Introduction: A typical absence epilepsy is a type of nonconvulsive and generalized epilepsy. The main feature of these attacks is a sudden brief impairment of consciousness. The disturbances in thalamocortical loop play an important role in pathogenesis of absence seizures. However, it is not clear that which part of this network triggers the seizure. This study was aimed to investigate the role of latrodorsal (LD) thalamic neurons during spike and wave discharges (SWDs) in WAG/Rij rats, as the most valid animal model of absence epilepsy.Materials and Methods: Single unit activities in the LD thalamic nucleus and electrocorticogram of somatosensory cortex were simultaneously recorded in six-month-old WAG/Rij rats.Results: During SWDs, unit activity in the LD thalamic nucleus showed burst-like discharges, which were started before the peak component of SWDs. In SWD-free periods, burst like activity in the LD was reduced.Conclusion: Our findings suggest that the burst firing of LD may stimulate the neocortex to exhibit SWDs. It can be concluded that inhibition of burst firing of LD neurons may reduce the frequency of SWDs.

Dear Editor: In allopathic medicine, absence seizure is a kind of generalized seizure characterized by sudden, brief lapses of consciousness without loss of postural control (1, 2). Typical absence only lasts for a few seconds and consciousness returns suddenly as it was lost, without postictal confusion (3)...

Introduction: The glutamergic receptors affect the synchronization of spike and wave discharges in different animal models of absence seizure. We studied the distribution of a NMDA subtype receptor in CA1 area of the hippocampus.Materials and Methods: Expression of NMDA subreceptor R2, the predominant excitatory neurotransmitter receptor in the brain, was investigated in rats suffering from absence-like seizures.Results: Rats with absence-like seizures exhibited decreased number of these NMDA subreceptors in the hippocampal formation.Conclusion: Changes of expression of these receptors in the hippocampus may be involved in cognition deficits in absence epilepsy.

Introduction: Seizures are symptoms associated with abnormal electrical activity in electroencephalogram (EEG). The present study was designed to determine the effect of absence seizure on heart rate (HR) changes in electrocardiogram (ECG).Methods: HR alterations were recorded simultaneous with spike and wave discharges (SWD) by EEG in 6 WAG/Rij rats as a well characterized and validated genetic animal epilepsy model.Moreover, 6 control rats were used to distinguish the differences of HR changes between various groups. Electrodes were placed on the skull and under the chest skin, minimizing time delay and signal attenuation. HR was calculated by an adaptable algorithm based on continues wavelet transform (CWT) particular for this study. Three main features of HR; minimum, maximum, and mean values were estimated for pre-ictal and ictal intervals for all seizures.Results: ECG beats detected with sensitivity of 99.9% and positive predictability of 99.8% based on CWT. HR deceleration was found in 86% of the seizures. There were statistically significant (P<0.001) reductions of these values from pre-ictal to ictal intervals. Interictal HR acceleration and ictal deceleration were the major feature of alterations and in 23% of seizures, this decrease had priority to the onsets.Discussion: These findings may lead to design a seizure alarm system based on HR and to obtain new insights about sudden unexpected death in epilepsy (SUDEP) phenomenon and side-effects of antiepileptic drugs (AED).

Seizure is the most common neurologic disorder in the pediatric age. Obtaining thorough history and performing complete examination as well as electroencephalography (EEG) are very important in confirming the diagnosis and finding the cause. Epileptiform activity may be enhanced by activating procedures including sleep deprivation. In this study we performed short duration (up to 8 hours) sleep deprivation in 139 children with history of seizure but with normal or non specific awake EEG. We obtained 70% abnormality, 54% of which was of classic pattern of absence (3 Hz spike and slow wave). Most abnormal EEGs belonged to children in the age range of 5-10 yrs. It seems that short duration sleep deprivation is as useful as long duration sleep deprivation.