Evoked potentials as a tool for the investigation of human sleep

Bastuji, Hélène

doi:10.1016/s1087-0792(99)90012-6

Cited by 128 publications

(83 citation statements)

References 77 publications

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“…Importantly, we do not claim that NREM sleep is associated with a total obliteration of conscious mental representations. The brain remains responsive to external stimuli during NREM sleep (12,13) and dreams have been reported after NREM sleep awakenings (14). However, the aim of the current paper was not to characterize the neural correlates of these mental representations but rather to contrast brain function during normal wakefulness to that observed during a state of impoverished conscious content such as NREM sleep.…”

Section: Discussionmentioning

confidence: 97%

Hierarchical clustering of brain activity during human nonrapid eye movement sleep

Boly

Perlbarg

Marrelec

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

177

199

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Consciousness is reduced during nonrapid eye movement (NREM) sleep due to changes in brain function that are still poorly understood. Here, we tested the hypothesis that impaired consciousness during NREM sleep is associated with an increased modularity of brain activity. Cerebral connectivity was quantified in restingstate functional magnetic resonance imaging times series acquired in 13 healthy volunteers during wakefulness and NREM sleep. The analysis revealed a modification of the hierarchical organization of large-scale networks into smaller independent modules during NREM sleep, independently from EEG markers of the slow oscillation. Such modifications in brain connectivity, possibly driven by sleep ultraslow oscillations, could hinder the brain's ability to integrate information and account for decreased consciousness during NREM sleep.complexity | integration D uring nonrapid eye movement (NREM) sleep, we are less aware of ourselves and our environment and, if we awaken, are less able to recollect any mental representation than during full-blown wakefulness (1). The mechanisms underpinning the reduction in conscious content during NREM sleep are still uncertain. Consciousness has been associated with the ability of a system to integrate information (2), which could be altered during NREM sleep. Here, in contrast to previous work (3, 4), we quantified changes in information integration from wakefulness to NREM sleep in large-scale brain networks and computed both their total integration and their degree of functional clustering. Functional clustering estimates how integration is hierarchically organized within and across the constituent parts of a system. It has been proposed as an empirically tractable measure for complexity of brain integration (5), which is considered a better estimate of the capacity to integrate information than total integration (6).We assessed brain functional connectivity on functional MRI (fMRI) data, which reflect the slow dynamics of local field potentials rather than instantaneous neural activities (7). Data were collected in a single nocturnal session in 13 participants who maintained periods of steady NREM sleep. At awakening, none of the subjects could recall any mental conscious content since sleep onset. From this dataset, we extracted for each subject two subsets of consecutive volumes recorded, respectively, during wakefulness and NREM sleep. Six spatially independent patterns, which we refer to as networks (Fig. 1A), were identified at the group level on wakefulness data, using a data-driven method (independent component analysis). These networks [visual (VIS), motor (MOT), default mode (DM), dorsal attentional (dATT), executive control (EC), and salience (SAL)] were previously identified in many studies investigating restingstate fMRI correlations in the literature (8-10). Network composition was very similar in data obtained during NREM sleep compared with wakefulness, in terms of within-networks areas distribution and Euclidian distance between networks (SI Results ...

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Section: Discussionmentioning

confidence: 97%

Hierarchical clustering of brain activity during human nonrapid eye movement sleep

Boly

Perlbarg

Marrelec

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

177

199

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“…Such an unpredictable signal will be considered as a highly complex signal. Previous studies have shown that LZc accurately tracks the level of consciousness in patients, healthy subjects under anesthesia and during sleep (Casali et al, 2013;Abásolo et al, 2015;Schartner et al, 2015). For example, when the EEG signal is populated by high-amplitude synchronous slow waves as in deep NREM sleep, the signal becomes more predictable and the associated LZc value decreases compared with wakefulness or REM sleep (see Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Even when sleep is preserved, familiar stimuli exhibit different brain responses (Perrin et al, 1999). In recent years, several studies have shown that external information processing may extend far beyond automatic operations: from the detection of semantic incongruity (Bastuji and García-Larrea, 1999;Ibáñez et al, 2006) or the violation of simple rules (Ruby et al, 2008;Strauss et al, 2015) to the formation of new associations (Arzi et al, 2012;de Lavilléon et al, 2015). The cognitive processes involved during sleep therefore appear more elaborated than previously thought.…”

Section: Introductionmentioning

confidence: 99%

“…K-complexes have sometimes been related to arousal systems (Siclari et al, 2014) providing windows of wakefulness to sleepers (Destexhe et al, 2007). Conversely, they have also been described as local down states (Cash et al, 2009) entailing large-scale neuronal silencing (Vyazovskiy and Harris, 2013) and protecting sleep against external stimulations (Wauquier et al, 1995;Bastien et al, 2000). This tendency neurons have to alternate between periods of activations (up states) and silencing (down states) (Sanchez-Vives and McCormick, 2000) is termed "neuronal bistability" and has been proposed as a mechanism limiting sensory processing at the cortical level (Tononi and Massimini, 2008;Pigorini et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Neural Markers of Responsiveness to the Environment in Human Sleep

et al. 2016

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Sleep is characterized by a loss of behavioral responsiveness. However, recent research has shown that the sleeping brain is not completely disconnected from its environment. How neural activity constrains the ability to process sensory information while asleep is yet unclear. Here, we instructed human volunteers to classify words with lateralized hand responses while falling asleep. Using an electroencephalographic (EEG) marker of motor preparation, we show how responsiveness is modulated across sleep. These modulations are tracked using classic event-related potential analyses complemented by Lempel-Ziv complexity (LZc), a measure shown to track arousal in sleep and anesthesia. Neural activity related to the semantic content of stimuli was conserved in light non-rapid eye movement (NREM) sleep. However, these processes were suppressed in deep NREM sleep and, importantly, also in REM sleep, despite the recovery of wake-like neural activity in the latter. In NREM sleep, sensory activations were counterbalanced by evoked down states, which, when present, blocked further processing of external information. In addition, responsiveness markers correlated positively with baseline complexity, which could be related to modulation in sleep depth. In REM sleep, however, this relationship was reversed. We therefore propose that, in REM sleep, endogenously generated processes compete with the processing of external input. Sleep can thus be seen as a self-regulated process in which external information can be processed in lighter stages but suppressed in deeper stages. Last, our results suggest drastically different gating mechanisms in NREM and REM sleep.

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“…Çalışmada seyrek ve sık uyaranlara karşı oluşan P200 yanıtının genliğinde anlamlı farklılık bulunmamıştır. Olay ilişkili potansiyel çalışmalarında Evre 1, Evre 2 ve yavaş dalga uykusunda iki negatif bileşen olan N300 ve N550 bileşenleri kayıt edilmiştir (21). N300 yanıtı uyaranın anlamsal içeriği ile ilişkili bulunurken, N550 yanıtı ise uyaranın fiziksel özelliği ile ilişkili bulunmuştur (22).…”

Section: Discussionunclassified