High frequency oscillations have been proposed as a clinically useful biomarker of seizure generating sites. We used a unique set of human microelectrode array recordings (four patients, 10 seizures), in which propagating seizure wavefronts could be readily identified, to investigate the basis of ictal high frequency activity at the cortical (subdural) surface. Sustained, repetitive transient i...

The release of glutamate from astrocytes activates synchronous slow inward currents (SICs) in hippocampal pyramidal neurons, which are mediated by the NMDA receptor and represent a nonsynaptic mechanism to promote the synchronization of neuronal activity. Two recent studies demonstrate that SICs generate neuronal paroxysmal depolarizations resembling those typical of interictal epileptiform act...

Opiates have complex effects on seizure thresholds as these substances have both anti and proconvulsive actions in the mammalian brain. A reduction of inhibitory synaptic activity or enhancement of excitatory synaptic activity would be expected to trigger a seizure. This study is designed to determine how morphine and naloxone affect seizures induced by a low Mg2+ perfusate in the whole, intact...

Interictal and particularly ictal surface and invasive recordings allow, in most of cases, the precise localization of the cortical area responsible of ictal discharges. During surface Video-EEG the localization could be a little complicated, considering the presence of artefacts, but the occurrence of a low voltage fast activity or a fl attening, permits, coupling with the onset of clinical sy...

High frequency oscillations have been proposed as a clinically useful biomarker of seizure generating sites. We used a unique set of human microelectrode array recordings (four patients, 10 seizures), in which propagating seizure wavefronts could be readily identified, to investigate the basis of ictal high frequency activity at the cortical (subdural) surface. Sustained, repetitive transient i...

We studied four children with diagnosis of absence seizures (generalized primary epilepsy), and with a generalized delta activity on the EEG during clinical attacks provoked by hyperventilation. The lack of ictal generalized spike-and-wave discharges with a frequency of 3 Hz in our patients, makes this an atypical pattern. All children had complete control of their seizures and disappearance of...

A 26-year-old female with intractable epileptic seizures was studied with I-123 iomazenil cerebral benzodiazepine receptor, I-123 IMP inter-ictal and Tc-99m ECD ictal cerebral blood flow SPECT. The ictal cerebral blood flow SPECT indicated the location of the seizures to be in the left temporal lobe, where increased regional cerebral blood flow was noted in marked contrast to the inter-ictal SP...

PURPOSE To investigate the prognostic value of ictal scalp EEG patterns in drug-resistant temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) prior to undergoing temporal lobectomy. METHODS Scalp EEGs of the first seizure recorded during presurgical long-term video-EEG monitoring of 284 patients were reviewed. Patients were divided according to seizure laterality as either ...

Temporal lobe seizures have a significant chance to induce impairment of normal brain functions. Even after the termination of ictal discharges, during the post-ictal period, loss of consciousness, decreased responsiveness or other cognitive dysfunctions can persist. Previous studies have found various anatomical and functional abnormalities accompanying temporal lobe seizures, including an abn...