aim is to establish the specific contributions of firing rates and neural synchrony to the behavioral performance of animals engaged in visual search. The third aim is to determine the contribution of prefrontal cortex to the attentional effects on V4 neuronal responses and synchrony during visual search. These aims will give us a better understanding of the functional anatomy of attention in the visual cortex, the contributions of specific biological mechanisms of attention to behavior, and the nature of top-down feedback to the visual cortex. The central hypothesis of the research program is that neurons in prefrontal cortex induce changes in both firing rates and neural synchrony in ventral stream visual areas such as area V4, and that these changes mediate the selection of relevant objects under naturalistic conditions of visual search. These hypotheses test novel ideas, but they are well supported by preliminary data, and we are well-positioned to test them since we have had many years of experience with the techniques.

描述（由申请人提供）：典型的视觉场景将包含许多不同的对象，其中很少会与手头的任务相关。因此，需要注意机制来找到相关对象并抑制干扰物。对这些注意机制的理解最终将有助于为患有严重视觉障碍的人开发视觉假体，还将有助于为影响注意力（包括ADHD）的脑疾病患者开发治疗方法。该提案的长期目标不仅要揭示对大脑视觉处理的注意力的影响，而且还要了解发生这些作用的神经元机制。了解注意力机制如何在自然主义条件下运行，例如当我们自由移动目光以根据其特征找到对象（例如，视觉搜索或在人群中找到“面孔”）时，这一点尤其重要。我们的重点是视觉区域V4，这是对物体识别重要的皮质途径中的中间处理阶段。新的结果表明，有利于行为相关刺激的注意力偏见不仅涉及V4神经元的平均点火率的变化，还涉及V4活性的同步时机。第一个具体目的是测试有关区域V4中上层和下层在视觉搜索中基于特征的关注的假设。下一个目的是确定发射率和神经同步对从事视觉搜索的动物的行为表现的特定贡献。第三个目的是确定前额叶皮层对视觉搜索过程中对V4神经元反应和同步的注意影响的贡献。这些目的将使我们更好地了解视觉皮层中注意力的功能解剖结构，特定生物学对行为的特定生物学机制的贡献以及对视觉皮层的自上而下反馈的性质。研究计划的中心假设是，前额叶皮层中的神经元在腹侧溪流视觉区域（如区域V4）中诱导触发速率和神经同步的变化，并且这些变化介导了在自然主义的视觉搜索条件下选择相关物体的选择。这些假设测试了新颖的想法，但是它们得到了初步数据的很好的支持，并且由于我们在技术方面有多年的经验，因此我们对它们进行了很好的测试。