Long-range processing in dorsal-occipital cortex

描述：(申请人提供)许多组织和职能 人类大脑皮层的区域开始被理解，特别是在 感觉处理区域，如枕叶。这项提案的重点是 枕叶皮质最不为人所知的部分，即其背外侧部分。这个 这一区域周围的枕区、颞区和顶区很好 尽管人们对其进行了研究，但它的性质在很大程度上是模糊的。例如，背外侧 在功能磁共振成像(FMRI)中，节段很少或没有显示视网膜定位图 磁共振成像)研究显示多达9个内侧性和腹侧性视网膜病变 枕叶皮质的区域。关于这一功能的几个提示 背外侧区提示它可能参与了 各种类型的对象处理所需的配置连接。 这些过程包括图案的自相似性、对称性和格式塔 两性关系。这一有趣的观点表明，这种构型 连接被处理，既不是在已知的视网膜区域，也不是在 枕颞部腹侧的优势物体反应区 大脑皮层。尤其是，各种类型的对称性构成了 基于似乎很有吸引力的数学运算符的配置属性 直接影响到知觉。 了解枕外侧皮质功能的一个关键动机 (LoC)是由于它的血液供应来自 大脑后动脉(PCA)。我们有一个特别的缺陷 在该动脉分支梗塞的患者中发现一种 对其他随机图案的对称性感知的具体损失(但最小 视野损失)，暗示了用于处理的高级皮质轨迹 图案对称性。对LOC功能的了解将使 开发特定功能损失的测试并改进管理 这样的病人。 该提案致力于四个项目。首先，我们将构建一组 根据功能磁共振研究，已知的刺激可以激活部分LOC。接下来我们将 关注对称性在物体处理中的作用，我们已经发现 主要位于枕中回(在LOC上)。此外， 在对称性处理中的皮质功能磁共振敏感性将在 确定各种类别的天然和人造物体是否关键 对称性的长程处理机制的一些方面是基于 视觉形象中的对称性或从任何角度推广到物体对称性 角度，或特定于特定对象(例如面)。第三种功能磁共振成像 该项目将开发探测刺激，以确定刺激敏感性 对于与推定区域相邻的对称区域的其他皮质区域 其功能仍是个谜的处理。这些探测刺激将涉及 各种视觉形态的远程空间交互和 物体和面孔加工过程中的构形效应。决赛 该项目将引入一个临床组件，量化对称性失明 有相关损害的神经科患者，并进行对照研究 在匹配的对照组中。

DESCRIPTION: (provided by applicant) The organization and functions of many regions of the human cortex are beginning to be understood, particularly in sensory processing areas such as the occipital lobe. This proposal focuses on the least-known part of occipital cortex, its dorsolateral segment. The occipital, temporal and parietal areas surrounding this region are well studied, yet its properties are largely obscure. For example, the dorsolateral segment shows little or no retinotopic mapping in fMRI (functional Magnetic Resonance Imaging) studies that reveal up to 9 medial and ventral retinotopic areas in the occipital cortex. The few hints as to the function of this dorsolateral area suggest that it may be involved in the processing of the configurational connections required for object processing of various types. These processes include pattern self-similarity, symmetry and Gestalt relationships. This interesting viewpoint suggests that such configurational connections are processed, neither in a known retinotopic area nor in the predominant object-responsive area in the ventral parts of occipitotemporal cortex. Symmetries of various types, in particular, constitute a configurational property based on mathematical operators that seem to appeal directly to perception. A key motivation for understanding the functions of lateral occipital cortex (LOC) is that it is subject to local damage by virtue of its blood supply from the posterior cerebral artery (PCA). One particular deficit that we have identified in patients with infarctions of branches of this artery is a specific loss in symmetry perception of otherwise random patterns (but minimal visual field losses), implying a high-level cortical locus for the processing of pattern symmetries. This knowledge of the functions of LOC will allow the development of tests for particular functional losses and improved management of such patients. The proposal is devoted to four projects. First we will construct a battery of stimuli known to activate parts of LOC based on fMRI studies. Next we will focus on the role of symmetry in object processing, which we have found to be localized principally to the middle occipital gyrus (on the LOC). Further, the cortical fMRI sensitivities in symmetry processing will be compared across various classes of natural and artificial objects to determine whether the key aspects of the long-range processing mechanisms for symmetry are based on symmetry in the visual imageor generalized to object symmetry from any viewing angle, or are specific to particular objects such as faces. The third fMRI project will be to develop probe stimuli to determine stimulus sensitivities for other cortical regions adjacent to the putative area for symmetry processing whose functions remain mysterious. These probe stimuli will involve long-range spatial interactions of various visual modalities and configurational effects in the processing of objects and faces. The final project will introduce a clinical component, quantifying symmetry-blindness in neurological patients with relevant lesions, together with comparison studies in matched controls.