Systematic Psychophysical Investigation of Visual Learning

 描述（由申请人提供）：这是目前资助的一年R 01赠款（EY 019466）的更新建议。视知觉学习（VPL）被定义为作为视觉体验的结果的视觉任务表现的长期增强，被认为是视觉和大脑可塑性的表现，并且被视为改善由于视觉障碍而退化的视觉的有希望的工具。在为期一年的资助期内，我们在澄清自愿离职的特殊性方面取得了重大进展。 然而，我们尚未解决一个重要问题：视觉系统如何具有足够的可塑性以适应环境变化，但又足够稳定以保护现有的视觉信息不被新信息取代？我们的长期目标是解决VPL的这一困境。视觉的发展研究通过设置一个窗口（关键期）来解决这个难题，在这个窗口期间，视觉系统在人的早期生活中是高度可塑的。这启发了我们对成人VPL可塑期机制的研究。我们发现VPL有两个塑性期。短期可塑性期可在每次视觉训练期间开始，并在训练结束后持续不到一小时。长期可塑性期可能持续至少几天，在此期间，视觉处理的重组逐渐发生，直到训练任务的性能水平饱和。因此，我们需要分别研究这两个时期的机制。 在目标1中，我们将进行系统的心理物理调查，以更好地了解VPL的两个可塑性时期。我们发现3小时单眼剥夺可能通过消除眼间抑制来增强单眼加工的可塑性，而奖赏启动则以递减的方式增强双眼加工的可塑性。我们将研究3小时MD和奖励启动如何影响这两个可塑性时期的可塑性和稳定性。 在目标2中，我们将研究兴奋性和抑制性加工在两个可塑性阶段中的作用。视觉关键期的开始和结束与兴奋性与抑制性信号的比率（E/I比率）的变化有关。我们 将解决的问题是否以及如何在VPL的两个可塑性时期与成人也涉及到E/I比值的变化，通过磁共振波谱。 强有力的初步结果使我们的观点，从目标1和2的结果将是一致的和建设性的整合，使两个可塑性时期的功能和神经机制将得到更好的澄清。研究结果还将用于制定有效的视觉障碍干预措施。虽然VPL很可能与视觉区域内外的变化有关，但作为我们的初步方法，我们将重点研究本提案中的视觉区域。

 DESCRIPTION (provided by applicant): This is a renewal proposal for the currently funded one-year R01 grant (EY019466). Visual perceptual learning (VPL) is defined as a long-term enhancement of visual task performance as a result of visual experience, is regarded as a manifestation of visual and brain plasticity and is seen as a promising tool with which to improve vision that has been degraded due to visual disorders. Over the one-year funding period, we have made significant progress in clarifying specificity of VPL. However, we have yet to address an important question: How can the visual system be sufficiently plastic to adapt to environmental changes, but stable enough to protect existing visual information from being replaced with new information? Our long-term goal is to resolve this dilemma in VPL. Developmental studies of vision have resolved the dilemma by setting a window (critical period) during which the visual system is highly plastic in one's early life. This inspires us to investigae the mechanisms of plasticity periods in VPL with adults. We have found two plasticity periods in VPL. The short-term plasticity period may begin during each visual training session and last less than one hour after the end of the session. The long-term plasticity period may last for at least several days, during which a reorganization of visual processing gradually occurs until performance levels for the trained task saturates. Thus, we need to examine the mechanisms of these two periods separately. In Aim 1, we will conduct systematic psychophysical investigations to better understand the two plasticity periods in VPL. We have found that 3-hour monocular deprivation (MD) enhances plasticity of monocular processing possibly by abolishing inter-ocular inhibition, whereas reward priming enhances plasticity of binocular processing in a descending way. We will examine how 3-hour MD and reward priming influence the plasticity and stabilization of these two plasticity periods. In Aim 2, we will examine roles of excitatory and inhibitory processing in the two plasticity periods. The start and end of a visual critical period are associated with changes in the ratio of excitatory to inhibitory signals (E/I ratio). We will address the question of whether and how the two plasticity periods in VPL with adults also relate to E/I ratio changes by means of magnetic resonance spectroscopy. Strong preliminary results have led us to the perspective that the results from Aims 1 and 2 will be consistently and constructively integrated so that functional and neural mechanisms of the two plasticity periods will be better clarified. The results would also be used to develop effective interventions for visual disorders. Although VPL is likely to be associated with changes both within and beyond the visual areas, as our initial approach we will focus on examining visual areas in this proposal.