The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Jerry C. P. Yin - One of the best experts on this subject based on the ideXlab platform.
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Circadian Rhythms and memory formation
Nature Reviews Neuroscience, 2010Co-Authors: Jason R. Gerstner, Jerry C. P. YinAbstract:Circadian cycling of biological processes is widely conserved across phylogeny. Gerstner and Yin discuss how regulators of Circadian Rhythms — including clock genes, melatonin and the suprachiasmatic nucleus — affect synaptic plasticity and memory formation. There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of Circadian Rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie Circadian rhythmicity and long-term memory formation. The regulation of memory formation by Circadian Rhythms and/or time-of-day effects is phylogenetically conserved in many species — including invertebrates and vertebrates — and correlates with cycling levels of melatonin. These features may be independent of changes in behavioural state (that is, wakefulness and sleep). The time-of-day-dependent regulation of neurophysiological parameters, such as spontaneous firing rate and resting membrane potential of neurons, are also phylogenetically conserved between invertebrate and vertebrate models. Circadian and time-of-day-dependent regulation of synaptic plasticity occurs in various mammalian models and can be considered a natural form of metaplasticity. Across phylogeny, similar molecular machinery underlies the processes of generating Circadian Rhythms and memory formation. These involve the expression of clock genes and the cyclic AMP–mitogen-activated protein kinase (MAPK)–cAMP-responsive element-binding protein (CREB) cascade. The maintenance of long-term memory seems to require oscillation of the cAMP–MAPK–CREB pathway. From these data, a model emerges suggesting that this maintenance of memory requires essentially autonomous molecular oscillators within memory-forming cells.
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Circadian Rhythms and memory formation.
Nature reviews. Neuroscience, 2010Co-Authors: Jason R. Gerstner, Jerry C. P. YinAbstract:There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of Circadian Rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie Circadian rhythmicity and long-term memory formation.
Clifford B. Saper - One of the best experts on this subject based on the ideXlab platform.
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differential rescue of light and food entrainable Circadian Rhythms
Science, 2008Co-Authors: Patrick M Fuller, Clifford B. SaperAbstract:When food is plentiful, Circadian Rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their Circadian Rhythms to match the food availability. We studied the basis for entrainment of Circadian Rhythms by food and light in mice with targeted disruption of the clock gene Bmal1, which lack Circadian rhythmicity. Injection of a viral vector containing the Bmal1 gene into the suprachiasmatic nuclei of the hypothalamus restored light-entrainable, but not food-entrainable, Circadian Rhythms. In contrast, restoration of the Bmal1 gene only in the dorsomedial hypothalamic nucleus restored the ability of animals to entrain to food but not to light. These results demonstrate that the dorsomedial hypothalamus contains a Bmal1-based oscillator that can drive food entrainment of Circadian Rhythms.
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the dorsomedial hypothalamic nucleus is critical for the expression of food entrainable Circadian Rhythms
Nature Neuroscience, 2006Co-Authors: Clifford B. Saper, Joshua J. Gooley, Ashley SchomerAbstract:Circadian Rhythms of behavior and physiology can be entrained by daily cycles of restricted food availability, but the pathways that mediate food entrainment are unknown. The dorsomedial hypothalamic nucleus (DMH) is critical for the expression of Circadian Rhythms and receives input from systems that monitor food availability. Here we report that restricted feeding synchronized the daily rhythm of DMH activity in rats such that c-Fos expression in the DMH was highest at scheduled mealtime. During food restriction, unlesioned rats showed a marked preprandial rise in locomotor activity, body temperature and wakefulness, and these responses were blocked by cell-specific lesions in the DMH. Furthermore, the degree of food entrainment correlated with the number of remaining DMH neurons, and lesions in cell groups surrounding the DMH did not block entrainment by food. These results establish that the neurons of the DMH have a critical role in the expression of food-entrainable Circadian Rhythms.
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The hypothalamic integrator for Circadian Rhythms.
Trends in neurosciences, 2005Co-Authors: Clifford B. Saper, Thomas C. Chou, Joshua J. GooleyAbstract:Although the suprachiasmatic nucleus (SCN) is well established as providing a genetically based clock for timing Circadian Rhythms, the mechanisms by which the timing signal is translated into Circadian Rhythms of behavior and underlying physiology have only recently come to light. The bulk of the SCN outflow terminates in a column of tissue that arches upward and backward from the SCN, and which includes the subparaventricular zone (SPZ) and the dorsomedial nucleus of the hypothalamus. Neurons within the dorsal SPZ are necessary for organizing Circadian Rhythms of body temperature, whereas neurons in the ventral SPZ are needed for Circadian Rhythms of sleep and waking. Ventral SPZ neurons in turn relay to the dorsomedial nucleus, which is crucial for producing Circadian Rhythms of sleep and waking, locomotor activity, feeding and corticosteroid production. This multistage processor provides the animal with flexibility so that environmental cues, such as food availability, ambient temperature and social interactions, can be integrated with the clock signal to sculpt an adaptive pattern of rhythmic daily activities that maximize the chances of survival and reproduction.
