Neuronal Mechanisms Mediating Visual Search

介导视觉搜索的神经机制

• 批准号: 7931133
• 负责人: Robert Desimone
• 金额: $ 16.77万
• 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/7931133
• 关键词: Affect; Anatomy; Animals; Area; Attention; Attention deficit hyperactivity disorder; Automobile Driving; Behavior; Behavioral; Biological; Brain; Brain Diseases; Cells; Code; Color; Crowding; Data; Development; Discipline; Effectiveness; Environment; Eye Movements; Face; Feedback; 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; Physiological; Play; Positioning Attribute; Prefrontal Cortex; Process; 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，其中很少有与手头的任务相关的。因此，需要注意机制来找到相关物体并抑制干扰。了解这些注意力机制最终将有助于为患有严重视力障碍的人开发视觉假体，也将有助于为患有影响注意力的脑部疾病（包括多动症）的人开发治疗方法。该提案的长期目标不仅是揭示注意力对大脑视觉处理的影响，而且是了解这些影响发生的神经机制。了解注意力机制在自然条件下如何运作尤其重要，例如当我们自由地移动目光以根据其特征寻找物体时（例如视觉搜索，或在人群中寻找“面孔”）。我们的重点是视觉区域 V4，它是皮质通路中对于物体识别很重要的中间处理阶段。新结果表明，偏向于行为相关刺激的注意力偏差可能不仅涉及 V4 神经元平均放电率的变化，还涉及 V4 活动的同步时间。第一个具体目标是测试有关 V4 区域上层和下层对视觉搜索中基于特征的注意力的不同功能贡献的假设。下一个目标是确定放电率和神经同步对从事视觉搜索的动物的行为表现的具体贡献。第三个目的是确定前额皮质对视觉搜索过程中 V4 神经元反应和同步性注意力影响的贡献。这些目标将使我们更好地理解视觉皮层注意力的功能解剖、注意力特定生物机制对行为的贡献以及视觉皮层自上而下反馈的本质。该研究项目的中心假设是，前额叶皮层的神经元会引起腹侧流视觉区域（例如V4区域）的放电率和神经同步性的变化，并且这些变化介导在视觉搜索的自然条件下对相关物体的选择。这些假设测试了新颖的想法，但它们得到了初步数据的充分支持，而且我们有能力测试它们，因为我们在这些技术方面拥有多年的经验。