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Research Interests: Psychology and PLoS one
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This manuscript contains the conclusion of the consensus meeting on the diagnosis of narcolepsy based on the review of Medline publications between 1980-2010. Narcolepsy is a chronic disorder with age at onset between the first and second... more
This manuscript contains the conclusion of the consensus meeting on the diagnosis of narcolepsy based on the review of Medline publications between 1980-2010. Narcolepsy is a chronic disorder with age at onset between the first and second decade of life. Essential narcolepsy symptoms are cataplexy and excessive sleepiness. Cataplexy is defined as sudden, recurrent and reversible attacks of muscle weakness triggered by emotions. Accessory narcolepsy symptoms are hypnagogic hallucinations, sleep paralysis and nocturnal fragmented sleep. The clinical diagnosis according to the International Classification of Sleep Disorders is the presence of excessive sleepiness and cataplexy. A full in-lab polysomnography followed by a multiple sleep latency test is recommended for the confirmation of the diagnosis and co-morbidities. The presence of two sleep-onset REM period naps in the multiple sleep latency test is diagnostic for cataplexy-free narcolepsy. A positive HLA-DQB1*0602 with lower than...
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Research Interests: Philosophy and Humanities
Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural... more
Dream reports collected after rapid eye movement sleep (REM) awakenings are, on average, longer, more vivid, bizarre, emotional and story-like compared to those collected after non-REM. However, a comparison of the word-to-word structural organization of dream reports is lacking, and traditional measures that distinguish REM and non-REM dreaming may be confounded by report length. This problem is amenable to the analysis of dream reports as non-semantic directed word graphs, which provide a structural assessment of oral reports, while controlling for individual differences in verbosity. Against this background, the present study had two main aims: Firstly, to investigate differences in graph structure between REM and non-REM dream reports, and secondly, to evaluate how non-semantic directed word graph analysis compares to the widely used measure of report length in dream analysis. To do this, we analyzed a set of 125 dream reports obtained from 19 participants in controlled laborato...
Research Interests: Psychology, Biology, Medicine, Multidisciplinary, Social connectedness, and 3 morePLoS one, Graph, and DREAM
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The rotation of the Earth around its own axis and around the sun determines the characteristics of the light/dark cycle, the most stable and ancient 24 h temporal cue for all organisms. Due to the tilt in the earth's axis in relation... more
The rotation of the Earth around its own axis and around the sun determines the characteristics of the light/dark cycle, the most stable and ancient 24 h temporal cue for all organisms. Due to the tilt in the earth's axis in relation to the plane of the earth's orbit around the sun, sunlight reaches the Earth differentially depending on the latitude. The timing of circadian rhythms varies among individuals of a given population and biological and environmental factors underlie this variability. In the present study, we tested the hypothesis that latitude is associated to the regulation of circadian rhythm in humans. We have studied chronotype profiles across latitudinal cline from around 0° to 32° South in Brazil in a sample of 12,884 volunteers living in the same time zone. The analysis of the results revealed that humans are sensitive to the different sunlight signals tied to differences in latitude, resulting in a morning to evening latitudinal cline of chronotypes toward...
Research Interests: Biology, Medicine, Population, Circadian Rhythm, Chronotype, and 3 moreMorning, Sunlight, and Latitude
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The circadian system is organized in a hierarchy of multiple oscillators, with the suprachiasmatic nucleus (SCN) as the master oscillator in mammals. The SCN is formed by a group of coupled cell oscillators. Knowledge of this coupling... more
The circadian system is organized in a hierarchy of multiple oscillators, with the suprachiasmatic nucleus (SCN) as the master oscillator in mammals. The SCN is formed by a group of coupled cell oscillators. Knowledge of this coupling mechanism is essential to understanding entrainment and the expression of circadian rhythms. Some authors suggest that light-dark (LD) cycles with periods near the limit of entrainment may be good models for promoting internal desynchronization, providing knowledge about the coupling mechanism. As such, we evaluated the circadian activity rhythm (CAR) pattern of marmosets in LD cycles at lower limits of entrainment in order to study induced internal dissociation. To that end, two experiments were conducted: (1) 6 adult females were under symmetrical LD cycles T21, T22 and T21.5 for 60, 35 and 48 days, respectively; and (2) 4 male and 4 female adults were under T21 for 24 days followed by 18 days of LL, back to T21 for 24 days, followed by 14 days of LL...