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critical role of dorsomedial hypothalamic nucleus in a wide range of behavioral Circadian Rhythms
The Journal of Neuroscience, 2003Co-Authors: Thomas C. Chou, Joshua J. Gooley, Thomas E Scammell, Stephanie E Gaus, Clifford B. SaperAbstract:The suprachiasmatic nucleus (SCN) contains the brain's Circadian pacemaker, but mechanisms by which it controls Circadian Rhythms of sleep and related behaviors are poorly understood. Previous anatomic evidence has implicated the dorsomedial hypothalamic nucleus (DMH) in Circadian control of sleep, but this hypothesis remains untested. We now show that excitotoxic lesions of the DMH reduce Circadian Rhythms of wakefulness, feeding, locomotor activity, and serum corticosteroid levels by 78-89% while also reducing their overall daily levels. We also show that the DMH receives both direct and indirect SCN inputs and sends a mainly GABAergic projection to the sleep-promoting ventrolateral preoptic nucleus, and a mainly glutamate-thyrotropin-releasing hormone projection to the wake-promoting lateral hypothalamic area, including orexin (hypocretin) neurons. Through these pathways, the DMH may influence a wide range of behavioral Circadian Rhythms.
Joshua J. Gooley - One of the best experts on this subject based on the ideXlab platform.
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the dorsomedial hypothalamic nucleus is critical for the expression of food entrainable Circadian Rhythms
Nature Neuroscience, 2006Co-Authors: Clifford B. Saper, Joshua J. Gooley, Ashley SchomerAbstract:Circadian Rhythms of behavior and physiology can be entrained by daily cycles of restricted food availability, but the pathways that mediate food entrainment are unknown. The dorsomedial hypothalamic nucleus (DMH) is critical for the expression of Circadian Rhythms and receives input from systems that monitor food availability. Here we report that restricted feeding synchronized the daily rhythm of DMH activity in rats such that c-Fos expression in the DMH was highest at scheduled mealtime. During food restriction, unlesioned rats showed a marked preprandial rise in locomotor activity, body temperature and wakefulness, and these responses were blocked by cell-specific lesions in the DMH. Furthermore, the degree of food entrainment correlated with the number of remaining DMH neurons, and lesions in cell groups surrounding the DMH did not block entrainment by food. These results establish that the neurons of the DMH have a critical role in the expression of food-entrainable Circadian Rhythms.
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The hypothalamic integrator for Circadian Rhythms.
Trends in neurosciences, 2005Co-Authors: Clifford B. Saper, Thomas C. Chou, Joshua J. GooleyAbstract:Although the suprachiasmatic nucleus (SCN) is well established as providing a genetically based clock for timing Circadian Rhythms, the mechanisms by which the timing signal is translated into Circadian Rhythms of behavior and underlying physiology have only recently come to light. The bulk of the SCN outflow terminates in a column of tissue that arches upward and backward from the SCN, and which includes the subparaventricular zone (SPZ) and the dorsomedial nucleus of the hypothalamus. Neurons within the dorsal SPZ are necessary for organizing Circadian Rhythms of body temperature, whereas neurons in the ventral SPZ are needed for Circadian Rhythms of sleep and waking. Ventral SPZ neurons in turn relay to the dorsomedial nucleus, which is crucial for producing Circadian Rhythms of sleep and waking, locomotor activity, feeding and corticosteroid production. This multistage processor provides the animal with flexibility so that environmental cues, such as food availability, ambient temperature and social interactions, can be integrated with the clock signal to sculpt an adaptive pattern of rhythmic daily activities that maximize the chances of survival and reproduction.
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critical role of dorsomedial hypothalamic nucleus in a wide range of behavioral Circadian Rhythms
The Journal of Neuroscience, 2003Co-Authors: Thomas C. Chou, Joshua J. Gooley, Thomas E Scammell, Stephanie E Gaus, Clifford B. SaperAbstract:The suprachiasmatic nucleus (SCN) contains the brain's Circadian pacemaker, but mechanisms by which it controls Circadian Rhythms of sleep and related behaviors are poorly understood. Previous anatomic evidence has implicated the dorsomedial hypothalamic nucleus (DMH) in Circadian control of sleep, but this hypothesis remains untested. We now show that excitotoxic lesions of the DMH reduce Circadian Rhythms of wakefulness, feeding, locomotor activity, and serum corticosteroid levels by 78-89% while also reducing their overall daily levels. We also show that the DMH receives both direct and indirect SCN inputs and sends a mainly GABAergic projection to the sleep-promoting ventrolateral preoptic nucleus, and a mainly glutamate-thyrotropin-releasing hormone projection to the wake-promoting lateral hypothalamic area, including orexin (hypocretin) neurons. Through these pathways, the DMH may influence a wide range of behavioral Circadian Rhythms.
