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

了解引起知觉觉知的神经机制是人类认知神经科学中一项由来已久的基本努力。几十年来，认知神经学家一直试图区分与有意识和无意识加工相关的神经活动模式。回答这个问题可以阐明，基本的意识体验是否与较低级别的感觉系统的活动、较晚发展的额叶皮质较高级别的大脑系统(无论是在进化史还是个体发育学上)有关，还是两者之间的相互作用。这项研究对于理解各种意识障碍也是相关的，比如持续植物人状态或最低意识状态，在这些状态下，个人是没有反应的，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，了解导致人脑有意识体验的神经过程可能有助于开发新的网络结构，旨在更接近地模仿人类的智能。这项拟议的研究的目标是使用各种方法，如脑电图术和功能磁共振成像，确定知觉知觉的神经关联。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。具体地说，他们将研究观察者有意识地感知视觉物品时与没有注意到这些相同物品时神经活动的差异。比较有意识和无意识加工的一个关键问题是，很难将与有意识感知相关的神经事件与与任务表现相关的神经事件(如记忆、决策或言语和手动反应)分开。因此，研究人员将使用新开发的“无报告范式”，其中包括有时可以看到刺激，有时看不到刺激的条件，但观察者不需要报告他们的知觉经验。通过比较观察者报告他们的经验时看得见的和看不见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种领先的意识理论，并确定知觉知觉的最低限度足够的神经关联。这一奖项反映了NSF的法定使命，并通过使用基金会的智力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.