Carolin Reichert

• PhD
• Universitäre Psychiatrische Kliniken Basel

Fixed sleep schedules with an 8 h time in bed (TIB) are used to ensure participants are well-rested before laboratory studies. However, such schedules may lead to cumulative excess wakefulness in young individuals. Effects on older individuals are unknown. We combine modelling and experimental data to quantify the effects of sleep debt on sleep pro...

Detrimental consequences of chronic sleep restriction on cognitive function are well established in the literature. However, effects of a single night of sleep restriction remain equivocal. Therefore, we synthesized data from 44 studies to investigate effects of sleep restriction to 2–6 h sleep opportunity on sleepiness and cognition in this meta-a...

The circadian system orchestrates sleep timing and structure and is altered with increasing age. Sleep propensity, and particularly REM sleep is under strong circadian control and has been suggested to play an important role in brain plasticity. In this exploratory study, we assessed whether surface-based brain morphometry indices are associated wi...

Acute caffeine intake has been found to increase working memory (WM)-related brain activity in healthy adults without improving behavioral performances. The impact of daily caffeine intake—a ritual shared by 80% of the population worldwide—and of its discontinuation on working memory and its neural correlates remained unknown. In this double-blind,...

For hundreds of years, mankind has been influencing its sleep and waking state through the adenosinergic system. For ~100 years now, systematic research has been performed, first started by testing the effects of different dosages of caffeine on sleep and waking behaviour. About 70 years ago, adenosine itself entered the picture as a possible ligan...

Caffeine has been reported to acutely increase working memory (WM)-related brain activity without a significant enhancement in performances in healthy adults. As a ritual in the society, however, the impacts of daily caffeine intake on WM-related brain activities remain unknown. This double-blind randomized crossover study aimed to investigate the...

Caffeine elicits widespread effects in the central nervous system and is the most frequently consumed psychostimulant worldwide. First evidence indicates that, during daily intake, the elimination of caffeine may slow down, and the primary metabolite, paraxanthine, may accumulate. The neural impact of such adaptions is virtually unexplored. In this...

Caffeine elicits widespread effects in the central nervous system and is the most frequently consumed psychostimulant worldwide. First evidence indicates that, during daily intake, the elimination of caffeine may slow down, and the primary metabolite, paraxanthine, may accumulate. The neural impact of such adaptions is virtually unexplored. In this...

Acute caffeine intake can attenuate homeostatic sleep pressure and worsen sleep quality. Caffeine intake—particularly in high doses and close to bedtime—may also affect circadian-regulated rapid eye movement (REM) sleep promotion, an important determinant of subjective sleep quality. However, it is not known whether such changes persist under chron...

Neuroprotective effects of caffeine have been frequently reported in the context of disease and cognitive dysfunction as well as in epidemiological studies in humans. However, evidence on caffeine effects on neural and memory functions during daily intake in a healthy cognitive state remains scarce. This randomized double-blind placebo-controlled c...

Acute caffeine intake can delay sleep initiation and reduce sleep intensity, particularly when consumed in the evening. However, it is not clear whether these sleep disturbances disappear when caffeine is continuously consumed during daytime, which is common for most coffee drinkers. To address this question, we investigated the sleep of twenty mal...

Caffeine is commonly used to combat high sleep pressure on a daily basis. However, interference with sleep–wake regulation could disturb neural homeostasis and insufficient sleep could lead to alterations in human gray matter. Hence, in this double-blind, randomized, cross-over study, we examined the impact of 10-day caffeine (3 × 150 mg/day) on hu...

Adolescents often suffer from short and mistimed sleep. To counteract the resulting daytime sleepiness they frequently consume caffeine. However, caffeine intake may exaggerate sleep problems by disturbing sleep and circadian timing. In a 28-hour double-blind randomized crossover study, we investigated to what extent caffeine disturbs slow-wave sle...

Acute caffeine intake can attenuate homeostatic sleep pressure and worsen sleep quality. Besides, caffeine intake – particularly in high doses and close to bedtime – may also affect circadian-regulated REM sleep promotion, an important determinant of subjective sleep quality. However, it is not known whether such changes persist under chronic caffe...

