Properties of training-induced visual recovery in cortical blindness

训练引起的皮质盲视觉恢复的特性

• 批准号: 9121240
• 负责人: Matthew Cavanaugh
• 金额: $ 3.67万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-01 至 2017-08-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9121240
• 关键词: Address; Adult; Attention; Blindness; Complex; Conscious; Contralateral; Contrast Sensitivity; Cortical Blindness; Coupled; Coupling; Cues; Data; Depressed mood; Development; Discrimination; Discrimination Learning; Effectiveness; Evaluation; Exposure to; Foundations; Functional Magnetic Resonance Imaging; Future; Goals; Grant; Impairment; Injury; Knowledge; Left; Location; Maps; Measures; Methods; Modification; Noise; Outcome; Patients; Perceptual learning; Performance; Perimetry; Population; Predisposition; Process; Property; Protocols documentation; Psychological Transfer; Psychophysics; Recovery; Regimen; Residual state; Specificity; Stimulus; Stroke; Testing; Training; Training Programs; Vision; Visual; Visual Fields; Visual Motion; Visual system structure; Work; area striata; base; blind; compare effectiveness; extrastriate visual cortex; improved; insight; patient population; programs; public health relevance; rehabilitation strategy; relating to nervous system; research study; response; retinotopic; signal processing; visual performance

 DESCRIPTION (provided by applicant): Cortical blindness (CB) results from damage to the primary visual cortex, presenting as a loss of vision in the contralateral visual field. Work from my lab and others have previously shown that visual training can recover simple and complex visual motion discriminations at trained, blind field locations in CB subjects. However, recovered contrast sensitivity and discrimination of fine direction differences are poor compared to those in intact portions of the visual field, suggesting that recovered vision is not fully functional. The main question addressed in this grant is: can these residual visual deficits be overcome in CB fields, both with respect to feature processing and spatial transfer of learning? To address this question, I have developed two specific aims to test (1) whether manipulating feature-based attention (FBA) or spatial attention (SA) will aid in overcoming residual visual deficits and (2) whether locations of training induced recovery are predicted by regions of spared retinotopic activity. In the first aim I will investigate the residual inability to perform fine direction discriminations following psychophysical training on coarse direction discrimination. I will attempt to overcome this impairment using FBA and SA coupled with visual discrimination training to recover visual performance. Both FBA and SA have been demonstrated in visual intact subjects to promote improvement of fine discrimination thresholds, and they will likely have the same effect in CB subjects. My second aim investigates the relationship between the visual field of CB subjects and retinotopic activity. Training-induced recovery is retinotopically localized to trained locations with respect to depth in the blind field, but not along the blind fild border. I will test the hypothesis that location of recovery can be predicted based on pre-training fMRI retinotopic maps and that vision can be recovered only in regions of the visual field where residual cortical activity is present. Humphrey perimetry and psychophysical measures of direction and orientation discrimination will be used to assess the spatial extent of training-induced recovery, which will be correlated with retinotopic maps obtained from fMRI. Finally, I will assess whether and to what extent retinotopic specificity of recovery deep into the blind fiel can be overcome by manipulating exogenous spatial attention. The proposed experiments will provide further insights into the properties of training-induced visual recovery in cortically blin fields, documenting the effects of attentional manipulations on training, investigating a possible mechanism by which training induced recovery occurs, and determining the spatial spread and limitations of recovered vision. A better understanding of these properties will not only improve treatment cortical blindness, but will also improve our understanding of plasticity within the adul visual system by studying to what extent visual function can recover following a large, permanent injury.

 描述（由申请人提供）：皮质盲（CB）是由初级视皮层损伤引起的，表现为对侧视野的视力丧失。我的实验室和其他人的工作以前表明，视觉训练可以恢复简单和复杂的视觉运动的歧视，在训练，盲场位置在CB科目。然而，恢复的对比敏感度和精细方向差异的辨别力与图1中的那些相比是差的。 完整的部分视野，这表明恢复的视力是不完全的功能。在这个补助金解决的主要问题是：这些残余的视觉缺陷可以克服CB领域，无论是在功能处理和空间转移的学习？为了解决这个问题，我已经开发了两个具体的目标来测试（1）是否操纵基于特征的注意力（FBA）或空间注意力（SA）将有助于克服残余的视觉缺陷和（2）是否培训诱导恢复的位置是由备用的视网膜活动区域预测。在第一个目标，我将调查剩余的无法执行精细的方向歧视后，心理物理训练的粗方向歧视。我将尝试使用FBA和SA结合视觉辨别训练来克服这种障碍，以恢复视觉表现。FBA和SA都已在视觉完整受试者中被证明可以促进精细辨别阈值的改善，并且它们在CB受试者中可能具有相同的效果。我的第二个目标是调查CB科目的视野和视网膜活性之间的关系。训练诱导的恢复是视网膜局部化的训练位置相对于深度在盲场，但不是沿着盲场边界。我将测试的假设，恢复的位置可以预测的基础上预先培训 功能磁共振视网膜定位图和视力可以恢复，只有在区域的视野，残留的皮层活动存在。Humphrey视野检查以及方向和方位辨别的心理物理测量将用于评估训练诱导恢复的空间范围，这将与从fMRI获得的视网膜定位图相关。最后，我将评估是否以及在何种程度上视网膜特异性恢复到盲野深处可以克服操纵外源性空间注意。拟议的实验将提供进一步的见解，训练诱导的视觉恢复在皮质盲场的属性，记录的注意力操纵对训练的影响，调查一个可能的机制，训练诱导的恢复发生，并确定恢复视力的空间分布和限制。更好地理解这些特性不仅可以改善皮质盲的治疗，而且还可以通过研究大面积永久性损伤后视觉功能恢复的程度来提高我们对成人视觉系统可塑性的理解。