The neural basis of visual priming

人类大脑随着经验不断变化和更新的能力是区别于人工构造设备的基本特性之一。人类大脑中经验依赖变化的一种表现是视觉启动，在这种情况下，与在新刺激下的表现相比，在重复物体上的表现会得到改善（反应更快、更准确）。尽管在视觉启动的行为方面有丰富的知识，但对潜在的神经机制知之甚少。脑成像技术的最新进展使Kalanit Grill-Spector博士能够检查刺激重复时大脑发生的变化。例如，她和她的同事发现，重复物体图像会降低人类视觉皮层中物体选择区域的大脑活动。然而，为什么皮层活动的减少会与行为表现的改善有关，这是违反直觉的。在国家科学基金会的资助下，格里尔-斯佩克特博士的项目目标是了解视觉启动背后的神经机制，以及这些机制如何在人类大脑中客体选择区域的皮层活动中产生变化。这些实验旨在区分解释视觉启动的不同理论，并排除非特定过程，如整体注意力水平的变化。为此，格里尔-斯佩克特博士将结合脑成像实验和行为测量。通过操纵重复参数、自上而下的注意力和刺激强度，并测量这些因素对行为和大脑激活的影响，她将确定哪种机制更相关。该项目的研究结果将对理解视觉系统中经验依赖变化的神经基础至关重要，并将对感知学习、内隐记忆和视觉认知领域产生重大影响。这些实验将对理解一个基本的和被广泛研究的认知过程的生理基础有重要的贡献：视觉启动。阐明视觉启动的认知和神经基础将影响对高级视觉区域的感知学习和物体表征的可塑性的理解，进而影响从内隐记忆的临床方面到物体识别的人工智能模型的一系列领域。例如，更好地了解感知学习或技能学习的神经基础，将有助于为中风或其他局部大脑感觉皮质区域损伤的患者提供更好的康复方案。此外，这项工作将为视觉记忆相关的神经过程提供实质性的新见解，这对获得新的物体识别技能具有重要意义。这类技能是许多形式的科学和医学培训（例如，理解放射照片或学习从视觉上区分染色体）的一个重要方面。总之，通过提供对神经可塑性的更深入的理解，这项工作将告知我们对视觉系统中经验依赖的变化以及广泛的学习和记忆现象的理解。

The ability of the human brain to continuously change and update with experience is one of the fundamental properties that distinguishes it from artificially constructed devices. One manifestation of experience-dependent changes in the human brain is visual priming, in which performance on repeated objects is improved compared to performance on new stimuli (responses are both faster and more accurate). Despite the rich knowledge on the behavioral aspects of visual priming, much less is known about the underlying neural mechanisms. Recent advances in brain imaging have allowed Dr. Kalanit Grill-Spector to examine the brain changes that occur with stimulus repetition. For example, she and her colleagues have found that repeating object images reduces the brain activity in object-selective areas in the human visual cortex. However, it is counterintuitive why reduced cortical activity would be associated with improved behavioral performance? With NSF funding, the goal of Dr. Grill-Spector's project is to understand the neural mechanisms underlying visual priming and to understand how these mechanisms produce changes in cortical activity in object-selective areas in the human brain. These experiments are designed to distinguish between alternative theories explaining visual priming and to rule out non-specific processes, such as changes in the overall attention level. To do so, Dr. Grill-Spector will combine brain imaging experiments and behavioral measurements. By manipulating repetition parameters, top-down attention and stimulus strength, and measuring the effect of these factors on both behavior and brain activation, she will determine which mechanism is more relevant. The results of this project will be critical for understanding the neural basis of experience-dependent changes in the visual system and will have a large impact on the fields of perceptual learning, implicit memory and visual cognition. These experiments will have an important contribution in understanding the physiological basis of a fundamental and intensively studied cognitive process: visual priming. Elucidating the cognitive and neural bases of visual priming will impact understanding of perceptual learning and plasticity of object representations in high-level visual areas, which in turn will affect a range of fields from clinical aspects of implicit memory to AI models of object recognition. For example, better understanding of the neural basis of perceptual learning or skill learning will facilitate better rehabilitation programs for patients who experienced strokes or other localized brain damage to sensory cortical areas. Furthermore, the proposed work will provide substantial novel insights into the neural processes associated with visual memory, which has important implications for the acquisition of novel object recognition skills. This type of skill is an important aspect of many forms of scientific and medical training (e.g., understanding radiological photos or learning to visually distinguish between chromosomes). In sum, by providing a greater understanding of neural plasticity, this work will inform our understanding of experience-dependent changes in the visual system as well as a wide range of learning and memory phenomena.