Population receptive field analysis in subjects with area V1+ lesions.

V1 区病变受试者的群体感受野分析。

• 批准号: 8785684
• 负责人: Stelios Manolis Smirnakis
• 金额: $ 38.34万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8785684
• 关键词: Age; Area; Behavioral; Blindness; Blood Circulation; Brain; Brain Injuries; Bypass; Chronic; Complex; Contralateral; Cortical Blindness; Data; Discrimination; Environment; Exhibits; Figs - dietary; Functional Magnetic Resonance Imaging; Future; Health; Hemianopsia; Hemorrhage; Human; Image; Individual; Infarction; Injury; Lesion; Location; Maps; Measures; Mediating; Methodology; Methods; Monkeys; Motion; Motion Perception; Pathway interactions; Patients; Perception; Performance; Perimetry; Population; Population Study; Property; Quadrantanopia; Quality of life; Reading; Recovery; Rehabilitation therapy; Residual state; Resistance; Scotoma; Sector Scotomas; Stimulus; Stroke; Testing; Training; Traumatic Brain Injury; Vision; Visual; Visual Cortex; Visual Fields; Visual Motion; Visual Perception; Visual system structure; area V1; area striata; clinically significant; cohort; density; extrastriate; extrastriate visual cortex; imaging modality; improved; information processing; motion sensitivity; novel strategies; receptive field; rehabilitation paradigm; rehabilitation strategy; standard measure; visual information; visual map; visual performance; visual process; visual processing; visual stimulus

DESCRIPTION (provided by applicant): Visual malfunction is a common corollary of stroke and several other types of cortical injury. Posterior circulation infarcts, hemorrhages or traumati brain injury often produce varying degrees of damage to visual cortical networks, including the primary visual cortex, resulting in partial or complete homonymous hemianopias or quadrantanopias. The most common clinically significant visual cortical injury involves the primary visual cortex (V1). V1 is the chief relay of visual input to higher (extra striate) cortica areas and V1 lesions result in a dense contralateral scotoma within which visual perception is severely impaired. The resulting visual deficit is long thought to be highly resistant to rehabilitation, i.e. essentially irreversible. Hope, however, may not be entirely lost. Under carefully controlled conditions a limited capacity to process visual attributes such as motion often persists inside scotomas induced by V1 lesions, both in humans and monkeys ("blindsight"). Blindsight performance improves with training (Weiskrantz L, Prog Brain Res, 144:229-41, 2004; Huxlin et al., J Neurosci. 29(13):3981-91, 2009) raising the hope that better rehabilitation strategies may one day be able to increase the strength of V1-bypassing pathways to partially compensate for the loss of V1 input. Visual rehabilitation however remains challenging and the capacity of individual patients for visual rehabilitation highly variable (fig.3). It is important to understand which areas of the visual field are more amenable to rehabilitation and to study possible mechanisms underlying recovery. Functional magnetic resonance imaging (fMRI) can be used to map population receptive field (pRF) properties in normal visual cortex (Dumoulin et al., J Neurosci, 2008). This offers a unique opportunity to characterize in detail, voxel by voxel, how pRFs in spared visual areas are organized following area V1+ injuries. However, in order to do so, the pRF mapping methodology has to be refined to eliminate biases that occur in pRF estimation near the border of a perceptual scotoma (fig. 1, 5, 6). We will study a patient cohort with chronic hemianopia and quadrantanopia as a result of V1+ lesions and age-matched controls. Specific aim #1 will develop a direct method of estimating pRF topography that is less prone to bias (figs 1, 5, 6). Specific aim #2 will characterize how visual field representation and pRF properties in spared visual areas differ in subjects with chronic V1+ lesions compared to controls. The capacity of spared visual areas to be modulated from visual field locations within the perceptual scotoma will identify locations more amenable to rehabilitation. Specific aim #3 will test the hypothesis that rehabilitative training in visual moton perception improves performance by increasing the sensitivity of the motion selective complex (hV5/MT+) to visual motion stimuli. This effect will be particularly strong in regions of the scotoma that can visually modulate area hV5/MT+ before training (SA #2). Overall, our approach will characterize how downstream areas adjust to chronic V1+ injury, and will suggest new ways to guide rehabilitative training in the future.

描述（由申请人提供）：视觉功能障碍是中风和其他几种皮质损伤的常见必然结果。后循环梗死、脑梗死或创伤性脑损伤通常对视觉皮层网络（包括初级视觉皮层）产生不同程度的损伤，导致部分或完全的同侧偏盲或象限性偏盲。最常见的具有临床意义的视皮层损伤涉及初级视皮层（V1）。V1是视觉输入到更高（纹外）皮质区的主要中继，V1病变导致对侧暗点密集，其中视觉感知严重受损。由此产生的视力缺陷长期以来被认为是高度难以康复的，即基本上是不可逆的。然而，希望可能不会完全丧失。在仔细控制的条件下，处理视觉属性（如运动）的有限能力通常持续存在于人类和猴子（“盲视”）中由V1病变引起的暗点内。失明表现随着训练而改善（Weiskrantz L，Prog Brain Res，144：229-41，2004; Huxlin等人，神经科学杂志29（13）：3981-91，2009），这增加了更好的康复策略有朝一日能够增加V1旁路通路的强度以部分补偿V1输入的损失的希望。然而，视力康复仍然具有挑战性，个体患者的视力康复能力差异很大（图3）。重要的是要了解视野的哪些区域更适合康复，并研究潜在的恢复机制。功能性磁共振成像（fMRI）可用于绘制正常视皮层中的群体感受野（pRF）特性（Dumoulin等人，J Neurosci，2008）。这提供了一个独特的机会来详细描述，逐体素，在V1+区域损伤后，备用视觉区域中的pRF是如何组织的。然而，为了做到这一点，必须改进pRF映射方法，以消除在感知盲点边界附近的pRF估计中出现的偏差（图1、5、6）。我们将研究一组因V1+病变而患慢性偏盲和象限盲的患者和年龄匹配的对照组。具体目标#1将开发一种估计pRF形貌的直接方法，该方法不易产生偏差（图1、5、6）。具体目标#2将描述与对照组相比，慢性V1+病变受试者的备用视觉区的视野表现和pRF特性如何不同。从感知暗点内的视野位置调制备用视觉区域的能力将确定更适合康复的位置。具体目标#3将测试以下假设：视觉运动感知的康复训练通过增加运动选择复合体（hV 5/MT+）对视觉运动刺激的敏感性来改善表现。这种效果在训练前可以视觉调节区域hV 5/MT+的暗点区域中将特别强（SA#2）。总的来说，我们的方法将描述下游区域如何适应慢性V1+损伤，并将提出新的方法来指导未来的康复训练。