Circadian rhythms

…is also associated with alterations in circadian rhythms and sleep patterns. However, available data are limited.The Pahenu2

Circadian rhythms are ~24-hour oscillations that provide temporal integration of physiology and behavior that are entrained to the earth’s light-dark cycle via photic input to the suprachiasmatic nuclei (SCN). The SCN (i.e., central clock), sets central and peripheral clocks accordingly to maintain proper synchronization with the external solar day. Exposure to artificial light at night (ALAN) resets the SCN, disrupting daily internal rhythms. Our lab and others have demonstrated daily rhythms in transcellular permeability via efflux mediated transport at the blood-brain barrier (BBB). However

Depression is associated with dysregulated circadian rhythms, but the role of intrinsic clocks in mood-controlling brain regions remains poorly understood. We found increased oscillation of clock negative regulatory loop, as well as a phase shift of Bmal1 expression in the medial prefrontal cortex (mPFC) of a mouse model of depression (depression-like behavior and anhedonia induced by daily 10 min swim sessions for 5 consecutive days). Selective disruption of mPFC clockwork with viral Bmal1KO in CaMK2a excitatory neurons blocks the development of depressive-like phenotype in our model of depre

Diurnal animals with monophasic sleep patterns exhibit species-specific cycles of slow-wave sleep (SWS) alternating with rapid eye movement sleep (REMS). A recent study revealed that in the diurnal reptile Pogona vitticeps, SWS and REMS regularly alternate with approximately 2-min cycles throughout the night, generating more than 300 SWS/REMS cycles. Although the cycle varies significantly across species, common neural mechanisms may be involved. However, the precise mechanisms responsible for maintaining these regular cycles remain elusive. Sleep-wake patterns are predominantly regulated by t

…suggests that the disruption of circadian rhythms may be impacting the epilepsy phenotype. However, whether the molecular clock is a key player in epileptogenesis remains to be elucidated. Here, we mapped for the first-time the hippocampal molecular rhythmicity of mice during epileptogenesis. Methods: Male adult C57BL/6 mice (n=5/group/Zeitgeber-Times [ZTs]) underwent intra-amygdala kainic acid-induced (i.a.KA) status epilepticus or control (i.a.PBS). From 24h af

In mammals, circadian rhythms are controlled by the central clock, suprachiasmatic nuclei (SCN) in the hypothalamus. The external light signal could entrain SCN through intrinsically photosensitive retinal ganglion cells (ipRGCs), a type of neuron in the retinal of mammalian eyes, by releasing glutamate. The innervation of ipRGCs to SCN has been revealed by using genetic tracing techniques and contributes to the synchronization of the circadian rhythm. SCN is a heterogenous structure that contains different neurons, while AVP and VIP neurons are critical for the networking of circadian rhythm.

…by microglia, which are under strong circadian regulation. Circadian rhythms are 24-hour variations in physiological function orchestrated by a network of autoregulatory genes, including its key component, Bmal1. Here we explored the impact of Bmal1 knock down in microglial cells on seizure susceptibility and the CNS-immune profile.Methods: Forty young adult Bmal1-Cx3CR1Cre-ER mice were injected with either tamoxifen (40 mg/kg; IP; daily for 10 days) to ind

…genes are under the influence of the circadian rhythms. These are 24-hour endogenous rhythms that determine a large number of daily changes in physiology and behavior in our bodies. In the brain, the master clock regulates a large number of pathways that are important during epileptogenesis and established-epilepsy, such as neurotransmission, synaptic homeostasis, inflammation, blood-brain

…impact of DBS on sleep architecture, circadian rhythms, and other various sleep issues is not well understood. This paper will evaluate peer-reviewed publications on the effect of DBS on sleep, the mechanisms, and the effects for the patients. The conclusion of these questionnaires is

…among motor activity, sleep and circadian rhythms and mood disorders; (3) describe potential of cross species studies of motor activity and related systems to inform human chronobiology research

The visual system of the brain is highly parallel in its architecture. This is clearly evident in the outputs of the retina, which arise from neurons called ganglion cells. Work in our lab has shown that mammalian retinas contain more than a dozen distinct types of ganglion cells. Each type appears to filter the retinal image in a unique way and to relay this processed signal to a specific set of targets in the brain. My students and I are working to understand the meaning of this parallel organization through electrophysiological and anatomical studies. We record from light-responsive ganglio

What happens to human sleep and circadian rhythms in space? There are many challenges that affect sleep in space, including unusual patterns of light exposure and the influence of microgravity. This talk will review the causes and consequences of sleep loss and circadian misalignment during spaceflight and will discuss how missions to the Moon and Mars will be different than missions to the International Space Station.

We seek to determine how circadian rhythms and sleep are integrated with physiological processes to provide optimal fitness and health. Using initially a Drosophila model, and more recently also mammalian models, we have found that aspects of the blood brain barrier (BBB) are controlled by the circadian clock. BBB properties are also influenced by sleep:wake state in Drosophila, and, in fact, appear to be contribute to functions of sleep. This and other work, which implicates sleep in the regulation of metabolic processes, is providing insights into sleep function

…are studying how light-adaptation and circadian rhythms alter visual processing in the retina. Finally, we are working to understand the mechanisms of retinal deg

Sleep and all of the other circadian rhythms that adapt us to the 24 hour world are controlled by the suprachiasmatic nucleus (SCN), the brain's central circadian clock. And yet, the SCN consists of only 20,000 neurons and astrocytes, so what makes it such a powerful clock, able to set the tempo to our lives? Professor Hastings will consider the cell-autonomus and neural circuit-level mechanisms that sustain the SCN clock and how it regulates rest, activity and sleep.