Towards the neuronal correlates of visual awareness

描述(由申请人提供) 摘要：大脑，一个由神经元和突触组成的物理系统，可以产生似乎是所有东西中最不重要的物理属性：意识。这种转变是如何发生的，一直是几代临床医生和科学家关注的问题。在过去的几十年里，神经科学的进步使得研究负责意识的神经回路成为可能。这一建议关注意识体验的一个特殊方面：构成视觉感知的神经机制和回路。我们建议使用神经生理学、心理物理学和电刺激相结合的方法来研究视觉意识。我们利用一个难得的机会，在受试者报告他们的感知时，使用高空间和时间分辨率(神经元和毫秒)的神经生理学来检查人类枕叶和颞叶的活动。我们提出了两个将视觉感知与视觉输入分离的实验：双目竞争和运动诱导失明。在这两种情况下，尽管有持续的视觉输入，感知还是会发生变化。我们研究了沿腹侧视觉皮质(从初级视觉皮质到下颞叶皮质)神经元的反应在哪里、何时以及如何随着知觉的改变而改变其活动模式。此外，我们还询问这些神经生理反应是否足以通过电刺激局部回路来引起知觉。意识加工的障碍可能是毁灭性的，是癫痫、植物昏迷、精神分裂症和自闭症等看似多样的疾病的核心。加深我们对视觉背景下大脑和思维之间的联系的理解，将为解决意识的其他方面铺平道路，并可能对改变我们思考和解决这些挑战性障碍的方式产生深远的影响。 与公共健康相关：大脑，一个由神经元和突触组成的物理系统，可以产生似乎是所有物质中最不重要的属性：意识。理解产生感知、感觉和思想的神经机制可以说是当今最大的科学挑战之一。在描述神经元活动和知觉之间的联系方面的进展将在我们的社会中产生深远的影响，特别是在临床应用中。有多种临床情况涉及意识状态的改变，包括癫痫、自闭症、植物昏迷和精神分裂症等。患有这些疾病的人可以活几年，但他们的生活质量(以及他们周围朋友和家人的生活质量)可能会受到严重损害。这些情况导致了社会和学习方面的挑战，这些挑战往往会影响到患病的人的一生。在这些条件的交汇处，存在着表达有意识的思想和感知有意识的感觉的根本挑战。在所有这些情况下，意识都可以通过行为来定义。然而，大脑活动什么、何时以及如何导致有意识的体验还不清楚。这里我们特别关注视觉感知，因为它更容易操纵视觉输入，我们更了解潜在的电路，我们可以相当准确地定量评估感知。我们的研究工作将调查神经元的类型、位置、电路、相互作用和引起视觉感知的动力学。

DESCRIPTION (Provided by the applicant) Abstract: The brain, a physical system composed of neurons and synapses, can give rise to what seems to be the least physical property of all: consciousness. How this transformation takes place has preoccupied generations of clinicians and scientists. Advances in Neuroscience over the last several decades make it possible to enquire into the neural circuits responsible for consciousness. This proposal focuses on one particular aspect of conscious experience: the neuronal mechanisms and circuits that underlie visual awareness. We propose to study visual awareness using a combination of neurophysiology, psychophysics and electrical stimulation. We take advantage of a rare opportunity to examine activity in the human occipital and temporal lobes using neurophysiology at high spatial and temporal resolution (neurons and milliseconds) while subjects report their perceptions. We propose two experiments where visual perception is dissociated from the visual input: binocular rivalry and motion-induced blindness. In both cases, perception changes in spite of a constant visual input. We investigate where, when and how neuronal responses along ventral visual cortex (from primary visual cortex to inferior temporal cortex) change their activity patterns with the perceptual alternations. Furthermore, we ask whether those neurophysiological responses are sufficient to elicit perception by electrically stimulating local circuits. Impairments in conscious processing can be devastating and are at the core of seemingly diverse conditions as epilepsy, vegetative coma, schizophrenia and autism. Furthering our understanding of the link between brains and minds in the context of vision will pave the way for addressing other aspects of consciousness and may have profound implications in changing how we think about and address these challenging disorders. Public Health Relevance: The brain, a physical system composed of neurons and synapses, can give rise to what seems to be the least physical property of all: consciousness. Understanding the neuronal mechanisms that give rise to perceptions, feelings and thoughts is arguably one of the biggest scientific challenges today. Advances towards describing the link between neuronal activity and perception will have a profound impact in our society, particularly in clinical applications. There are multiple clinical conditions that involve altered states of consciousness including epilepsy, autism, vegetative coma and schizophrenia among others. Subjects afflicted by these conditions can live for years, yet their quality of life (and that of their surrounding friends and families) can be severely impaired. These conditions lead to social and learning challenges that often impact the afflicted individuals for life. At the intersection of these conditions resides a fundamental challenge to express conscious thoughts and to perceive conscious feelings. In all these cases, consciousness can be behaviorally defined. However, what, when and how brain activity leads to conscious experience is not understood. Here we specifically focus on visual awareness because it is easier to manipulate the visual input, we understand more about the underlying circuitry and we can quantitatively assess perception rather accurately. Our research efforts will investigate the types of neurons, locations, circuits, interactions and dynamics that give rise to visual perception.