An identical sensory stimulus may or may not be incorporated into perceptual experience, depending on the behavioral and cognitive state of the organism. What determines whether a sensory stimulus will be perceived? Here we tested whether noradrenaline signaling may play a key role. We pharmacologically down- and upregulated noradrenaline signaling in healthy volunteers using clonidine […]
Despite the persistence of some sensory processing during sleep, it is unclear whether high-level cognitive processes such as speech parsing are also preserved. We used a novel Concurrent Hierarchical Tracking (CHT) approach for studying the depth of speech processing across wakefulness and sleep while tracking neuronal activity with EEG. We found that responses to the […]
We studied how natural loss of consciousness during sleep affects visual processing using high density scalp EEG in healthy human participants. We found attenuated fast frequency following responses in the visual cortex in sleep (N/REM) compared to wakefulness while slow and onset responses were stronger in sleep. These results supports the view that during sleep […]
Sleep deprivation has widespread health effects, including increased risk of hypertension, diabetes, obesity, heart attack, and stroke. In addition, it leads to car accidents and medical errors. During sleep deprivation, homeostatic and circadian processes interact to build up sleep pressure, which results in slow behavioral performance (cognitive lapses). Here we used intracranial electrodes to record […]
A long held hypothesis postulated that brain waves called sleep spindles inhibit transmission of information from thalamus to cortex. In here we disputed this claim by showing neurons in the primary auditory cortex (first station after the thalamus) respond similarly to sounds, regardless of the occurrence of sleep spindles.
Sleep entails a disconnection from the external environment. By and large, sensory stimuli do not trigger behavioral responses and are not consciously perceived as they usually are in wakefulness. Traditionally, sleep disconnection was ascribed to a thalamic “gate,” which would prevent signal propagation along ascending sensory pathways to primary cortical areas. Here, we compared single-unit […]
