Reduced neural feedback signaling despite robust neuron and gamma auditory responses during human sleep

We recorded single-unit spiking (713 clusters), microwire LFPs and iEEG from 13 patients implanted with depth electrodes while playing sounds (click-trains, words, music) during wakefulness and sleep, studying auditory responses (observed mainly in lateral temporal lobe). Amplitude of spike and gamma responses was similar in wake and NREM sleep, with modest or no attenuation in […]

Propofol Anesthesia Concentration Rather Than Abrupt Behavioral Unresponsiveness Linearly Degrades Responses in the Rat Primary Auditory Cortex

Loss of consciousness happens abruptly, but does the neuronal activity in our brains also change suddenly? Here we gradually deepen anaesthesia in rats whilst playing aounds and recording how their neurons fire in the auditory cortex. We found a range of different changes with anaesthesia, but all of them changed gradually with increased anaesthesia, and […]

Noradrenaline Modulates Visual Perceptionand Late Visually Evoked Activity

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 […]

Attenuated Fast Steady-State Visual Evoked Potentials During Human Sleep

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 […]

Selective neuronal lapses precede human cognitive lapses following sleep deprivation

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 […]