Focal temporal lobe seizures in humans often cause loss of consciousness accompanied by cortical slow waves similar to deep sleep. Previous rat studies under anesthesia suggested that reduced subcortical arousal depresses cortical function, but could not link conscious behavior to physiology. In an awake mouse model, electrically induced hippocampal seizures impaired behavioral responses to sounds, triggered cortical slow waves, and reduced mean high-frequency cortical activity. Behavioral responses depended on cortical acetylcholine release at two timescales: slow state-related decreases correlated with overall impairment, while fast phasic release corresponded to variable spared or impaired responses per stimulus. These results establish a strong link between decreased cortical arousal and impaired consciousness during focal seizures.
Awareness of action (AoA)—the conscious awareness of one's own actions—is crucial for daily life, yet its neural basis is poorly understood. By developing a game where participants repeatedly made nearly identical moves while distracted, then reported awareness or unawareness of those moves, the authors compared neural activity between aware and unaware actions. On short timescales, aware actions showed larger neurophysiological signals both before and after movement, including volitional and perceptual event-related potentials, frontal midline theta, alpha/beta desynchronization, and increased blink rates. On longer timescales, a novel positive event-related potential preceded only unaware moves, and behavioral and pupillometric evidence indicated decreased attention and arousal concurrent with AoA loss. Three synergistic neural mechanisms were identified: long-term increases in arousal/attentional state, increased motor volitional signals, and increased sensory perceptual signals.