The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Richard Stephenson - One of the best experts on this subject based on the ideXlab platform.
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a simple model for the origin of quasiperiodic Ultradian Rhythms in sleep wake state in the rat
Communicative & Integrative Biology, 2013Co-Authors: Richard StephensonAbstract:In a recent study,1 Ultradian Rhythms of rat sleep-wake behavior were found, using several methods of time series analysis, to be “quasiperiodic.” That is, Ultradian period varied apparently randomly around a mean of approximately 4 h, with no relationship between Ultradian period and time of day. Here it is proposed that a simple two-oscillator model can explain the quasiperiodic characteristic of these Rhythms. Specifically, in this model a periodic oscillator interacts with a stochastic oscillator to generate a behavioral pattern in which the period and amplitude of the simulated Ultradian waves vary randomly around an average value. Preliminary simulations support the plausibility of the model; simulated waveforms were closely similar to behavior patterns observed in adult male rats. It is hypothesized that Ultradian Rhythms in sleep-wake behavior may arise from a periodic feedback loop (e.g., the sleep-wake homeostat) coupled to a stochastic sleep-wake “flip-flop” switch.
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sleep wake behavior in the rat Ultradian Rhythms in a light dark cycle and continuous bright light
Journal of Biological Rhythms, 2012Co-Authors: Richard Stephenson, Joonbum Lim, Svetlana Famina, Aimee M Caron, Harold B DowseAbstract:Ultradian Rhythms are a prominent but little-studied feature of mammalian sleep-wake and rest-activity patterns. They are especially evident in long-term records of behavioral state in polyphasic animals such as rodents. However, few attempts have been made to incorporate Ultradian rhythmicity into models of sleep-wake dynamics, and little is known about the physiological mechanisms that give rise to Ultradian Rhythms in sleep-wake state. This study investigated Ultradian dynamics in sleep and wakefulness in rats entrained to a 12-h:12-h light-dark cycle (LD) and in rats whose circadian Rhythms were suppressed and free-running following long-term exposure to uninterrupted bright light (LL). We recorded sleep-wake state continuously for 7 to 12 consecutive days and used time-series analysis to quantify the dynamics of net cumulative time in each state (wakefulness [WAKE], rapid eye movement sleep [REM], and non-REM sleep [NREM]) in each animal individually. Form estimates and autocorrelation confirmed the ...
Lance J Kriegsfeld - One of the best experts on this subject based on the ideXlab platform.
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Ultradian Rhythms in heart rate variability and distal body temperature anticipate onset of the luteinizing hormone surge
Scientific Reports, 2020Co-Authors: Azure D Grant, M E J Newman, Lance J KriegsfeldAbstract:The menstrual cycle is characterized by predictable patterns of physiological change across timescales. Although patterns of reproductive hormones across the menstrual cycle, particularly Ultradian Rhythms, are well described, monitoring these measures repeatedly to predict the preovulatory luteinizing hormone (LH) surge is not practical. In the present study, we explored whether non-invasive measures coupled to the reproductive system: high frequency distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing, could be used to anticipate the preovulatory LH surge in women. To test this possibility, we used signal processing to examine these measures in 45 premenopausal and 10 perimenopausal cycles alongside dates of supra-surge threshold LH and menstruation. Additionally, urinary estradiol and progesterone metabolites were measured daily surrounding the LH surge in 20 cycles. Wavelet analysis revealed a consistent pattern of DBT and HRV Ultradian rhythm (2-5 h) power that uniquely enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge, suggesting that automated Ultradian rhythm monitoring may provide a novel and convenient method for non-invasive fertility assessment.
