Neural mechanisms of long-term plasticity in human visual cortex

摘要 神经可塑性是视力障碍康复的关键。然而，成年人的视觉神经可塑性 人们对此仍然知之甚少。这在初级视觉皮质(V1)中尤其如此，在那里 产生持久的成人神经可塑性还没有完全确定。建议数 研究旨在通过研究McCollough效应的神经基础来克服这一障碍 (我)，一种通过观看彩色定向图案而产生的视觉错觉，导致黑白 图案要看起来五颜六色。ME可以持续数周，这表明它产生了持久的 视觉系统的变化。产生它的神经轨迹和机制仍在争论中， 然而。行为学研究表明，ME可能出现在视觉处理的非常早期的水平。 然而，过去的神经成像结果未能支持这一说法，而且特定的神经 产生Me的亚群还没有确定。当前的提案包含一个 使用功能磁共振成像对ME进行全面研究，以澄清其鲜为人知的神经基础。在……里面 目标1，多变量模式分析将测试ME背后的神经群组是否位于 在V1中。将对分类器进行训练，以区分V1中来自黑白的活动模式 对比彩色图案，使用在ME诱导之前收集的数据。如果V1是ME的轨迹，那么 在其归纳之后，相同的分类器应该将对黑白图案的反应分类为 丰富多彩的，与之相匹配的感觉。AIM 2将使用超高分辨率fMRI来测试 一只眼诱导的ME定位于含有选择性神经元的眼优势柱 眼睛，如行为工作所暗示的。高分辨率数据将使用 正演模拟技术，理清了不同信号的相对响应和增益变化 对颜色敏感的神经细胞。总之，这些实验将检验这样一种假设，即 McCollough效应产生于对眼睛和颜色选择性的种群的增益变化 V1区神经元，显示出成人初级视皮层的前馈神经可塑性。这 工作是凯瑟琳·E·M·特雷格勒斯博士研究、培训和职业发展计划的一部分， 由史蒂芬·恩格尔博士和斯蒂芬·恩格尔博士共同赞助，在明尼苏达大学进行。 谢丽尔·奥尔曼。这项工作是三名研究人员之前研究的合乎逻辑的延伸，以及 明尼苏达大学为开展这项工作提供了理想的环境。拟议的研究 将增进对神经可塑性的了解，并为申请者的独立 她打算将她在长期适应方面的工作转化为临床应用。为 例如，可以开发类似于ME的范例来平衡双眼的增益 弱视，或改善颜色异常观察者的颜色对抗信号的增益。

Summary Neuroplasticity is key to rehabilitation from visual deficits. Yet, visual neural plasticity in adults remains poorly understood. This is especially true in primary visual cortex (V1), where methods for producing long-lasting adult neural plasticity have yet to be thoroughly established. The proposed research aims to overcome this roadblock by investigating the neural bases of the McCollough Effect (ME), a visual illusion produced by viewing colored, oriented patterns that causes black and white patterns to appear colorful. The ME can endure for weeks, indicating that it produces long-lasting changes in the visual system. The neural loci and mechanisms producing it remain under debate, however. Behavioral work suggests that the ME likely arises at a very early level of visual processing. However, past neuroimaging results have failed to support this claim, and the specific neural subpopulations that produce ME have yet to be identified. The current proposal contains a comprehensive investigation of the ME using fMRI to clarify its poorly understood neural bases. In Aim 1, multivariate pattern analysis will test whether neural populations underlying the ME are located in V1. A classifier will be trained to distinguish patterns of activity in V1 arising from black and white vs colorful patterns, using data gathered prior to induction of the ME. If V1 is the locus of the ME, then following its induction, the same classifier should categorize responses to black and white patterns as colorful, matching perception. Aim 2 will use ultra-high-resolution fMRI to test whether effects of an ME induced in one eye localize to ocular dominance columns containing neurons selective for that eye, as suggested by behavioral work. The high-resolution data will be further characterized using a forward modeling technique that disentangles the relative responses and gain changes of different color-sensitive neural populations. Together, these experiments will test the hypothesis that the McCollough Effect arises from gain changes in populations of eye- and color- selective neurons in V1, demonstrating feed-forward neural plasticity in adult primary visual cortex. This work is part of a research training and career development plan for Dr. Katherine E.M. Tregillus, conducted at the University of Minnesota under the co-sponsorship of Dr. Stephen Engel and Dr. Cheryl Olman. The work is a logical extension of previous research from the three investigators, and the University of Minnesota provides an ideal environment for carrying it out. The proposed research will advance understanding of neuroplasticity and provide the basis for the applicant’s independent career, where she intends to translate her work on long-term adaptation to clinical applications. For example, paradigms similar to the ME could be developed to balance the gain of the two eyes in amblyopia, or to improve the gain of color-opponent signals in color anomalous observers.