Journal of Sleep Reserach, Volume29, IssueS1. Special Issue: Abstracts of the 25th Congress of the European Sleep Research Society, 22‐24 September 2020, Virtual Congress

Acute caffeine intake can delay sleep initiation and reduce sleep intensity, particularly when consumed in the evening. However, it is not clear whether these sleep disturbances disappear when caffeine is continuously consumed during daytime, which is common for most coffee drinkers. To address this question, we investigated the sleep of twenty mal...

Procedural learning declines with age and appropriately timed light exposure can improve cognitive performance in older individuals. Because cataract reduces light transmission and is associated with cognitive decline in older adults, we explored whether lens replacement (intraocular blue‐blocking [BB] or UV‐only blocking) in older patients with ca...

Background: Adolescents frequently consume caffeine with unknown consequences on sleep and circadian rhythms. In adults, the evidence indicates that caffeine acutely reduces homeostatic sleep pressure and delays the circadian timing system. Objective: Here, we investigated the acute effects of caffeine intake on the developing sleep-wake regulatory...

The literature describes a basic neurofunctional antagonism between episodic memory encoding and retrieval with opposed patterns of neural activation and deactivation, particularly in posterior midline regions. This has been coined the encoding/retrieval (E/R) flip. The present fMRI study uses an innovative task paradigm to further elucidate neurof...

We examined whether ambient lighting conditions during extended wakefulness modulate the homeostatic response to sleep loss as indexed by. slow wave sleep (SWS) and electroencephalographic (EEG) slow-wave activity (SWA) in healthy young and older volunteers. Thirty-eight young and older participants underwent 40 hours of extended wakefulness [i.e.,...

Background: Circadian and sleep-homeostatic mechanisms regulate timing and quality of wakefulness. To enhance wakefulness, daily consumption of caffeine in the morning and afternoon is highly common. However, the effects of such a regular intake pattern on circadian sleep-wake regulation are unknown. Thus, we investigated if daily daytime caffeine...

The hippocampus plays an indispensable role in episodic memory, particularly during the consolidation process. However, its precise role in retrieval of episodic memory is still ambiguous. In this study, we investigated the correlation of hippocampal morphometry and the performance in an autobiographical memory task in 27 healthy controls and 24 pa...

Disturbed sleep homeostatic states have been found to alter neuronal homeostasis and reduce grey matter (GM) volume. Caffeine intake that interferes with sleep homeostasis through antagonizing adenosine receptors can impair hippocampal synaptic strength, neurogenesis, as well as memory and learning in rats. In this study, reduced medial temporal GM...

We examined whether the ambient illuminance during extended wakefulness modulates the homeostatic increase in human deep sleep [i.e. slow wave sleep (SWS) and electroencephalographic (EEG) slow-wave activity (SWA)] in healthy young and older volunteers. Thirty-eight young and older participants underwent 40 hours of extended wakefulness [i.e. sleep...

An amendment to this paper has been published and can be accessed via a link at the top of the paper

To enhance wakefulness, daily consumption of caffeine in the morning and afternoon is highly common. However, it is unknown whether such a regular intake pattern affects timing and quality of wakefulness, as regulated by an interplay of circadian and sleep-homeostatic mechanisms. Thus, we investigated the effects of daily caffeine intake and its wi...

Introduction The acute effects of caffeine on sleepiness and cognition are well documented in habitual caffeine consumers who abstained from caffeine for several days. Sleepiness is reduced and vigilance enhanced by caffeine, particularly under high sleep pressure. There is also evidence that caffeine impacts on the circadian melatonin rhythm in vo...

Sleepiness and cognitive function vary over the 24-h day due to circadian and sleep-wake-dependent mechanisms. However, the underlying cerebral hallmarks associated with these variations remain to be fully established. Using functional magnetic resonance imaging (fMRI), we investigated brain responses associated with circadian and homeostatic sleep...

The two-process model of sleep-wake regulation posits that sleep-wake-dependent homeostatic processes interact with the circadian timing system to affect human behavior. The circadian timing system is fundamental to maintaining stable cognitive performance, as it counteracts growing homeostatic sleep pressure during daytime. Using magnetic resonanc...

We tested the effect of different lights as a countermeasure against sleep-loss decrements in alertness, melatonin and cortisol profile, skin temperature and wrist motor activity in healthy young and older volunteers under extendend wakefulness. 26 young [mean (SE): 25.0 (0.6) y)] and 12 older participants [(mean (SE): 63.6 (1.3) y)] underwent 40-h...

