Daily rhythms of seizure activity and behavior in a model of atypical absence epilepsy

2006 ◽  
Vol 9 (4) ◽  
pp. 564-572 ◽  
Author(s):  
Lee S. Stewart ◽  
Eduard Bercovici ◽  
Ruchica Shukla ◽  
Irina Serbanescu ◽  
Vasan Persad ◽  
...  
Keyword(s):  
Seizure Activity ◽  
Absence Epilepsy ◽  
Daily Rhythms ◽  
Atypical Absence ◽  
And Behavior

scholarly journals Asynchronous suppression of visual cortex during absence seizures

2018 ◽  
Author(s):  
Jochen Meyer ◽  
Atul Maheshwari ◽  
Jeffrey Noebels ◽  
Stelios Smirnakis
Keyword(s):  
Visual Cortex ◽  
Seizure Activity ◽  
Absence Epilepsy ◽  
Absence Seizures ◽  
Pairwise Correlation ◽  
Network Function ◽  
Calcium Indicator ◽  
And Behavior ◽  
Spike Wave

AbstractAbsence epilepsy is a common childhood disorder featuring frequent cortical spike-wave seizures with a loss of awareness and behavior. Using the calcium indicator GCaMP6 with in vivo 2-photon cellular microscopy and simultaneous electrocorticography, we examined the collective activity profiles of individual neurons and surrounding neuropil across all layers in V1 during spike-wave seizure activity over prolonged periods in stargazer mice. We show that most (∼80%) neurons in all cortical layers reduce their activity during seizures, whereas a smaller pool activates or remains neutral. Unexpectedly, ictal participation of identified single unit activity is not fixed, but fluctuates on a flexible time scale across seizures. Pairwise correlation analysis of calcium activity reveals a surprising lack of synchrony among neurons and neuropil patches in all layers during seizures. Our results demonstrate an asynchronous suppression of visual cortex during absence seizures, with major implications for understanding cortical network function during EEG states of reduced awareness.

scholarly journals Levetiracetam and Rufinamide are effective at supressing spike and wave seizure activity in an in vitro model of absence epilepsy

2018 ◽  
Author(s):  
Virdziniha Todorova ◽  
Georgina Ford ◽  
Roger D. Traub ◽  
Miles. A. Whittington ◽  
Stephen. P. Hall
Keyword(s):  
In Vitro Model ◽  
Seizure Activity ◽  
Absence Epilepsy ◽  
Absence Seizures ◽  
Clinical Burden ◽  
Different Types ◽  
Vitro Model ◽  
Atypical Absence ◽  
Component Amplitude

AbstractSpike-and-wave discharges (SpW) are seen in absence-type epilepsies. They are heterogeneous in terms of their clinical burden and their electrographic signature, which is used to classify different types of absence seizures; typical absence, in which SpW frequency is 3-4Hz and atypical absence, which shows a slower 1-2Hz frequency. Treatment of SpW varies dependent upon the syndrome, but both Valproic Acid (VPA) and Ethosuximide (ESM) are shown to be effective in controlling typical absence seizures. Other anti-epileptic’s (AED’s), Levetiracetam (LEV) and Rufinamide (RUF), have shown promise in treating absence epilepsies and their associated syndromes. Here we examine the efficacy of these AED’s on an in vitro model of SpW.Both LEV and RUF show an effective reduction in both the number of SpW events and the spike component amplitude; VPA shows no effect, whilst ESM enhances the spike amplitude. Phenytoin exacerbates the SpW activity, increasing both the number of SpW, amplitude of the SpW and the number of spikes within each event. These data suggest that both LEV and RUF could be effective in the treatment of absence-type epilepsies. They also suggest this model could be an effective tool to test other AED’s aimed at treating atypical absence syndromes.

scholarly journals The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Beer ◽  
Mariela Schenk ◽  
Charlotte Helfrich-Förster ◽  
Andrea Holzschuh
Keyword(s):  
Circadian Clock ◽  
Circadian System ◽  
Evolutionary Adaptation ◽  
Solitary Bee ◽  
Daily Rhythms ◽  
Osmia Bicornis ◽  
Cavity Nesting ◽  
Impact On Survival ◽  
Life On Earth ◽  
And Behavior

AbstractLife on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon. Therefore, its eclosion from the pupal case is separated by an interjacent diapause from its emergence in spring. We show that this bee species synchronizes its emergence to the morning. The daily rhythms of emergence are triggered by temperature cycles but not by light cycles. In contrast to this, the bee’s daily rhythms in locomotion are synchronized by light cycles. Thus, we show that the circadian clock of O. bicornis is set by either temperature or light, depending on what activity is timed. Light is a valuable cue for setting the circadian clock when bees have left the nest. However, for pre-emerged bees, temperature is the most important cue, which may represent an evolutionary adaptation of the circadian system to the cavity-nesting life style of O. bicornis.