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Parkinson's disease motor dysfunctions are associated with improperly organised neural oscillatory activity. The presence of such disruption at the early stages of the disease in which altered sleep is one of the main features could be a... more
Parkinson's disease motor dysfunctions are associated with improperly organised neural oscillatory activity. The presence of such disruption at the early stages of the disease in which altered sleep is one of the main features could be a relevant predictive feature. Based on this, we aimed to investigate the neocortical synchronisation dynamics during slow-wave sleep (SWS) in the rotenone model of Parkinson's dis
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Disturbios do sono sao os mais comuns sintomas nao-motores encontrados na doenca de Parkinson (DP). OBJETIVOS: Avaliar a relacao entre actigrafia e disturbios do sono mais incidentes na DP. METODOS: Pacientes com e sem DP foram avaliados... more
Disturbios do sono sao os mais comuns sintomas nao-motores encontrados na doenca de Parkinson (DP). OBJETIVOS: Avaliar a relacao entre actigrafia e disturbios do sono mais incidentes na DP. METODOS: Pacientes com e sem DP foram avaliados quanto aos sintomas motores, qualidade do sono, cronotipo e objetivamente atraves do uso do actimetro. RESULTADOS: Encontrou-se uma significante reducao da qualidade do sono entre os pacientes com DP (p = 0.0023), uma pior qualidade subjetiva do sono, maior uso de medicamentos para insonia, mais disturbios do sono e uma maior fragmentacao do ritmo atividade-repouso (IV) (p=0.0271). CONCLUSAO: Pacientes com DP possuem uma pior qualidade de sono e um ritmo atividade-repouso mais fragmentado. A Actigrafia pode ser util na avaliacao da qualidade do sono e do ciclo atividade- repouso em pacientes com DP, contribuindo para o rastreio e acompanhamento de eventuais disturbios do ritmo circadiano a esta doenca associados
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Arousals can be roughly characterized by punctual intrusions of wakefulness into sleep. In a standard perspective, using human electroencephalography (EEG) data, arousals are associated to slow-wave rhythms and K-complex brain activity.... more
Arousals can be roughly characterized by punctual intrusions of wakefulness into sleep. In a standard perspective, using human electroencephalography (EEG) data, arousals are associated to slow-wave rhythms and K-complex brain activity. The physiological mechanisms that give rise to arousals during sleep are not yet fully understood. Moreover, subtle body movement patterns, which may characterize arousals both in human and in animals, are usually not detectable by eye perception and are not in general present in sleep studies. In this paper, we focus attention on accelerometer records (AR) to characterize and predict arousal during slow wave sleep (SWS) stage of mice. Furthermore, we recorded the local field potentials (LFP) from the CA1 region in the hippocampus and paired with accelerometer data. The hippocampus signal was also used here to identify the SWS stage. We analyzed the AR dynamics of consecutive arousals using recurrence technique and the determinism (DET) quantifier. R...
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Chronotype is an established concept designed to identify distinct phase relationships between the expression of circadian rhythms and external synchronizers in humans. Although it has been widely accepted that chronotype is subjected to... more
Chronotype is an established concept designed to identify distinct phase relationships between the expression of circadian rhythms and external synchronizers in humans. Although it has been widely accepted that chronotype is subjected to ontogenetic modulation, there is no consensus on the interaction between age and gender. This study aimed to determine the relationship between age-and gender-related changes in the morningness-eveningness character in a large sample of people. A total of 14,650 volunteers were asked to complete the Brazilian version of the Horne and O ¨ stberg chronotype questionnaire. The data demonstrated that, on average, women were more morning-oriented than men until the age of 30 and there were no significant differences between men and women from 30 to 45 years of age. In contrast to the situation observed until the age of 30, women older than 45 years were more evening-oriented than men. These results suggest that the ontogenetic development of the circadian timekeeping system is more plastic in men, as represented by the larger amplitude of chronotype changes throughout their aging process. The phase delay of adolescence and phase advance of the elderly seem to be phenomena that are more markedly present in men than in women. Thus, our data, for the first time, provide support that sharply opposes the view that there is a single path toward morningness as a function of age, regardless of gender.
