Visual imagery and visual perception induce similar changes in occipital slow waves of sleep

Abstract

Previous studies have shown that regional slow wave activity (SWA) during NREM-sleep is modulated by prior experience and learning. While this effect has been convincingly demonstrated for the sensorimotor domain, attempts to extend these findings to the visual system have provided mixed results. Here we asked whether depriving subjects of external visual stimuli during daytime would lead to regional changes in slow waves during sleep and whether the degree of 'internal visual stimulation' (spontaneous imagery) would influence such changes. In two 8h-long sessions spaced one-week apart, twelve healthy volunteers either were blindfolded while listening to audiobooks or watched movies (control condition), after which their sleep was recorded with high-density EEG. We found that during NREMsleep the number of small, local slow waves in the occipital cortex decreased after listening with blindfolding relative to movie watching in a way that depended on the degree of visual imagery subjects reported during blindfolding: subjects with low visual imagery showed a significant reduction of occipital sleep slow waves, while those who reported a high degree of visual imagery did not. We also found a positive relationship between the reliance on visual imagery during blindfolding and audiobook listening and the degree of correlation in sleep SWA between visual areas and language-related areas. These preliminary results demonstrate that short-term alterations in visual experience may trigger slow wave changes in cortical visual areas. Furthermore, they suggest that plasticity-related EEG changes during sleep may reflect externally induced ('bottom-up') visual experiences, as well as internally generated ('top-down') processes.

Regional Delta Waves In Human Rapid Eye Movement Sleep

“…Because wake data were not available for the above subjects, specific analyses aimed at comparing sleep-and wake-related brain activity (see below) were performed in a different sample of 12 healthy adult individuals (age 25.5 Ϯ 3.7, 6 females) who underwent overnight hd-EEG sleep recordings after having spent 8 h in the sleep laboratory while watching movies (analyses of wake and NREM sleep data from these subjects has been reported previously (Bernardi et al, 2019). These recordings were performed at the Lausanne University Hospital under a research protocol approved by the local ethical committee.…”

Integrity of Corpus Callosum Is Essential for the Cross-Hemispheric Propagation of Sleep Slow Waves: A High-Density EEG Study in Split-Brain Patients

“…Tables 1 and 2 report demographic and clinical characteristics for all patients. An additional control group of 24 healthy adult volunteers (i.e., HSs; age range, 20–47 years; 13 females) was studied with the same hd-EEG recording system at the Lausanne University Hospital (Lausanne, Switzerland; analyses of NREM sleep data from these subjects, not involving the study of inter-hemispheric slow-wave propagation, have been reported in previous work; Siclari et al, 2018 ; Bernardi et al, 2019a , b ). Before their inclusion in the study, HS group individuals underwent a clinical interview to exclude a history of sleep, medical, and psychiatric disorders.…”

Emotion suppression failures are associated with local increases in sleep-like activity

“…Indeed, seminal work in rats demonstrated that locally synchronized neuronal off-periods similar to those underlying the generation of sleep slow waves (0.5-4 Hz) occur more frequently as a function of time spent awake (Vyazovskiy et al, 2011). Studies in humans also revealed that such increases are of greater magnitude in brain areas that are more intensively 'used' during the waking period (Hung et al, 2013;Quercia et al, 2018;Bernardi et al, 2019;Petit et al, 2019). Interestingly, the occurrence of sleep-like events in brain areas related to the execution of ongoing activities has been shown to potentially determine temporary behavioral impairments in a variety of different tasks, including impulse control, visuo-motor coordination and stimulus categorization (Bernardi et al, 2015;Nir et al, 2017).…”