scholarly journals A Robust Model for Circadian Redox Oscillations

2019 ◽  
Author(s):  
Marta del Olmo ◽  
Achim Kramer ◽  
Hanspeter Herzel
Keyword(s):  
Negative Feedback ◽  
Feedback Loop ◽  
Redox State ◽  
Design Principle ◽  
Quantitative Description ◽  
Daily Rhythms ◽  
Basic Principles ◽  
Robust Model ◽  
Brown Adipose ◽  
And Behavior

AbstractThe circadian clock is an endogenous oscillator that controls daily rhythms in metabolism, physiology and behavior. Although the timekeeping components differ among species, a common design principle is a transcription-translation negative feedback loop. However, it is becoming clear that other mechanisms can contribute to the generation of 24 h rhythms. In mammalian adrenal gland, heart and brown adipose tissue, peroxiredoxins (Prx) exhibit 24 h rhythms in their redox state. Such rhythms are generated as a result of an inactivating hyperoxidation reaction that is reduced by coordinated import of the sulfiredoxin (Srx) into the mitochondria. However, a quantitative description of the Prx/Srx oscillating system is still missing. We investigate the basic principles that generate mitochondrial Prx/Srx rhythms using computational modeling. We observe that the previously described delay in mitochondrial Srx import, in combination with an appropriate separation of fast and slow reactions is sufficient to generate robust self-sustained relaxation-like oscillations. We find that our conceptual model can be regarded as a series of three consecutive phases and two temporal switches, highlighting the importance of delayed negative feedback and switches in the generation of oscillations.

scholarly journals Antiepileptic Effects of Lacosamide Loaded Polymers Implanted Subdurally in GAERS

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Sebastien H. Bauquier ◽  
Jonathan L. Jiang ◽  
Zhilian Yue ◽  
Alan Lai ◽  
Yu Chen ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Biodegradable Polymer ◽  
Seizure Activity ◽  
Absence Epilepsy ◽  
Control Group ◽  
Current Experiment ◽  
Polymer Sheets ◽  
The Mean ◽  
Eeg Recordings ◽  
Electroencephalogram Eeg

The current experiment investigated the ability of coaxial electrospun poly(D,L-lactide-co-glycolide) (PLGA) biodegradable polymer implants loaded with the antiepileptic drugs (AED) lacosamide to reduce seizures following implantation above the motor cortex in the Genetic Absence Epilepsy Rat from Strasbourg (GAERS). In this prospective, randomized, masked experiments, GAERS underwent surgery for implantation of skull electrodes (n=6), skull electrodes and blank polymers (n=6), or skull electrodes and lacosamide loaded polymers (n=6). Thirty-minute electroencephalogram (EEG) recordings were started at day 7 after surgery and continued for eight weeks. The number of SWDs and mean duration of one SWD were compared week-by-week between the three groups. There was no difference in the number of SWDs between any of the groups. However, the mean duration of one SWD was significantly lower in the lacosamide polymer group for up to 7 weeks when compared to the control group (0.004<p<0.038). The mean duration of one seizure was also lower at weeks 3, 5, 6, and 7 when compared to the blank polymer group (p= 0.016, 0.037, 0.025, and 0.025, resp.). We have demonstrated that AED loaded PLGA polymer sheets implanted on the surface of the cortex could affect seizure activity in GAERS for a sustained period.

scholarly journals Astrocytes Regulate Daily Rhythms in the Suprachiasmatic Nucleus and Behavior

2017 ◽  
Vol 27 (7) ◽  
pp. 1055-1061 ◽  
Author(s):  
Chak Foon Tso ◽  
Tatiana Simon ◽  
Alison C. Greenlaw ◽  
Tanvi Puri ◽  
Michihiro Mieda ◽  
...  
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Daily Rhythms ◽  
And Behavior

Physiological and anatomic evidence for regulation of the heart by suprachiasmatic nucleus in rats

2001 ◽  
Vol 280 (3) ◽  
pp. H1391-H1399 ◽  
Author(s):  
F. A. J. L. Scheer ◽  
G. J. Ter Horst ◽  
J. van der Vliet ◽  
R. M. Buijs
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Wistar Rats ◽  
Pseudorabies Virus ◽  
Biological Clock ◽  
Daily Rhythms ◽  
Light At Night ◽  
Male Wistar Rats ◽  
Virus Tracing ◽  
And Behavior

The suprachiasmatic nucleus (SCN) is the mammalian biological clock that generates the daily rhythms in physiology and behavior. Light can phase shift the rhythm of the SCN but can also acutely affect SCN activity and output, e.g., output to the pineal. Recently, multisynaptic SCN connections to other organs were also demonstrated. Moreover, they were shown to affect those organs functionally. The aim of the present study was to investigate the role of the SCN in the regulation of the heart. First, we demonstrated that heart rate (HR) in SCN-intact, but not SCN-lesioned (SCNx), male Wistar rats had a clear circadian rhythm, which was not caused by locomotor activity. Second, we demonstrated that light at night reduces HR in intact but not in SCNx rats. Finally, we demonstrated the presence of a multisynaptic autonomic connection from SCN neurons to the heart with the retrograde pseudorabies virus tracing technique. Together, these results demonstrate that the SCN affects the heart in rats and suggest that this is mediated by a neuronal mechanism.

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