Arcady Putilov

Independent Research Group "Math-modelling of Biomedical Systems"

It is with deepest sorrow that we announce the death of the founding editor-in-chief of Biological Rhythm Research, Prof. Rietveld, Wopke Johannes. Wop passed away in June 2024, at age 86.

Background. Sleepiness assessment tools were mostly developed for detection of an elevated sleepiness level in the condition of sleep deprivation and several medical conditions. However, sleepiness occurs in various other conditions including the transition from wakefulness to sleep during an everyday attempt to get sleep. Objective. We examined wh...

Pafnuty Chebyshev (1821-1894) is considered to be a founding father of Russian mathematics. Once, he visited Paris to give a talk entitled "Optimal cutting fabric". It brought together almost all the Parisian tailors in the big lecture hall… About five people left after his first phrase sounds like "Let's assume that a person has the shape of a bal...

Purpose The shifts in the opposite directions, toward later and earlier sleep timing, occur during the transition through adolescence and adulthood, respectively. Such a n-shape of age-associated change in sleep timing does not resemble the inverse relationship of sleep duration with ages. Age-associated variation in the parameters of the mechanism...

Although objectively measured characteristics of sleep efficiency and quality were found to be better in women than men, women more frequently than men suffer from poor or insufficient or non-restorative sleep. We explored this apparent paradox by testing the sex-associated differences in electroencephalographic (EEG) indicators of two opponent pro...

Background: Drosophila melanogaster provides a powerful platform to study the physiology and genetics of aging, i.e., the mechanisms underpinnings healthy aging, age-associated disorders, and acceleration of the aging process under adverse environmental conditions. Here, we tested the responses of daily rhythms to age-accelerated factors in two wi...

Evidence is gradually accumulating in support of the hypothesis that a process of thermo-static brain cooling and warming underlies sleep cycles, i.e., the alternations between non-rapid-eye-movement and rapid-eye-movement sleep throughout the sleep phase of the sleep-wake cycle. A mathematical thermostat model predicts an exponential shape of fluc...

Sleep is quantitatively described by subdividing polysomnographic records into intervals each of which is allocated to one of the just 5 all-or- nothing variables called “sleep–wake stages”. What are the mechanisms governing the establishment of such 5 relatively stable stages and rapid transitions between them? We modeled these stages as resulting...

Introduction: Several widely held explanations of the mechanisms underlying the responses of endogenous sleep-wake-regulating processes to early weekday wakeups have been proposed. Here, they were briefly reviewed and validated against simulations based on the rhythmostatic version of a two-process model of sleep-wake regulation. Methods: Simulated...

Introduction: Several widely held explanations of the mechanisms underlying the responses of endogenous sleep–wake-regulating processes to early weekday wakeups have been proposed. Here, they were briefly reviewed and validated against simulations based on the rhythmostatic version of a two-process model of sleep–wake regulation. Methods: Simulated...

Compared to literature on seasonal variation in mood and well-being, reports on seasonality of trouble sleeping are scarce and contradictive. To extend geography of such reports on example of people naturally exposed to high-amplitude annual variation in daylength and/or temperature. Participants were the residents of Turkmenia, West Siberia, South...

Diurnal variation in vigilance states and substates is associated with changes in electroencephalographic waves. These waves can serve as the indicators of the processes regulating rhythmicity of sleep and wakefulness states, alertness and sleepiness substates, performance and attention levels, etc. In particular, one of such indicators, alpha wave...

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1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gra...

The association of insufficient sleep with reduced self-perceived health was previously well established. Moreover, it was sometimes shown that the indicators of poorer health were sig- nificantly related to chronotype and weekday-weekend gaps in sleep timing and duration. It remains to be elucidated, however, whether chronotype and these gaps can...

Background: Activity plays a very important role in keeping bodies strong and healthy, slowing senescence, and decreasing morbidity and mortality. Drosophila models of evolution under various selective pressures can be used to examine whether increased activity and decreased sleep duration are associated with the adaptation of this nonhuman specie...

Belgium has one of the highest numbers of COVID-19 cases per 1 million inhabitants. The pandemic has led to significant societal changes with repercussions on sleep and on mental health. We aimed to investigate the effect of the first and the second wave of COVID-19 on the sleep of the Belgian populationWe launched two online questionnaires, one du...

Methods of evaluation of substates of sleep and sleepiness differ in, at least, two respects. Although sleepiness has not been separated from other wake and sleep substates using yes-or-no criteria for sleep scoring, it would be consciously perceived and, therefore, assessed with a questionary. However, such subjective method was challenged by the...

In 2016, a mini-issue of Current Aging Science (CAS) entitled “Effects of Aging on Circadian and Sleep Timing” has been published to report the state of the art in the studies of the effects of aging on the circadian and sleep regulating processes. The emphasis has been given to the regulatory processes involved in age-specific problems with sleep...

Complex systems are occasionally switching between several qualitatively different modes of behavior, even in the absence of external influences. An example of such mode-switching behavior of a complex system is a sequence of changes in sleep stages observed on approximately 90-min interval of sleep cycle. We examined whether relatively stable stag...

