The role of dynamical criticality in human perception

动态临界性在人类感知中的作用

基本信息

批准号：
10649410
负责人：
TIMOTHY H LUCAS
金额：
$ 55.7万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-15 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10649410
关键词：
Address Affect Anesthesia procedures Anesthesiology Arousal Auditory Auditory Threshold Awareness Bayesian Modeling Binding Brain Brain Injuries Complex Conscious Data Data Set Dedications Detection Diagnosis Drowsiness Electric Stimulation Electrical Stimulation of the Brain Electrocorticogram Electrodes Epilepsy Frequencies General Anesthesia General anesthetic drugs High Frequency Oscillation Human Implant Intuition Ketamine Link Masks Mathematics Measures Monitor Neurology Neurons Neurosciences Noise Operative Surgical Procedures Patients Pattern Perception Phase Physiologic pulse Polysomnography Probability Property Propofol Psychometrics Psychophysics Research Role Sedation procedure Sensory Signal Transduction Sleep Sleep Deprivation Sleep Stages Sleep Wake Cycle Slow-Wave Sleep Speech Stimulus Techniques Technology Testing Time Titrations Training Unconscious State Wakefulness auditory stimulus awake clinically significant dynamic system human subject inattention insight millisecond neurophysiology nonhuman primate novel pharmacologic predicting response response sensory stimulus sound spatiotemporal theories

项目摘要

PROJECT SUMMARY Brain activity never ceases. When we are asleep, inattentive, or even under general anesthesia, networks of interconnected neurons in the human brain continue to spontaneously generate complex activity patterns. Sensory stimuli perturb this ongoing spontaneous neuronal activity. In order to be consciously detected, the effect of this perturbation needs to be large enough so as to engage thousands of neurons and persist for at least several hundred milliseconds. When we are awake and attentive, the smallest stimuli are sufficient to elicit a large perturbation. Under general anesthesia, however, even the most noxious stimuli do not reach the threshold for conscious perception. Here we address a fundamental question: why are sensory stimuli able to perturb neuronal activity in some states but not in others? We hypothesize that the ability of the sensory stimuli to perturb neuronal activity is related to the property of dynamical systems termed stability. If neuronal dynamics were unstable, the effect of any perturbation would grow over time without bounds and engage ever increasing number of neurons. Conversely, if the dynamics were too stable, then all perturbations will quickly dampen down and fail to reach threshold of perception. Thus, we hypothesize that conscious perception is most likely to occur when the neuronal dynamics are poised precisely between the stable and unstable regimes. We refer to this point as critical. To test the criticality hypothesis, we developed novel mathematical techniques and applied them to neurophysiological recordings in humans and in nonhuman primates. These preliminary findings strongly support the hypothesis. In the proposed project, we will rigorously test the criticality hypothesis using electrocorticography (ECoG) in human subjects implanted with electrodes for epilepsy localization. We will determine how the stability of spontaneous activity varies as a function of sleep and wake, attentiveness and drowsiness, as well as sedation and general anesthesia. We will validate the criticality hypothesis and our ability to estimate stability of neuronal activity by predicting responses to electrical brain stimulation. Using an auditory masked speech detection task, we will also determine whether stability of neuronal dynamics can be used to predict whether a natural stimulus presented at perceptual threshold will be consciously detected. While many other measures of neuronal activity have been previously associated with changes in arousal and perception, at present, it is not possible to apply the existing measures to unequivocally distinguish between activity in the conscious and unconscious brain. Hence, validating this criticality hypothesis would be a major advance. In addition to addressing a fundamental issue in neuroscience, finding an objective and quantifiable measure of sensory responsiveness has profound clinical significance in neurology and in anesthesiology where diagnoses of covert awareness under anesthesia or after brain injury cannot be made reliably with existing technology.

项目摘要大脑活动永远不会停止。当我们睡着，不专心，甚至在全身麻醉下，人脑中的互连神经元继续自发地产生复杂的活动模式。感觉刺激扰动这种正在进行的自发神经元活性。为了有意识地检测到这种扰动的效果必须足够大，以使成千上万的神经元并持续存在至少几百毫秒。当我们醒着和专心时，最小的刺激就足够了引起大型扰动。但是，在全身麻醉下，即使是最有害的刺激也没有达到有意识的阈值。在这里，我们解决了一个基本问题：为什么感官刺激能够在某些州的神经元活动，但在另一些州却没有？我们假设感觉刺激的能力扰动神经元活动与称为稳定性的动态系统的特性有关。如果神经元动态不稳定，任何扰动的效果都会随着时间的流逝而增长而没有界限并参与神经元数量的增加。相反，如果动态太稳定，那么所有扰动都会迅速抑制，无法达到感知的阈值。因此，我们假设有意识的感知是当神经元动力学精确地在稳定和不稳定之间固定时，最有可能发生政权。我们将这一点称为关键。为了检验关键性假设，我们开发了新颖的数学技术并将其应用于人类和非人类灵长类动物中的神经生理记录。这些初步发现强烈支持该假设。在拟议的项目中，我们将严格测试使用皮质摄影（ECOG）的临界性假设在植入电极的人类受试者中癫痫定位。我们将确定自发活动的稳定性如何随着睡眠而变化唤醒，注意力和嗜睡，镇静和全身麻醉。我们将验证关键性假设以及我们通过预测对电的反应来估计神经元活动稳定性的能力大脑刺激。使用听觉蒙版的语音检测任务，我们还将确定是否稳定神经元动力学可用于预测感知阈值的自然刺激是否会有意识地检测到。虽然以前与唤醒和感知的变化，目前不可能将现有措施应用于明确区分有意识和无意识的大脑的活动。因此，对此进行了验证批判性假设将是一个重大进步。除了解决神经科学中的基本问题外，找到一种客观和可量化的感觉响应能力的衡量标准在神经病学和麻醉学中的诊断在麻醉下或脑损伤后诊断为秘密意识现有技术无法可靠地制造。