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Arousals can be roughly characterized by punctual intrusions of wakefulness into sleep. In a standard perspective, using human electroencephalography (EEG) data, arousals are associated to slow-wave rhythms and K-complex brain activity.... more
Arousals can be roughly characterized by punctual intrusions of wakefulness into sleep. In a standard perspective, using human electroencephalography (EEG) data, arousals are associated to slow-wave rhythms and K-complex brain activity. The physiological mechanisms that give rise to arousals during sleep are not yet fully understood. Moreover, subtle body movement patterns, which may characterize arousals both in human and in animals, are usually not detectable by eye perception and are not in general present in sleep studies. In this paper, we focus attention on accelerometer records (AR) to characterize and predict arousal during slow wave sleep (SWS) stage of mice. Furthermore, we recorded the local field potentials (LFP) from the CA1 region in the hippocampus and paired with accelerome-ter data. The hippocampus signal was also used here to identify the SWS stage. We analyzed the AR dynamics of consecutive arousals using recurrence technique and the determinism (DET) quantifier. Recurrence is a fundamental property of dynamical systems, which can be exploited to characterize time series properties. The DET index evaluates how similar are the evolution of close trajectories: in this sense, it computes how accurate are predictions based on past trajectories. For all analyzed mice in this work, we observed, for the first time, the occurrence of a universal dynamic pattern a few seconds that precedes the arousals during SWS sleep stage based only on the AR signal. The predictability success of an arousal using DET from AR is nearly 90%, while similar analysis using LFP of hip-pocampus brain region reveal 88% of success. Noteworthy, our findings suggest an unique dynamical behavior pattern preceding an arousal of AR data during sleep. Thus, the employment of this technique applied to AR data may provide useful information about the dynamics of neuronal activities that control sleep-waking switch during SWS sleep period. We argue that the predictability of arousals observed through DET(AR) can be functionally explained by a respiratory-driven modification of neural states. Finally, we believe that the PLOS ONE | https://doi.
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Research Interests: Cognitive Psychology, Health Psychology, Working Memory, Cognitive Neuropsychology, Neuropsychology Of Dementia Lewy Body, Alzheimer's And Frontotemporal, and 8 moreMemory Studies, Sleep Medicine, Cognitive Neuroscience, Sleep Deprivation, Sleep disorders, Chronobiology, Sleep Regulation, Sleep and Memory Consolidation, and urgency and emergency psychology
Thesis (M.A.)--University of Kansas, Human Development, 1980. Includes bibliographical references (leaves 75-80).
The purpose of this study was to define a method for assessing skeletal tumor burden with (18)F-sodium fluoride PET/CT (fluoride-PET/CT) and evaluate the reproducibility of these measurements. Ninety-eight consecutive patients (90 males;... more
The purpose of this study was to define a method for assessing skeletal tumor burden with (18)F-sodium fluoride PET/CT (fluoride-PET/CT) and evaluate the reproducibility of these measurements. Ninety-eight consecutive patients (90 males; 65.7 ± 14.2yrs.) underwent 158 fluoride-PET/CT scans for evaluation of skeletal metastatic disease. Normal bone mean SUVs were measured over a 1 cm spherical volume of interest (VOI) placed over 5 bone sites: T12, L5, sacrum, right iliac and right femur. For each patient, average SUVs for all sites was generated. Afterwards, a threshold value of normal bone uptake was established. Subsequently, skeletal tumor burden was determined by generating volumetric data using a whole-body segmentation method. All SUVs below the established normal threshold value were excluded from analysis as were VOIs not related to metastatic disease. Statistics for the remaining VOIs were then generated and defined as the skeletal tumor burden by two parameters: total fluo...
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The public health informatics (PHI) field was defined in the peer-reviewed literature in 1995 and continuously has been described as an emerging field with the power to fundamentally change public health practice, research, and learning.... more
The public health informatics (PHI) field was defined in the peer-reviewed literature in 1995 and continuously has been described as an emerging field with the power to fundamentally change public health practice, research, and learning. Even though PHI has been recognized in the literature over the past 12 years, it remains described there as an emerging field within public health. One definitional element of a field has been described as having a base in specialized knowledge. A periodic, systematic survey of the published literature is important to characterize the increasing body of specialized knowledge in a field. This assessment examined the growth of PHI peer-reviewed literature as one indicator of a body of knowledge for PHI contributing to a formal recognition and establishment of PHI as an integral component of public health practice, research, and learning. The National Library of Medicine published PHI Current Bibliographies in Medicine (CBM) in 1996 and 2001, which wer...