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Ultradian Rhythms in heart rate variability and distal body temperature anticipate the luteinizing hormone surge onset
bioRxiv, 2020Co-Authors: Azure D Grant, M E J Newman, Lance J KriegsfeldAbstract:The human menstrual cycle is characterized by predictable patterns of physiological change across timescales, yet non-invasive anticipation of key events is not yet possible at individual resolution. Although patterns of reproductive hormones across the menstrual cycle have been well characterized, monitoring these measures repeatedly to anticipate the preovulatory luteinizing hormone (LH) surge is not practical for fertility awareness. In the present study, we explored whether non-invasive and high frequency measures of distal body temperature (DBT), sleeping heart rate (HR), sleeping heart rate variability (HRV), and sleep timing could be used to anticipate the preovulatory LH surge in women. To test this possibility, we used signal processing to examine these measures across the menstrual cycle. Cycles were examined from both pre- (n=45 cycles) and perimenopausal (n=10 cycles) women using days of supra-surge threshold LH and dates of menstruation for all cycles. For a subset of cycles, urinary estradiol and progesterone metabolites were measured daily around the time of the LH surge. Wavelet analysis revealed a consistent inflection point of Ultradian rhythm (2-5 h) power of DBT and HRV that enabled anticipation of the LH surge at least 2 days prior to its onset in 100% of individuals. In contrast, the power of Ultradian Rhythms in heart rate, circadian Rhythms in body temperature, and metrics of sleep duration and sleep timing were not predictive of the LH surge. Together, the present findings reveal fluctuations in distal body temperature and heart rate variability that consistently anticipate the LH surge and may aid in fertility awareness.
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Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms.
Journal of biological rhythms, 2018Co-Authors: Azure D Grant, Benjamin L Smarr, Kathryn Wilsterman, Lance J KriegsfeldAbstract:Whereas long-period temporal structures in endocrine dynamics have been well studied, endocrine Rhythms on the scale of hours are relatively unexplored. The study of these Ultradian Rhythms (URs) has remained nascent, in part, because a theoretical framework unifying Ultradian patterns across systems has not been established. The present overview proposes a conceptual coupled oscillator network model of URs in which oscillating hormonal outputs, or nodes, are connected by edges representing the strength of node-node coupling. We propose that variable-strength coupling exists both within and across classic hormonal axes. Because coupled oscillators synchronize, such a model implies that changes across hormonal systems could be inferred by surveying accessible nodes in the network. This implication would at once simplify the study of URs and open new avenues of exploration into conditions affecting coupling. In support of this proposed framework, we review mammalian evidence for (1) URs of the gut-brain axis and the hypothalamo-pituitary-thyroid, -adrenal, and -gonadal axes, (2) UR coupling within and across these axes; and (3) the relation of these URs to body temperature. URs across these systems exhibit behavior broadly consistent with a coupled oscillator network, maintaining both consistent URs and coupling within and across axes. This model may aid the exploration of mammalian physiology at high temporal resolution and improve the understanding of endocrine system dynamics within individuals.
Menno P. Gerkema - One of the best experts on this subject based on the ideXlab platform.
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unmasking Ultradian Rhythms in gene expression
The FASEB Journal, 2017Co-Authors: Daan R Van Der Veen, Menno P. GerkemaAbstract:Biological oscillations with an Ultradian time scale of 1 to several hours include cycles in behavioral arousal, episodic glucocorticoid release, and gene expression. Ultradian Rhythms are thought to have an extrinsic origin because of a perceived absence of Ultradian rhythmicity in vitro and a lack of known molecular Ultradian oscillators. We designed a novel, non-spectral-analysis method of separating Ultradian from circadian components and applied it to a published gene expression dataset with an Ultradian sampling resolution. Ultradian Rhythms in mouse hepatocytes in vivo have been published, and we validated our approach using this control by confirming 175 of 323 Ultradian genes identified in a prior study and found 862 additional Ultradian genes. For the first time, we now report Ultradian expression of >900 genes in vitro Sixty genes exhibited Ultradian transcriptional rhythmicity, both in vivo and in vitro, including 5 genes involved in the cell cycle. Within these 60 genes, we identified significant enrichment of specific DNA motifs in the 1000 bp proximal promotor, some of which associate with known transcriptional factors. These findings are in strong support of instrinsically driven Ultradian Rhythms and expose potential molecular mechanisms and functions underlying Ultradian Rhythms that remain unknown.-Van der Veen, D. R., Gerkema, M. P. Unmasking Ultradian Rhythms in gene expression.