Ligun N.V., Dorokhov V.B., Putilov A.A., Torshin V.I. Sleep of poor and good nappers under the afternoon exposure to very weak electromagnetic fields. In: B. Kryzhanovsky, W. Dunin-Barkowski, V. Redko, Y. Tiumentsev (eds.) Advances in Neural Computation, Machine Learning, and Cognitive Research VI: Selected Papers from the XXIV International Confer...

It was hypothesized that human sleep is sensitive to the fields emitted by natural sources, such as the earth’s magnetic fields and the sun’s magnetic activity. However, the experiments aimed on testing the response of sleep to such fields are scarce. A possibility of beneficial response of sleep in the afternoon to exposure to low-level (0.004 μT)...

Thyroid Nodules (TN) are frequent but mostly benign, and postoperative rate of benign TN attains the values from 70% to 90%. Therefore, there is an urgent need for identification of reliable preoperative diagnosis markers for patients with indeterminate thyroid cytology. In this study, an earlier unexplored design of research on preoperative biomar...

Featured Application: The results of this study may be implemented in recommendations for the calculation of the delay in clock time for the weekday waking time required to reduce sleep loss on weekdays. Abstract: Background: Our work/study culture is biased towards the circadian clocks of "morning types", whereas "evening types" are forced to ad...

Background Many people believe they sleep for longer time on weekend nights to make up for sleep lost on weekdays. However, results of simulations of risetimes and bedtimes on weekdays and weekends with a sleep–wake regulating model revealed their inability to prolong weekend sleep. In particular, they predicted identical durations of weekend sleep...

In Soviet Russia, eugenics movement 1) was biased toward the methods of positive rather than negative eugenics, 2) was linked to the concept of “new Soviet man” claimed by Leon Trotsky (1879-1940) - that is “a higher biological type, or, if you please, a superman” (“Literature and Revolution”, 1924),- and 3) relied on rather antagonistic ideas, suc...

The two-process conceptualization of sleep-wake regulation suggests that the biological underpinnings of the differences between morning and evening types in sleep timing and duration might be related to either the circadian process or the homeostatic process or both. The purpose of this report was to test whether morning and evening types might ha...

Just for fan: Collectively, Nation’s IQ and GDP per capita explained more than 60% of the total variation in the percentage of vaccinated by the end of yr. 2021 (populations with less than 1000000 were not included)

A model of sleep-wake regulation (Putilov, 1995) was applied for the simulations of bed- and risetimes on weekdays and weekends. Last year (2022) publications: 1. Putilov A.A., Donskaya O.G. What can make the difference between chronotypes in sleep duration? Testing similarity of their homeostatic processes. Frontiers in Neuroscience, 2022, 16:832...

PurposeSince disagreement has been found between an objective sleep propensity measured by sleep onset latency (SOL) and subjective sleepiness assessment measured by the Epworth sleepiness scale (ESS) score, distinct underlying causes and consequences were suggested for these two sleepiness measures. We addressed the issue of validation of the ESS...

The conventional staging classification reduces all patterns of sleep polysomnogram signals to a small number of yes-or-no variables labeled wake or a stage of sleep (e.g., W, N1, N2, N3, and R for wake, the 1 st , 2 nd and 3 rd stages of non-rapid-eye-movement sleep, and rapid-eye-movement sleep, respectively). However, the neurobiological underpi...

50 парам выборок людей утреннего и вечернего хронотипов. Данные симулированы с помощью модели регуляции «сон-бодрствование». Результаты. Выявлено сходство гомеостатических компонентов механизма регуляции сна-бодрствования у хронотипов одного и того же возраста. Это означает, что они резко различаются исключительно по фазовым характеристикам циркади...

PurposeMany people believe in their ability to sleep for longer time on weekends to make up for sleep lost due to early wakeups on weekdays. This widely held belief was not supported by the simulations of rise- and bedtimes on weekdays and weekends with a sleep–wake regulating model. The simulations suggested the inability to extend sleep on any of...

This is the first review in chronopsychology, a relatively new interdisciplinary area of research which has developed rapidly at the junction of chronobiology, somnology, and psychology. Chronopsychology studies the mechanisms of rhythmicity in behavior and the mind based on methods of chronobiology, somnology, and psychometry. In particular, chron...

Under national “lockdown,” the habitual late risers need not wake up early, and, similarly to the early risers, they don’t lose much sleep on weekdays. We tested whether, despite a decrease in weekday sleep loss, the difference between distinct chronotypes in health and sleep problems persisted during “lockdown.” Two online surveys were conducted f...

A multidimensional approach has been previously applied for modeling and assessment of individual differences in the ability to sleep or to stay awake at certain clock hours. More recently the 19 time-point Visuo-verbal Judgment Task (VJT) has been proposed to predict changes in sleepiness level from the morning hours to the next day afternoon. The...

