Access to parietal action representations after stroke lesions in visual cortex

项目总结 根据物体的功能(如叉子、锤子、铅笔)识别和使用物体的能力需要 整合视觉、语义和动作知识，涵盖枕区、颞区和顶区。左顶叶 区域支持面向对象的操作的关键方面，如抓取和对象操作。这 研究活动结合使用功能磁共振成像和缺血性中风患者的行为测量来 以检验以下假设：目标1：存在一条通向 绕过初级视觉皮质处理的顶叶抓取区(AIPS)。目标2：左侧腹侧纹外核 对于视觉呈现的对象，皮质是访问操作信息所必需的。目标3A：弹道 在偏视视野中对物体的抓取动作受体积特性(大小、方位)的影响 目标。目标3B：左腹纹外区病变损害物体功能(例如，用于切割的剪刀)和干扰 从视觉输入访问操作知识。这项研究利用了功能磁共振成像(全脑)的优势 相关测量)和神经心理学(因果推理)来测试关于视觉和行动的新假说。 ‘工具’(即可操作的小对象)是解决更广泛问题的极好领域 关于感觉、运动和认知加工的整合。这是因为工具识别和工具使用 需要整合不同的感觉、运动和认知表征，以及 对刀具加工进行了较好的描述。该研究项目强调对长期存在的想法的新视角。 关于背侧和腹侧视觉通路，通过a)进行第一次系统的类型调查 关于通过绕过初级视觉皮质的视觉通路提取的对象的信息，以及由b) 研究某些顶区如何依赖腹侧流的输入才能获得正确的动作 对于给定的对象。研究活动通过测试关于不同阶段的损伤如何的假说进行了创新 影响顶叶皮质的下游处理，将神经和 研究脑损伤患者的行为测量(产生因果证据)，并通过结合 “读出”大脑区域(顶叶皮质)信息内容的单变量和多变量措施 在解剖学上远离病变的地方。这项研究促进了人们对一个大脑中的病变如何 区域干扰大脑其他部分的计算，这些计算依赖于受损区域的输入， 一般适用于脑损伤的现象(‘动力性精神错乱’)。增进对这些问题的理解 使用因果数据的基本问题对于理解大脑如何选择正确的行为具有广泛的意义 对于正确的对象，更广泛地说，对于概念组织理论和因果推理。 了解大脑如何从视觉输入中获取动作对于相关领域具有重要意义，例如 机器人学、神经假体学和基于证据的脑损伤后功能康复方法。

PROJECT SUMMARY The ability to recognize and use objects according to their function (e.g., fork, hammer, pencil) requires integration of visual, semantic and action knowledge across occipital, temporal and parietal areas. Left parietal regions support critical aspects of object-directed action, such as grasping and object manipulation. This research activity uses a combination of fMRI and behavioral measures in patients with ischemic strokes to early and extrastriate visual areas to test the following hypotheses: Aim 1: There is a visual pathway to the parietal grasp region (aIPS) that bypasses processing in primary visual cortex. Aim 2: Left ventral extrastriate cortex is necessary to access manipulation information for visually presented objects. Aim 3A: Ballistic grasping actions to objects in the hemianopic field are influenced by volumetric properties (size, orientation) of targets. Aim 3B: Left ventral extrastriate lesions impair object function (e.g., `scissors used to cut') and disrupt access to manipulation knowledge from visual input. The research leverages strengths of fMRI (whole brain correlational measure) and neuropsychology (causal inference) to test new hypotheses about vision and action. `Tools' (i.e., small manipulable objects) are an excellent domain in which to address broader questions about the integration of sensory, motor and cognitive processing. This is because tool recognition and tool use require the integration of distinct sensory, motor and cognitive representations, and the neural substrates of tool processing are well described. The research program emphasizes fresh perspectives on longstanding ideas about the dorsal and ventral visual pathways, by a) undertaking the first systematic investigation of the types of information about objects that are extracted by visual pathways that bypass primary visual cortex, and by b) studying how some parietal areas depend on inputs from the ventral stream in order to access the correct action for a given object. The research activity innovates by testing hypotheses about how lesions at different stages in the cortical visual hierarchy affect downstream processing in parietal cortex, combining neural and behavioral measures to study brain damaged patients (generating causal evidence), and by combining univariate and multivariate measures to `read out' the information content of brain regions (parietal cortex) that are anatomically remote from a lesion. The research advances understanding of how lesions in one brain region disrupt computations in other parts of the brain that depend on the damaged region for their inputs, a phenomenon (`dynamic diaschisis') that applies to brain injury generally. Advancing understanding of these basic issues using causal data has broad implications for understanding how the brain selects the correct action for the correct object, and more generally for theories of conceptual organization and causal reasoning. Understanding how the brain accesses actions from visual input has implications for related fields, such as robotics, neuroprosthetics, and evidenced based approaches for rehabilitating function after brain injury.