Brian J. Prendergast - One of the best experts on this subject based on the ideXlab platform.
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Ultradian Rhythms in mammalian physiology and behavior.
Current opinion in neurobiology, 2016Co-Authors: Brian J. Prendergast, Irving ZuckerAbstract:Diverse mammalian Ultradian Rhythms (URs) with periods in the 1–6 h range, are omnipresent at multiple levels of biological organization and of functional and adaptive significance. Specification of neuroendocrine substrates that generate URs remains elusive. The suprachiasmatic (SCN) and arcuate (ARC) nuclei of the rodent hypothalamus subserve several behavioral URs. Recently, in a major advance, dopaminergic signaling in striatal circuitry, likely at D2 receptors, has been implicated in behavioral and thermoregulatory URs of mice. We propose a neural network in which reciprocal communication among the SCN, the ARC and striatal dopaminergic circuitry modulates the period and waveform of behavioral and physiological URs.
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pregnancy induced changes in Ultradian Rhythms persist in circadian arrhythmic siberian hamsters
Hormones and Behavior, 2014Co-Authors: Yan Z Wang, Irving Zucker, Erin J Cable, Brian J. PrendergastAbstract:The impact of pregnancy and lactation on Ultradian Rhythms (URs) and circadian Rhythms (CRs) of locomotor activity was assessed in circadian rhythmic and arrhythmic Siberian hamsters maintained in a long-day photoperiod (16 h light/day). Progressive decrements in CR robustness and amplitude over the course of gestation were accompanied by enhanced URs. Dark-phase UR period and amplitude increased during early gestation and complexity and robustness increased during late gestation. The persistence of pregnancy-associated enhancements of URs in circadian arrhythmic (ARR) hamsters suggests that reproductive modulation of the UR waveform is not dependent on coherent circadian organization. The increased incidence of dark-phase URs appeared more rapidly in ARR dams than entrained (ENTR) dams. Throughout gestation, the percentage of dams with dark-phase URs was significantly greater in the ARR group. Gestational increases in UR complexity and robustness emerged earlier and were greater in ARR than ENTR dams. The attenuation of CRs during lactation is correlated with increased expression of URs. Relaxation of circadian control of the dam's behavior may increase fitness by permitting more efficient interactions with circadian arrhythmic pups.
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photoperiodic influences on Ultradian Rhythms of male siberian hamsters
PLOS ONE, 2012Co-Authors: Brian J. Prendergast, Irving ZuckerAbstract:Seasonal changes in mammalian physiology and behavior are proximately controlled by the annual variation in day length. Long summer and short winter day lengths markedly alter the amplitude of endogenous circadian Rhythms and may affect Ultradian oscillations, but the threshold photoperiods for inducing these changes are not known. We assessed the effects of short and intermediate day lengths and changes in reproductive physiology on circadian and Ultradian Rhythms of locomotor activity in Siberian hamsters. Males were maintained in a long photoperiod from birth (15 h light/day; 15 L) and transferred in adulthood to 1 of 7 experimental photoperiods ranging from 14 L to 9 L. Decreases in circadian rhythm (CR) robustness, mesor and amplitude were evident in photoperiods ≤14 L, as were delays in the timing of CR acrophase and expansion of nocturnal activity duration. Nocturnal Ultradian Rhythms (URs) were comparably prevalent in all day lengths, but 15 L markedly inhibited the expression of light-phase URs. The period (τ’), amplitude and complexity of URs increased in day lengths ≤13 L. Among hamsters that failed to undergo gonadal regression in short day lengths (nonresponders), τ’ of the dark-phase UR was longer than in photoresponsive hamsters; in 13 L the incidence and amplitude of light-phase URs were greater in hamsters that did not undergo testicular regression. Day lengths as long as 14 L were sufficient to trigger changes in the waveform of CRs without affecting UR waveform. The transition from a long- to a short-day Ultradian phenotype occurred for most UR components at day lengths of 12 L–13 L, thereby establishing different thresholds for CR and UR responses to day length. At the UR-threshold photoperiod of 13 L, differences in gonadal status were largely without effect on most UR parameters.
