Mechanisms of visuomotor transformations in the primate frontal cortex

灵长类额叶皮层视觉运动转化的机制

• 批准号: 313382-2012
• 负责人: MartinezTrujillo, JulioCesar
• 金额: $ 3.28万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=514940
• 关键词: Mechanisms; visuomotor; transformations; primate; frontal

The brain is a complex organ that received sensory signals and then produces according to the organism internal goals commands to move the muscles that execute actions. This process of sensory-to-motor transformation is complex and it has been challenging to understand the role of different brain areas in its various steps. Previous studies in monkeys have disentangled some of the basic mechanisms at the sensory and motor ends of the transformation, by identifying brain areas in which sensory and motor signals are almost exclusively encoded (e.g., sensory and motor cortices). Others have identified brain areas that contain a mix of sensory and motor signals, mainly during the execution of gaze movements (saccades) towards visual targets. Of particular interest are areas of the frontal lobe that may also play a role in learning. How are visual signals transformed into gaze commands within these areas remains poorly understood. The current proposal continues the research we have undertaken in the previous Discovery grant. We have targeted an area of the frontal cortex, the Frontal Eye Fields (FEF) as candidate for performing visuomotor transformations for gaze during complex tasks. We will test two main hypotheses. First, that visual information reaches visual neurons within the FEF, and then is transferred to visuomovement neurons that finally pass the information to movement neurons. Second, we will test the hypothesis that the FEF plays an important role in the learning of visuomotor associations. We anticipate that some FEF neurons become selective for visual cues carrying the meaning of the association and that learning occurs when these units strengthen their connectivity with movement neurons encoding the location of the intended saccadic eye movement. We will use a combination of multielectrode array recordings and behavioural measurements in awake monkeys performing visuomotor tasks. This will allow us to characterize the response and explore interactions amongst the different neuronal types within the FEF using correlation and Granger causality analyses. Our results will reveal the mechanisms of visuomotor transformation as well as the neural substrates of visuomotor learning in the primate frontal lobe.

大脑是一个复杂的器官，它接收感觉信号，然后根据有机体的内部目标产生命令，移动执行动作的肌肉。这个从感觉到运动的转换过程是复杂的，理解不同大脑区域在其不同步骤中的作用一直是一个挑战。以前对猴子的研究已经通过识别感觉和运动信号几乎唯一编码的大脑区域(例如，感觉和运动皮质)，解开了转换中感觉和运动末端的一些基本机制。其他人发现了包含感觉和运动信号混合的大脑区域，主要是在向视觉目标进行凝视运动(扫视)的过程中。特别令人感兴趣的是额叶的区域，这些区域也可能在学习中发挥作用。在这些区域内，视觉信号是如何转化为凝视命令的，目前还知之甚少。目前的提案延续了我们在之前的发现拨款中进行的研究。我们的目标是额叶皮质的一个区域，即额叶眼场(FEF)，作为执行复杂任务中凝视的视觉运动转换的候选区域。我们将检验两个主要假设。首先，视觉信息到达FEF内的视觉神经元，然后传输到视觉运动神经元，再由视觉运动神经元将信息传递给运动神经元。其次，我们将检验FEF在视觉运动联系学习中起重要作用的假设。我们预计，一些FEF神经元对带有关联意义的视觉线索变得选择性，当这些单位加强与编码预期眼跳运动位置的运动神经元的连接时，学习就发生了。我们将使用多电极阵列记录和行为测量相结合的方法，在清醒的猴子中执行视觉运动任务。这将使我们能够利用相关性和格兰杰因果关系分析来表征反应并探索FEF内不同神经元类型之间的相互作用。我们的结果将揭示视觉运动转换的机制以及灵长类动物额叶视觉运动学习的神经基础。