Jason R. Gerstner - One of the best experts on this subject based on the ideXlab platform.
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Circadian Rhythms and memory formation
Nature Reviews Neuroscience, 2010Co-Authors: Jason R. Gerstner, Jerry C. P. YinAbstract:Circadian cycling of biological processes is widely conserved across phylogeny. Gerstner and Yin discuss how regulators of Circadian Rhythms — including clock genes, melatonin and the suprachiasmatic nucleus — affect synaptic plasticity and memory formation. There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of Circadian Rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie Circadian rhythmicity and long-term memory formation. The regulation of memory formation by Circadian Rhythms and/or time-of-day effects is phylogenetically conserved in many species — including invertebrates and vertebrates — and correlates with cycling levels of melatonin. These features may be independent of changes in behavioural state (that is, wakefulness and sleep). The time-of-day-dependent regulation of neurophysiological parameters, such as spontaneous firing rate and resting membrane potential of neurons, are also phylogenetically conserved between invertebrate and vertebrate models. Circadian and time-of-day-dependent regulation of synaptic plasticity occurs in various mammalian models and can be considered a natural form of metaplasticity. Across phylogeny, similar molecular machinery underlies the processes of generating Circadian Rhythms and memory formation. These involve the expression of clock genes and the cyclic AMP–mitogen-activated protein kinase (MAPK)–cAMP-responsive element-binding protein (CREB) cascade. The maintenance of long-term memory seems to require oscillation of the cAMP–MAPK–CREB pathway. From these data, a model emerges suggesting that this maintenance of memory requires essentially autonomous molecular oscillators within memory-forming cells.
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Circadian Rhythms and memory formation.
Nature reviews. Neuroscience, 2010Co-Authors: Jason R. Gerstner, Jerry C. P. YinAbstract:There has been considerable progress in elucidating the molecular mechanisms that contribute to memory formation and the generation of Circadian Rhythms. However, it is not well understood how these two processes interact to generate long-term memory. Recent studies in both vertebrate and invertebrate models have shown time-of-day effects on neurophysiology and memory formation, and have revealed a possible role for cycling molecules in memory persistence. Together, these studies suggest that common mechanisms underlie Circadian rhythmicity and long-term memory formation.
Shimon Amir - One of the best experts on this subject based on the ideXlab platform.
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The aging clock: Circadian Rhythms and later life
Journal of Clinical Investigation, 2017Co-Authors: Suzanne Hood, Shimon AmirAbstract:Circadian Rhythms play an influential role in nearly all aspects of physiology and behavior in the vast majority of species on Earth. The biological clockwork that regulates these Rhythms is dynamic over the lifespan: rhythmic activities such as sleep/wake patterns change markedly as we age, and in many cases they become increasingly fragmented. Given that prolonged disruptions of normal Rhythms are highly detrimental to health, deeper knowledge of how our biological clocks change with age may create valuable opportunities to improve health and longevity for an aging global population. In this Review, we synthesize key findings from the study of Circadian Rhythms in later life, identify patterns of change documented to date, and review potential physiological mechanisms that may underlie these changes.
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Photic regulation of Circadian Rhythms and the expression of p75 neurotrophin receptor immunoreactivity in the suprachiasmatic nucleus in rats.
Brain research, 2001Co-Authors: Christian Beaulé, Shimon AmirAbstract:Neurotrophic factors have been implicated in the mechanism underlying photic regulation of Circadian Rhythms in mammals. In rats, the most abundant neurotrophin receptor found in the suprachiasmatic nucleus (SCN), the Circadian clock, is the low affinity p75 neurotrophin receptor (p75NTR). This receptor is expressed by retinal afferents of the SCN, but nothing is known about its role in photic regulation of Circadian Rhythms. We show here that neonatal treatment with the retinal neurotoxin, monosodium glutamate (MSG), which has no effect on photic entrainment of Circadian Rhythms, nearly completely abolished p75NTR immunoreactivity in the SCN in rats. These findings suggest that p75NTR from retinal sources do not play an essential role in the mechanism mediating photic entrainment of Circadian Rhythms in rats.