Motion and Form Processing in Extrastriate Visual Cortex

描述(申请人提供)：感觉经验的联想回忆是知觉的重要组成部分。通过一个无处不在的自动过程，从感觉外围上升的不完整、嘈杂和模糊的信号被联想记忆充实和消除歧义。与这一观点一致的是，人类的大脑功能成像研究表明，视觉图像记忆的回忆与处理传入视觉刺激的相同皮质区域的自上而下激活相关。运用神经生理学和行为学相结合的方法，我们最近开始在灵长类视觉皮质的细胞水平上探索自上而下的联想回忆信号，并将这些细胞信号与视觉意象和知觉联系起来。最重要的是，我们在大脑皮层视觉区域MT中发现了高度特异的联想回忆信号，该区域在视觉运动处理中起着核心作用。我们的发现为详细定量研究图像记忆回忆的功能和神经机制提供了一种新的模型系统。我们提出了一系列神经生理和行为实验，旨在提高对自上而下回忆信号的来源和可塑性、它们在整个视觉皮质中的分布以及回忆和自下而上视觉感觉之间的相互作用的理解。通过这些手段，我们希望揭示记忆、意象和知觉之间的动态相互作用。该项目的长期目标是促进对感知和认知的生物基础的理解。对视觉皮质正常功能的详细了解应提供对构成视觉记忆、想象、做梦和知觉障碍(如幻觉)表现的神经事件的洞察。这些信息最终将有助于治疗和预防视觉感知和记忆的神经和神经精神障碍。这些目标与为视力和记忆障碍者开发和使用假体、行为和药物疗法有关。

DESCRIPTION (provided by applicant): Associative recall of sensory experiences is part-and-parcel of perception. Through a ubiquitous and automatic process, incomplete, noisy and ambiguous signals ascending from the sensory periphery are fleshed-out and disambiguated by associative memories. Consistent with this view, functional brain imaging studies in humans have shown that recall of visual pictorial memories is correlated with top-down activation of the same cortical areas that process incoming visual stimuli. Using a combination of neurophysiological and behavioral approaches, we have recently begun to explore top-down associative recall signals at the cellular level in primate visual cortex, and to relate these cellular signals to visual imagery and perception. Most importantly, we have discovered highly specific associative recall signals in cortical visual area MT, an area that plays a central role in visual motion processing. Our findings suggest a novel model system for detailed quantitative investigation of the functions and neuronal mechanisms of pictorial memory recall. We have proposed a series of neurophysiological and behavioral experiments designed to improve understanding of the source and plasticity of top-down recall signals, their distribution throughout visual cortex, and the interactions between recall and bottom-up visual sensations. By these means we hope to reveal the dynamic interplay between memory, imagery and perception. The long-term goal of this project is to contribute to the understanding of biological substrates of perception and cognition. Detailed knowledge of the normal functions of visual cortex shall provide insights into the neural events that underlie visual memory, imagery, dreaming and manifestations of perceptual disorders, such as hallucinations. Such information will ultimately aid in the treatment and prevention of neurological and neuropsychiatric disorders of visual perception and memory. These aims are pertinent to the development and use of prosthetic, behavioral, and pharmacological therapies for the visually and mnemonically handicapped.