fMRI lag structure during waking up from early sleep stages.
Cortex; a journal devoted to the study of the nervous system and behavior – September 01, 2021
Source: PubMed
Summary
Suddenly waking up from early sleep stages involves a fascinating two-stage brain process. Analyzing data from 20 participants, the transition begins with subcortical and sensorimotor areas activating first, followed by rapid whole-brain engagement, where frontal regions activate slightly later. Conversely, a slower phase may occur, reversing this pattern as cortical regions engage before subcortical structures. This sequence highlights the crucial role of subcortical structures in initiating and maintaining conscious states, shedding light on the complexities of consciousness and brain function during awakening.
Abstract
The brain mechanisms by which we transition from sleep to a conscious state remain largely unknown in humans, partly because of methodological challenges. Here we study a pre-existing dataset of waking up participants originally designed for a study of dreaming (Horikawa, Tamaki, Miyawaki, & Kamitani, 2013) and suggest that suddenly awakening from early sleep stages results from a two-stage process that involves a sequence of cortical and subcortical brain activity. First, subcortical and sensorimotor structures seem to be recruited before most cortical regions, followed by fast, ignition-like whole-brain activation-with frontal regions engaging a little after the rest of the brain. Second, a comparably slower and possibly mirror-reversed stage might take place, with cortical regions activating before subcortical structures and the cerebellum. This pattern of activation points to a key role of subcortical structures for the initiation and maintenance of conscious states.