The Occipital Cortex in Cross-Modal Sensory Processing

描述（由申请人提供）：目前的证据表明枕叶皮层（通常与视觉知觉相关）积极参与非视觉感觉任务。例如，在视力正常和失明的个体中，这一区域与通过触摸获得的感觉信息的处理有关。本研究的目的是探讨跨模态感觉相互作用的神经生理学和神经可塑性。具体来说，本研究有三个目标：（目标1）。在先天失明和视力正常的个体中，枕部（视觉）皮质区在触觉空间辨别任务中起什么作用？（目标2）正常人和盲人对复杂物体和视觉场景（如脸和房子）的触觉探索是否激活了已知的高阶视觉区域？（目标3）触觉刺激是否调节枕皮质功能？我们将利用功能磁共振成像和经颅磁刺激来探究这些问题。受试者将在触觉刺激（简单的凸起点纹理图案和复杂的物体，如人脸）下执行空间辨别和物体识别任务，fMRI将用于绘制和比较视力正常和失明者在这些触觉任务中激活的皮质区域。在第二组实验中，我们将评估在跨模态视觉-触觉任务中枕皮质活动和功能的调节。经颅磁刺激将被用来诱导和评估作为同时触觉刺激功能的光幻视感知的变化。候选人希望学习、掌握并结合fMRI和TMS技术，目标是成为一名独立的临床科学家。所提出的实验将有助于我们理解物体是如何在视觉大脑中呈现的，以及从触摸中获得的信息是如何有助于这一处理的。此外，在盲人中比较这些过程将有助于揭示在没有视觉的情况下物体表征的自适应机制。这些结果可能会对盲人和视障人士的康复和教育产生影响。

DESCRIPTION (provided by applicant): Current evidence suggests that the occipital cortex (normally associated with visual perception) actively participates in non-visual sensory tasks. For example, it has been demonstrated both in sighted and blind individuals that this area is implicated in the processing of sensory information obtained through touch. The purpose of this research proposal is to investigate the neurophysiology and neuroplasticity of cross-modal sensory interactions. Specifically, the study has three aims: (Aim 1). In congenitally blind and sighted individuals, what roles do occipital (visual) cortical areas play in tactile spatial discrimination tasks? (Aim 2) Does the tactile exploration of complex objects and visual scenes (e.g., faces and houses) by sighted and blind individuals activate known higher-order visual areas? (Aim 3) Does tactile stimulation modulate occipital cortex function? We will employ fMRI and TMS to pursue these questions. Subjects will perform spatial discrimination and object recognition tasks to tactile presented stimuli (simple raised dot texture patterns and complex objects such as faces), fMRI will be used to map and compare the cortical areas activated during these tactile tasks in the sighted and blind. In a second set of experiments, we will assess the modulation of occipital cortex activity and function during a cross-modal visuo-tactile task. TMS will be used to induce and assess changes in phosphene perception as a function of simultaneous tactile stimulation. The candidate wishes to learn, master and combine the techniques of fMRI and TMS with the goal of becoming an independent clinician-scientist. The proposed experiments will contribute to our understanding as to how objects are represented within the visual brain and how information obtained from touch contributes to this processing. Furthermore, comparing these processes in the blind will help uncover the adaptive mechanisms underlying object representation in the absence of vision. These results are likely to have implications for both the rehabilitation and education of the blind and visually impaired.