Collaborative Research: RUI: Isolating neural mechanisms of perceptual awareness from post-perceptual processes

理解产生知觉的神经机制是人类认知神经科学中一项长期而基本的研究。几十年来，认知神经科学家一直试图区分与有意识和无意识处理相关的神经活动模式。回答这个问题可以揭示基本的意识体验是否与较低层次感觉系统的活动有关，是否与较晚发展的额叶皮层高级大脑系统的活动有关（在系统发育和个体发育中），或者两者之间的相互作用有关。这项研究也与理解各种意识障碍有关，比如持续性植物人状态或最低意识状态，在这些状态下，个体没有反应，这些发现可能是构建计算机算法的第一步，可以表明意识状态的存在。最后，随着机器学习和神经网络的采用，理解导致人类大脑有意识经验的神经过程可能有助于开发旨在更接近模拟人类智能的新网络架构。本研究的目的是利用脑电图和功能性磁共振成像等多种方法来识别感知意识的神经相关因素。为了研究这个问题，研究人员将比较清醒的人类观察者大脑中有意识和无意识的处理过程。具体来说，他们将研究当观察者有意识地感知视觉物品时，与不被注意到这些物品时，神经活动的差异。比较有意识和无意识处理的一个关键问题是，很难将与有意识感知相关的神经事件与与任务表现（如记忆、决策或口头和手动反应）相关的神经事件分开。因此，研究人员将使用新开发的“无报告范式”，其中包括刺激有时被看到，有时不被看到，但观察者不需要报告他们的感知体验的条件。通过比较当观察者报告他们的经历和不报告时看到的和没有看到的刺激的不同神经活动，研究人员将有一个独特的机会来测试几个领先的意识理论，并确定知觉意识的最低限度的神经关联。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding the neural mechanisms that give rise to perceptual awareness is a long-standing and fundamental endeavor in human cognitive neuroscience. For decades, cognitive neuroscientists have tried distinguishing between neural activity patterns associated with conscious and unconscious processing. Answering this question can shed light on whether the fundamental conscious experience is linked to activity in lower-level sensory systems, higher-level brain systems in frontal cortex that developed later (in both phylogeny and ontogeny), or interactions between the two. This investigation is also relevant for understanding various disorders of consciousness such as persistent vegetative state or minimally conscious state, in which individuals are non-responsive, and where such findings could be a first step towards construction of computer algorithms that could indicate the presence of conscious states. Finally, with the adoption of machine learning and neural networks, understanding the neural processes that lead to conscious experience in the human brain could be useful in developing new network architectures designed to more closely mimic human intelligence. The goal of the proposed research is to identify neural correlates of perceptual awareness using a variety of methods such as electroencephalography and functional magnetic resonance imaging. To examine this issue, the researchers will compare conscious versus unconscious processing in the brains of awake human observers. Specifically, they will investigate the differences in neural activity when observers consciously perceive visual items compared to when those same items go unnoticed. A critical problem in comparing conscious versus unconscious processing is that it is difficult to separate the neural events associated with conscious perception from the neural events associated with task performance such as memory, decision-making, or verbal and manual responses. Therefore, the researchers will use newly developed "no-report paradigms" that include conditions in which stimuli are sometimes seen and sometimes unseen, but observers are not required to report their perceptual experience. By comparing differential neural activity for seen versus unseen stimuli when observers report their experience versus when they do not, the researchers will have a unique opportunity to test several leading theories of consciousness and to identify minimally sufficient neural correlates of perceptual awareness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.