Люди: Ученый Аркадий Путилов: почему бушмены высыпаются, а мы нет? (Настасья Костюкович «Главным виновником проблем со сном следует считать изобретателя лампочки—Эдисона»). Belavia OnAir, No 4-5 (133): 130-135. https://en.belavia.by/webroot/delivery/images/OnAir_2021_APR.pdf

Humans and fruit flies demonstrate similarity in sleep-wake behavior, e.g., in the pattern of sleep disturbances caused by an exposure to high temperature. Although research has provided evidence for a clear connection between sleeping problems and infertility in women, very little is known regarding the mechanisms underlying this connection. Studi...

Although significant associations between diurnal preference and restrained eating behaviors were previously reported, such reports are scarce and, in some respects, inconclusive. In this cross-sectional survey of 567 female university students aged between 17 and 23 years, we tried to clarify and extend the previous findings on chronobiological co...

Introduction Women and men experience sleep differently and the difference in intrinsic desire for sleep might underlie some of the observed male‐female differences. The objective of this cross‐sectional questionnaire study of university students was to determine male‐female differences in self‐reported sleepiness and sleep‐wake patterns. Methods...

The efforts to link the individual differences in personality to the individual differences in sleep-wake behavior have a long history. One of the topics of such research might be to determine the strength of association between these two domains of individual variation. This requires the implementation of several inventories designed for integrati...

QUŌ VĀDIS, CHRONOPSYCHOLOGY? A. A. Putilov This is the first review on chronopsychology, a relatively new interdisciplinary research field that is rapidly developing at the crossroads of chronobiology, sleep science, and psychology. By applying the methods of chronobiology, sleep science, and psychometry, it explores the mechanisms of rhythmicity...

Background: In eyes closed condition, an increase of sleepiness level is associated with a decrease of the spectral electroencephalographic (EEG) power in the fast frequency rage (i.e., alpha activity) and with an increase of the power in the slow frequency range (i.e., theta activity). It was suggested that the changes in the fast and slow freque...

Supplementary to Single-Item Chronotyping (SIC), a method to self-assess diurnal types by using 6 simple charts

Research on individual differences in the fields of chronobiology and chronopsychology mostly focuses on two – morning and evening – chronotypes. However, recent developments in these fields pointed at a possibility to extend chronotypology beyond just two chronotypes. We examined this possibility by implementing the SingleItem Chronotyping (SIC) a...

Актуальность. Люди верят, что, поспав подольше в выходные, они смогут компенсировать долг сна, накопившийся в предыдущие дни. Подобного рода убеждения до сих пор не были протестированы с помощью модели регуляции цикла «сон – бодрствование», что послужило поводом для проведения данного исследования и опровержения этого и других допущений, бытующих в...

Sleep research consistently reveals that sleep satisfaction does not accurately reflect the age-associated worsening of subjective and objective indicators of night sleep quality. It is well-known that, on the interval of ages from early to late adulthood, the characteristics of sleep-wake pattern exhibit dramatic changes. Only some of them were si...

Background and Objective Human brain appears to be able to absorb, detect, and respond to low-level extremely low-frequency electromagnetic fields (ELF EMF). Controlled laboratory studies on human sleep under exposure to such fields are scarce. Only sleep-disturbing effects on night-time sleep were reported for frequencies of 50/60 Hz, while lower...

Background and Objective Human brain appears to be able to absorb, detect, and respond to low-level extremely low-frequency electromagnetic fields (ELF EMF). Controlled laboratory studies on human sleep under exposure to such fields are scarce. Only sleep-disturbing effects on nighttime sleep were reported for frequencies of 50/60 Hz, while lower f...

Evidence is accumulating for the possibility to distinguish more than two distinct chronotypes, i.e., people would be neither morning nor intermediate nor evening types. We tried to establish four-type division into distinct chronotypes without implying any chronotypological questionnaire. A community-based online survey (n=1305) included a visuo-v...

People sleep less in response to setting social clocks earlier relative to the sun clocks. We proposed here a model-based approach for estimating sleep loss as the difference between weekend and weekday risetimes divided on the difference between weekend risetime and weekday bedtime. We compared this approach with a traditional approach to estimati...

Evidence is accumulating for the possibility to distinguish more than two distinct chronotypes, i.e., people would be neither morning nor intermediate nor evening types. We tried to establish four-type division into distinct chronotypes without implying any chronotypological questionnaire. A community-based online survey (n = 1305) included a visuo...

Afternoon nap is regarded as a potent behavioral strategy minimizing sleepiness and fatigue. The benefits of afternoon naps require the accumulation of, at least, 3 min of stage 2 sleep. However, there are practical disadvantages of nap longer than 10-15 min, such as greater length of time consumed by the nap, appearance of slow wave sleep causing...

The natural cycles of night and day, and their length, remain stable in near-equatorial African regions but they vary with latitude and season in Eurasia. This new environmental factor might shape the adaptation of circadian rhythms of Eurasians after the out-of-African dispersal of their African ancestors. To identify the genetic-based signatures...