Brain Mechanisms of Conscious Awareness: Detect, Pulse, Switch, and Wave
Year: 2021
Type: article
Abstract: Consciousness is a fascinating field of neuroscience research where questions often outnumber the answers. We advocate an open and optimistic approach where converging mechanisms in neuroscience may eventually provide a satisfactory understanding of consciousness. We first review several characteristics of conscious neural activity, including the involvement of dedicated systems for content and levels of consciousness, the distinction and overlap of mechanisms contributing to conscious states and conscious awareness of transient events, nonlinear transitions and involvement of large-scale networks, and finally the temporal nexus where conscious awareness of discrete events occurs when mechanisms of attention and memory meet. These considerations and recent new experimental findings lead us to propose an inclusive hypothesis involving four phases initiated shortly after an external sensory stimulus: (1) Detect-primary and higher cortical and subcortical circuits detect the stimulus and select it for conscious perception. (2) Pulse-a transient and massive neuromodulatory surge in subcortical-cortical arousal and salience networks amplifies signals enabling conscious perception to proceed. (3) Switch-networks that may interfere with conscious processing are switched off. (4) Wave-sequential processing through hierarchical lower to higher cortical regions produces a fully formed percept, encoded in frontoparietal working memory and medial temporal episodic memory systems for subsequent report of experience. The framework hypothesized here is intended to be nonexclusive and encourages the addition of other mechanisms with further progress. Ultimately, just as many mechanisms in biology together distinguish living from nonliving things, many mechanisms in neuroscience synergistically may separate conscious from nonconscious neural activity.
Source: The Neuroscientist
Author: Hal Blumenfeld
Institution: Yale University
Language: English
Subfield: Experimental and Cognitive Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
Awards: Thalamic stimulation to prevent impaired consciousness in epilepsy, Network mechanisms of seizure-induced cardiorespiratory impairment, Neuroimaging, neuronal firing and behavior in spike-wave seizures, Functional Neuroimaging in Childhood Absence Epilepsy, Thalamic stimulation to prevent impaired consciousness in epilepsy, Remote effects of focal hippocampal seizures on neocortical function, Yale Clinical and Translational Science Award, G96299199
OpenAlex ID: W3206051771