Irving Zucker - One of the best experts on this subject based on the ideXlab platform.
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Ultradian Rhythms in mammalian physiology and behavior.
Current opinion in neurobiology, 2016Co-Authors: Brian J. Prendergast, Irving ZuckerAbstract:Diverse mammalian Ultradian Rhythms (URs) with periods in the 1–6 h range, are omnipresent at multiple levels of biological organization and of functional and adaptive significance. Specification of neuroendocrine substrates that generate URs remains elusive. The suprachiasmatic (SCN) and arcuate (ARC) nuclei of the rodent hypothalamus subserve several behavioral URs. Recently, in a major advance, dopaminergic signaling in striatal circuitry, likely at D2 receptors, has been implicated in behavioral and thermoregulatory URs of mice. We propose a neural network in which reciprocal communication among the SCN, the ARC and striatal dopaminergic circuitry modulates the period and waveform of behavioral and physiological URs.
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pregnancy induced changes in Ultradian Rhythms persist in circadian arrhythmic siberian hamsters
Hormones and Behavior, 2014Co-Authors: Yan Z Wang, Irving Zucker, Erin J Cable, Brian J. PrendergastAbstract:The impact of pregnancy and lactation on Ultradian Rhythms (URs) and circadian Rhythms (CRs) of locomotor activity was assessed in circadian rhythmic and arrhythmic Siberian hamsters maintained in a long-day photoperiod (16 h light/day). Progressive decrements in CR robustness and amplitude over the course of gestation were accompanied by enhanced URs. Dark-phase UR period and amplitude increased during early gestation and complexity and robustness increased during late gestation. The persistence of pregnancy-associated enhancements of URs in circadian arrhythmic (ARR) hamsters suggests that reproductive modulation of the UR waveform is not dependent on coherent circadian organization. The increased incidence of dark-phase URs appeared more rapidly in ARR dams than entrained (ENTR) dams. Throughout gestation, the percentage of dams with dark-phase URs was significantly greater in the ARR group. Gestational increases in UR complexity and robustness emerged earlier and were greater in ARR than ENTR dams. The attenuation of CRs during lactation is correlated with increased expression of URs. Relaxation of circadian control of the dam's behavior may increase fitness by permitting more efficient interactions with circadian arrhythmic pups.
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photoperiodic influences on Ultradian Rhythms of male siberian hamsters
PLOS ONE, 2012Co-Authors: Brian J. Prendergast, Irving ZuckerAbstract:Seasonal changes in mammalian physiology and behavior are proximately controlled by the annual variation in day length. Long summer and short winter day lengths markedly alter the amplitude of endogenous circadian Rhythms and may affect Ultradian oscillations, but the threshold photoperiods for inducing these changes are not known. We assessed the effects of short and intermediate day lengths and changes in reproductive physiology on circadian and Ultradian Rhythms of locomotor activity in Siberian hamsters. Males were maintained in a long photoperiod from birth (15 h light/day; 15 L) and transferred in adulthood to 1 of 7 experimental photoperiods ranging from 14 L to 9 L. Decreases in circadian rhythm (CR) robustness, mesor and amplitude were evident in photoperiods ≤14 L, as were delays in the timing of CR acrophase and expansion of nocturnal activity duration. Nocturnal Ultradian Rhythms (URs) were comparably prevalent in all day lengths, but 15 L markedly inhibited the expression of light-phase URs. The period (τ’), amplitude and complexity of URs increased in day lengths ≤13 L. Among hamsters that failed to undergo gonadal regression in short day lengths (nonresponders), τ’ of the dark-phase UR was longer than in photoresponsive hamsters; in 13 L the incidence and amplitude of light-phase URs were greater in hamsters that did not undergo testicular regression. Day lengths as long as 14 L were sufficient to trigger changes in the waveform of CRs without affecting UR waveform. The transition from a long- to a short-day Ultradian phenotype occurred for most UR components at day lengths of 12 L–13 L, thereby establishing different thresholds for CR and UR responses to day length. At the UR-threshold photoperiod of 13 L, differences in gonadal status were largely without effect on most UR parameters.
