Neural Mechanisms of Human Visual Perception

描述（申请人提供）：人类的视觉感知依赖于选择性和建设性的神经机制来组织和解释视觉信息。感知的选择性可以在双眼竞争中看到，在此过程中，每只眼睛看到不同的单眼模式。在这些条件下，感知每隔几秒钟就会在单眼图像和另一单眼图像之间选择性地交替。相反，感知的建设性本质可能最好的例证是对盲点的感知填充，在盲点中，生动的印象发生在缺乏任何输入的视觉位置。大脑究竟是如何调节这些互补的感知选择和构建过程的，我们仍然知之甚少。本项目将利用功能性磁共振成像（fMRI）研究人类视觉皮层中双眼竞争和知觉填充的神经基础。我们的中心假设是，竞争过程中的选择性感知和填充过程中的建设性感知涉及不同的神经机制，这些神经机制在视觉系统的不同层次上运作。为了研究这些问题，我们开发了特殊的行为和功能磁共振成像技术来快速可靠地定位盲点的皮层表征，在之前的研究中，我们已经表明，在竞争过程中，单眼VI表征中的功能磁共振成像活动与感知意识密切相关，这表明竞争是单眼VI神经元之间早期竞争的结果。相反，当我们立即刺激盲点周围的视网膜区域时，我们发现Vi区视觉活动存在“空洞”，而V2区则没有，这可能表明知觉填充发生在更高的视觉区域，如V2。本研究将描述竞争和填充的神经机制和视觉区域。更重要的是，它将解决关于以下问题的科学争论：1)双眼竞争是由眼间竞争还是模式竞争引起的；2)感知填充是由视觉输入的主动神经完成还是被动重新映射引起的。该项目将促进我们对人类视觉感知中选择性和建设性机制的神经组织的了解。考虑到视觉是从环境中获取信息以指导判断和行动的主要感觉，这样的研究很重要。拟议的研究不仅将解决人类视觉感知的神经基础，而且将为视觉功能障碍和神经系统疾病的研究提供信息，包括斜视，弱视（单眼视力抑制），以及由视网膜或皮质损伤引起的视野丧失的神经后果。

DESCRIPTION (provided by applicant): Human visual perception relies on both selective and constructive neural mechanisms to organize and to interpret visual information. The selectivity of perception can be seen in binocular rivalry, during which each eye views a different monocular pattern. Under these conditions, perception selectively alternates between one monocular image versus the other image every few seconds. Conversely, the constructive nature of perception may be best exemplified by perceptual filling-in of the blind spot in which vivid impressions occur in a visual location that lacks any input. Exactly how the brain mediates these complementary processes of perceptual selection and construction remains poorly understood. This project will use functional magnetic resonance imaging (fMRI) to investigate the neural basis of binocular rivalry and perceptual filling-in within human visual cortex. Our central hypothesis is that selective perception during rivalry and constructive perception during filling-in involve separate neural mechanisms that operate at different levels of the visual system. To investigate these issues, we have developed special behavioral and fMRI techniques to localize the cortical representation of the blind spot quickly and reliably, in previous studies, we have shown that fMRI activity in the monocular VI representation of the blind spot is tightly linked to perceptual awareness during rivalry, suggesting that rivalry results from early competition between monocular VI neurons. In contrast, when we stimulate the retinal region immediately surrounding the blind spot, we find evidence of a "hole" in visual activity in Vi but not in V2, perhaps suggesting that perceptual filling-in occurs in higher visual areas such as V2. The proposed research will characterize the neural mechanisms and visual areas responsible for rivalry and filling-in. More important, it will address scientific debates regarding whether: i) binocular rivalry arises from interocular competition versus pattern competition, and ii) perceptual filling-in arises from active neural completion versus passive remapping of visual inputs. This project will advance our knowledge of the neural organization of selective and constructive mechanisms in human visual perception. Such research is important given that vision serves as a primary sense for acquiring information from the environment to guide judgments and actions. The proposed studies will not only address the neural basis of human visual perception but will also inform research on visual dysfunctions and neurological disorders, including strabismus, amblyopia (suppressed vision in one eye), and the neural consequences of visual-field loss resulting from retinal or cortical injury.