Objectif La quantite de sommeil a ondes lentes (SOL) chez l’homme est dependante de la duree de veille precedente. Par rapport a une veille de 16 heures, une veille prolongee de 40 heures provoque une augmentation de 60 % de SOL lors de la nuit de recuperation chez les sujets jeunes. L’objectif de ce travail est d’examiner si cette augmentation est...

Alzheimer’s disease (AD) is characterized by memory disturbances primarily caused by pathogenic mechanisms affecting medial temporal lobe structures. As proposed by current theories of memory formation, this decrease is mediated by the age of the acquired knowledge. However, they cannot fully explain specific patterns of retrograde amnesia in AD. I...

The sleep-wake cycle is regulated by a fine-tuned interplay between sleep-homeostatic and circadian mechanisms. Compelling evidence suggests that adenosine plays an important role in mediating the increase of homeostatic sleep pressure during time spent awake and its decrease during sleep. Here, we summarize evidence that adenosinergic mechanisms r...

Morning-type individuals experience more difficulties to maintain optimal attentional performance throughout a normal waking day than evening types. However, time-of-day modulations may differ across cognitive domains. Using functional magnetic resonance imaging (fMRI), we investigated how chronotype and time of day interact with working memory at...

Objectives Even though wakefulness at night leads to profound performance deterioration and is regularly experienced by shift workers, its cerebral correlates remain virtually unexplored. Methods We assessed brain activity in young healthy adults during a vigilant attention task under high and low sleep pressure during night-time, coinciding with s...

Objectif Dans cette etude nous examinons le role d’une exposition prolongee a la lumiere comme une contre-mesure aux effets deleteres d’une privation de sommeil sur la vigilance, les profils circadiens de la melatonine et du cortisol, et sur la variation de temperature et d’activite chez des sujets jeunes et âges. Methodes Vingt-six jeunes particip...

Sleep is regulated in a time-of-day dependent manner and profits working memory. However, the impact of the circadian timing system as well as contributions of specific sleep properties to this beneficial effect remains largely unexplored. Moreover, it is unclear to which extent inter-individual differences in sleep-wake regulation depend on circad...

Aims: Light has distinct non-visual effects on human physiology and behaviour, such as suppressing melatonin and sleepiness, particularly when administered in the late evening. However, whether extended light exposure has a sustained alerting and melatonin suppressing effect during extended wakefulness (40 hours) in young and older volunteers has n...

Sleep loss affects human behavior in a nonuniform manner, depending on the cognitive domain and also the circadian phase. Besides, evidence exists about stable interindividual variations in sleep loss–related performance impairments. Despite this evidence, only a few studies have considered both circadian phase and neurobehavioral domain when inves...

Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the l...

Light exposure elicits numerous effects on human physiology and behavior, such as better cognitive performance and mood. Here we investigated the role of morning light exposure as a countermeasure for impaired cognitive performance and mood under sleep restriction (SR). Seventeen participants took part of a 48h laboratory protocol, during which thr...

In human beings, homeostatic and circadian sleep-wake regulatory processes are working together for the maintenance of sleep and wakefulness at appropriate times within the 24-hour light-dark cycle. The interaction between these processes also determines time-of-day modulations in sleepiness and alertness levels, and affects performance in a series...

Sleep deprivation is highly prevalent in our 24/7 society with harmful consequences on daytime functioning on the individual level. Genetically determined, trait-like vulnerability contributes to prominent inter-individual variability in the behavioral responses to sleep loss and adverse circadian phase. We aimed at investigating the effects of dif...

Light exposure, particularly at the short-wavelength range, triggers several nonvisual responses in humans. However, the extent to which the melatonin-suppressing and alerting effect of light differs among individuals remains unknown. Here we investigated whether blue-enriched polychromatic light impacts differentially on melatonin and subjective a...

Cardiac cycle time has been shown to affect pre-attentive brainstem startle processes, such as the magnitude of acoustically evoked reflexive startle eye blinks. These effects were attributed to baro-afferent feedback mechanisms. However, it remains unclear whether cardiac cycle time plays a role in higher startle-related cognitive processes, as we...