The Occipital Cortex in Cross-Modal Sensory Processing

描述(由申请人提供)：目前的证据表明，枕叶皮质(通常与视觉感知有关)积极参与非视觉感觉任务。例如，在有视力和失明的人身上都已经证明，这一区域与通过触摸获得的感觉信息的处理有关。本研究的目的是研究跨模式感觉相互作用的神经生理学和神经可塑性。具体而言，这项研究有三个目标：(目标1)。在先天失明和视力正常的个体中，枕叶(视觉)皮质区域在触觉空间辨别任务中扮演什么角色？(目标2)有视力和失明的人对复杂物体和视觉场景(例如，脸和房子)的触觉探索是否激活了已知的更高层次的视觉区域？(目的3)触觉刺激是否调节枕叶皮质功能？我们将使用功能磁共振成像和经颅磁共振仪来探讨这些问题。受试者将执行空间辨别和物体识别任务，以触觉呈现的刺激(简单的凸起的点纹理图案和复杂的物体，如脸)，功能磁共振将被用来绘制和比较在这些触觉任务中激活的皮层区域，在视力正常和失明的人中。在第二组实验中，我们将评估在跨模式视觉-触觉任务中枕叶皮质活动和功能的调节。TMS将被用来诱导和评估作为同时触觉刺激功能的磷化氢知觉的变化。应聘者希望学习、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。拟议的实验将有助于我们理解物体在视觉大脑中是如何呈现的，以及从触摸中获得的信息如何有助于这一过程。此外，在盲人中比较这些过程将有助于揭示在缺乏视觉的情况下物体表征背后的自适应机制。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.