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The purpose of this study was to compare energy expenditure and substrate utilization during 60 min of steady state-exercise at similar heart rates (HR) using four exercise modes: stationary cycle (C), rower (R), ski simulator (S), and... more
The purpose of this study was to compare energy expenditure and substrate utilization during 60 min of steady state-exercise at similar heart rates (HR) using four exercise modes: stationary cycle (C), rower (R), ski simulator (S), and treadmill (walking) (T). Five subjects (means age = 23 +/- 4 yr) performed 60 min of continuous exercise at 65% HR max on each of the four modes in random order. Total energy (TE) and fat energy (FE) expenditure were determined from VO2 and respiratory exchange ratio (RER). VO2 during exercise averaged 2.427 for C, 2.167 for R, 2.242 for S, and 2.420 l min-1 for T and were not significantly different by repeated measures ANOVO (p greater than 0.05). RER, TE, and FE also were not statistically different among exercise modes. However, walking and skiing tended to use more fat; the average 60 min cumulative exercise values were 960 for C, 871 for R, 1088 for S, and 1188 kJ for T. The rate of fat expenditure generally increased after 20 min on all modes. ...
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The objective of the present study was to investigate the circadian and the ultradian rhythms of drinking behavior in Wistar rats maintained under conditions of constant darkness. Six mature male rats (weighing 270-350 g) were exposed to... more
The objective of the present study was to investigate the circadian and the ultradian rhythms of drinking behavior in Wistar rats maintained under conditions of constant darkness. Six mature male rats (weighing 270-350 g) were exposed to light-dark 12:12-h cycles (LD 12:12, light on at 12:00 h) for 35 days and then switched to constant darkness (DD) conditions for at least 2 weeks. Drinking behavior was monitored continuously with a standard drinkometer circuit and the data was stored in 5-min bins. A modification of Enright's periodogram technique was used to evaluate the free-running drinking behavior circadian rhythm. Ultradian rhythms in drinking behavior were estimated by the Fast Fourier Transform (FFT) technique. Two of the animals (rats 4 and 6) showed no statistically significant circadian or ultradian rhythms and the other four showed free-running drinking circadian rhythm behavior shorter than 24 h (ranging from 23.333 to 23.967 h). Ultradian rhythms of drinking behav...
To study substrate utilization during cold temperature exercise, seven men dressed in shorts, T-shirts, and light gloves performed 60 min of continuous cycle ergometer exercise at -10 degrees C and 22 degrees C. The workload at both... more
To study substrate utilization during cold temperature exercise, seven men dressed in shorts, T-shirts, and light gloves performed 60 min of continuous cycle ergometer exercise at -10 degrees C and 22 degrees C. The workload at both temperatures represented 66% of the cycle-measured maximal heart rate. Oxygen consumption and respiratory exchange ratio (RER) were measured at rest and during 60 min of exercise. Rates of total and fat energy utilization (kJ X min-1) during exercise were calculated from VO2 and RER. A two-factor repeated measures analysis of variance indicated that at rest oxygen consumption averaged 56% higher and RER 5% lower at -10 degrees C. During exercise, oxygen consumption averaged 10% higher (P less than 0.05), and RER averaged 2% lower (P less than 0.05) at -10 degrees C. The rates of total energy use (mean +/- SD = 39.3 +/- 1.2 vs 35.7 +/- 1.3 kJ X min-1; P less than 0.05) were significantly higher at -10 degrees C than at 22 degrees C. In addition, the rate of fat use increased significantly in both groups after 30 min of exercise. The cumulative total energy expenditure for 60 min of exercise was 13% higher (2379 +/- 308 vs 2110 +/- 415 kJ; P less than 0.05 and the cumulative fat expenditure was 35% higher (979 +/- 209 vs 724 +/- 184 kJ: P less than 0.05) in the cold environment. These results indicate that a cold environment can significantly enhance fat utilization during endurance exercise.