Endogenous rhythm of absence epilepsy: Relationship with general motor activity and sleep–wake states

Smyk, Magdalena K.; Coenen, A.M.L.; Lewandowski, M.H.; Luijtelaar, Gilles van

doi:10.1016/j.eplepsyres.2010.11.003

Cited by 44 publications

(58 citation statements)

References 47 publications

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“…A second hormonal issue that can be proposed is that the composition of the GABA-subunits is different in different phases of the cycle and/or that the speed of change in progesterone levels is crucial for the type of changes in GABA subunits. Non-hormonal factors determining absence seizures are arousal, locomotor activity, and sleep (van Luijtelaar et al, 1991; Coenen et al, 1995; Drinkenburg et al, 1991; Osterhagen et al., 2010; Smyk et al, 2011). Early evidence suggested a significant modulation of locomotor activity and sleep–wake cycles by ovarian steroids in female rats (Colvin et al, 1968).…”

Section: Role Of Sex Hormones On Absence Epilepsy and Seizuresmentioning

confidence: 99%

Animal models of absence epilepsies: What do they model and do sex and sex hormones matter?

Luijtelaar

Onat

Gallagher

2014

Neurobiology of Disease

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While epidemiological data suggest a female prevalence in human childhood- and adolescence-onset typical absence epilepsy syndromes, the sex difference is less clear in adult-onset syndromes. In addition, although there are more females than males diagnosed with typical absence epilepsy syndromes, there is a paucity of studies on sex differences in seizure frequency and semiology in patients diagnosed with any absence epilepsy syndrome. Moreover, it is unknown if there are sex differences in the prevalence or expression of atypical absence epilepsy syndromes. Surprisingly, most studies of animal models of absence epilepsy either did not investigate sex differences, or failed to find sex-dependent effects. However, various rodent models for atypical syndromes such as the AY9944 model (prepubertal females show a higher incidence than prepubertal males), BN model also with a higher prevalence in males and the Gabra1 deletion mouse in the C57BL/6J strain offer unique possibilities for the investigation of the mechanisms involved in sex differences. Although the mechanistic bases for the sex differences in humans or these three models are not yet known, studies of the effects of sex hormones on seizures have offered some possibilities. The sex hormones progesterone, estradiol and testosterone exert diametrically opposite effects in genetic absence epilepsy and pharmacologically-evoked convulsive types of epilepsy models. In addition, acute pharmacological effects of progesterone on absence seizures during proestrus are opposite to those seen during pregnancy. 17β-Estradiol has anti-absence seizure effects, but it is only active in atypical absence models. It is speculated that the pro-absence action of progesterone, and perhaps also the delayed pro-absence action of testosterone, are mediated through the neurosteroid allopregnanolone and its structural and functional homolog, androstanediol. These two steroids increase extrasynaptic thalamic tonic GABAergic inhibition by selectively targeting neurosteroid-selective subunits of GABAA receptors (GABAARs). Neurosteroids also modulate the expression of GABAAR containing the γ2, α4, and δ subunits. It is hypothesized that differences in subunit expression during pregnancy and ovarian cycle contribute to the opposite effects of progesterone in these two hormonal states.

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Section: Role Of Sex Hormones On Absence Epilepsy and Seizuresmentioning

confidence: 99%

Animal models of absence epilepsies: What do they model and do sex and sex hormones matter?

Luijtelaar

Onat

Gallagher

2014

Neurobiology of Disease

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“…st , lh , tg ). In the Wistar Albino Glaxo (WAG) rats, 56% of SWDs occur during the wake state (15% and 39% during active and quiet wakefulness, respectively) and 46% during sleep (35% in non-REM and 11% in REM sleep) [88]. In Fisher 344 rats, SWDs (or High Voltage Spindles as they used to be called in this model) are observed only during awake immobility and are quite distinct from sleep spindles, which are of lower amplitude and rarely observed in the immobile awake condition [46].…”

Section: Occurrence Of Swds Across the Wake–sleep Cyclementioning

confidence: 99%

From sleep spindles of natural sleep to spike and wave discharges of typical absence seizures: is the hypothesis still valid?

Leresche

Lambert

Errington

et al. 2011

Pflugers Arch - Eur J Physiol

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The temporal coincidence of sleep spindles and spike-and-wave discharges (SWDs) in patients with idiopathic generalized epilepsies, together with the transformation of spindles into SWDs following intramuscular injection of the weak GABAA receptor (GABAAR) antagonist, penicillin, in an experimental model, brought about the view that SWDs may represent ‘perverted’ sleep spindles. Over the last 20 years, this hypothesis has received considerable support, in particular by in vitro studies of thalamic oscillations following pharmacological/genetic manipulations of GABAARs. However, from a critical appraisal of the evidence in absence epilepsy patients and well-established models of absence epilepsy it emerges that SWDs can occur as frequently during wakefulness as during sleep, with their preferential occurrence in either one of these behavioural states often being patient dependent. Moreover, whereas the EEG expression of both SWDs and sleep spindles requires the integrity of the entire cortico-thalamo-cortical network, SWDs initiates in cortex while sleep spindles in thalamus. Furthermore, the hypothesis of a reduction in GABAAR function across the entire cortico-thalamo-cortical network as the basis for the transformation of sleep spindles into SWDs is no longer tenable. In fact, while a decreased GABAAR function may be present in some cortical layers and in the reticular thalamic nucleus, both phasic and tonic GABAAR inhibitions of thalamo-cortical neurons are either unchanged or increased in this epileptic phenotype. In summary, these differences between SWDs and sleep spindles question the view that the EEG hallmark of absence seizures results from a transformation of this EEG oscillation of natural sleep.

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“…Considering the close relationship between SWDs and the state of vigilance, it is relevant to wonder whether the changes in SWDs' occurrence are due to changes in cortical excitability or are due to changes in behavior which might secondarily cause changes in SWDs. It is well demonstrated that SWDs preferentially occur during passive wakefulness, drowsiness, and light slow-wave sleep [25,38]. However, the suppressive effects of cathodal tDCS on the number of SWDs as found during stimulation in Exps II and III can be explained more likely by changes in membrane polarization than behavior.…”

Section: Effects Of Repetitive Cathodal Stimulation During Stimulationmentioning

confidence: 97%

“…Differences in absolute and relative power between the baseline and during stimulation were compared for each of six different frequency bands (sub-delta (b1 Hz), delta (1-4 Hz), theta (5-7 Hz), alpha (8-12 Hz), beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and gamma (31-100 Hz)) with an ANOVA, with day, time of day, and frequency bands as within-subjects factors.…”

Section: Experiments II and Iiimentioning

confidence: 99%

“…Next, acute (during stimulation), longer-lasting (1-hour 45-minute post-stimulation intervals), and long-term (24 h) effects of repetitive cathodal stimulation with two different intensities were investigated on SWD occurrence. Considering the negative relation between SWDs and behavior (motor activity) [24,25], and that changes in SWDs might be secondary to the changes in behavior induced by stimulation, the effects of tDCS on behavior were explored as well.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Noninvasive transcranial direct current stimulation in a genetic absence model

Zobeiri

Luijtelaar

2013

Epilepsy & Behavior

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Endogenous rhythm of absence epilepsy: Relationship with general motor activity and sleep–wake states

Cited by 44 publications

References 47 publications

Animal models of absence epilepsies: What do they model and do sex and sex hormones matter?

Animal models of absence epilepsies: What do they model and do sex and sex hormones matter?

From sleep spindles of natural sleep to spike and wave discharges of typical absence seizures: is the hypothesis still valid?

Noninvasive transcranial direct current stimulation in a genetic absence model

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