Katharina Blatter

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The effects of sleep pressure and circadian phase on neurobehavioral function can be sensitively measured with the psychomotor vigilance task (PVT). We compared PVT performance in 16 young (8 men and 8 women, 20-31 years) and 16 elderly healthy subjects (8 men and 8 women, 57-74 years) during a 40-h sleep deprivation (SD, high sleep pressure) and a 40-h(More)
The investigation of time-of-day effects on cognitive performance began in the early days of psychophysiological performance assessments. Since then, standardised, highly controlled protocols (constant routine and forced desynchrony) and a standard performance task (psychomotor vigilance task) have been developed to quantify sleep-wake homeostatic and(More)
The reduction of electroencephalographic (EEG) slow-wave activity (SWA) (EEG power density between 0.75-4.5 Hz) and spindle frequency activity, together with an increase in involuntary awakenings during sleep, represent the hallmarks of human sleep alterations with age. It has been assumed that this decrease in non-rapid eye movement (NREM) sleep(More)
The behavioral functions of rewards comprise the induction of learning and approach behavior. Rewards are not only related to vegetative states of hunger, thirst and reproduction but may also consist of visual stimuli. The present experiment tested the reward potential of different types of still and moving pictures in three operant tasks involving key(More)
Sleep loss has marked and selective effects on brain wave activity during subsequent recovery sleep. The electroencephalogram (EEG) responds to sleep deprivation with a relative increase in power density in the delta and theta range during non-rapid eye movement sleep. We investigated age-related changes of the EEG response to sleep deprivation along the(More)
Prefrontal cortex (PFC)-related functions are particularly sensitive to sleep loss. However, their repeated examination is intricate because of methodological constraints such as practice effects and loss of novelty. We investigated to what extent the circadian timing system and the sleep homeostat influence PFC-related performance in differently difficult(More)
There is mounting evidence for the involvement of the sleep-wake cycle and the circadian system in the pathogenesis of major depression. However, only a few studies so far focused on sleep and circadian rhythms under controlled experimental conditions. Thus, it remains unclear whether homeostatic sleep pressure or circadian rhythms, or both, are altered in(More)
Subjective well-being largely depends on mood, which shows circadian rhythmicity and can be linked to rhythms in many physiological circadian markers, such as melatonin and cortisol. In healthy young volunteers mood is influenced by an interaction of circadian phase and the duration of time awake. The authors analyzed this interaction under differential(More)
STUDY OBJECTIVES Sleep spindles exhibit a clear circadian modulation in healthy younger people. During the biological night (when melatonin is secreted), spindle density and spindle amplitude are high and spindle frequency and its variability are low, as compared with the biological day. We investigated whether this circadian modulation of spindle(More)
Orientation and self-location within the temporal fabric of the environment involves multiple organismic systems. While temporal self-location on the physiological level has been known for some time to be based on a 'biological clock' located within the hypothalamus, the mechanisms that participate in temporal position finding on the cognitive level are not(More)