Spike-wave Activity Research Articles

Information processing during two types of EEG activity

A 15-year old girl whose EEG contained frequent bursts of generalized sub-clinical spike-wave activity was examined on a paced serial-choice response task with simultaneous EEG control. The task was carried out at three different speeds and three different information loads. Performance was compared during paroxysms of spike-wave activity and during normal EEG background activity. Four parameters of performance were compared, each parameter being somewhat differently affected by spike-wave activity. “Response ambiguity” was significantly increased in the presence of spike-wave activity, with a corresponding decrease in the amount of “information transmitted”. The “absolute rate” at which information could be transmitted in relation to presentation rate was consequently reduced during spike-wave activity, the effect being most marked at the intermediate speed of presentation (1 signal/2 sec). However, when signals were presented very slowly ( 1 4 sec ) the child's “relative information transmitted” during spike-wave activity approached that achieved under normal background conditions. Thus, accuracy of performance per se is not critically affected by spike-wave; rather it is the rate at which signals can be handled. Spike-wave may therefore be conceptualized as a form of “neural noise” whose effect is to reduce a subject's channel capacity.

Harmful effect of megadoses of vitamins: electroencephalogram abnormalities and seizures induced by intravenous folate in drug-treated epileptics

Folic acid was administered intravenously during constant EEG monitoring to eight epileptic subjects who had received diphenylhydantoin therapy for more than 1 year. Six of the subjects displayed low folate levels by Lactobacillus casei assay in plasma and/or whole blood. Six patients received 75 mg of folate intravenously over a 30-min period without clinical effect of EEG change. One patient exhibited an increase in spike discharges on the EEG in comparison to the baseline pattern, but no clinical change or seizure while receiveing 150 mg of folate in a 30-min period. One patient displayed a 2-sec burst of spike and slow wave activity on the EEG after receiveing 7.2 mg of folate in a 3-min period. A tonic-clonic seizure occured after the infusion of 14.4 mg of folate, and again after infusion of 19.2 mg of folate. There appear to be wide variation in the ability of drug-treated epileptic subjects to tolerate infusions of folic acid. These variations help explain conflicting reports in the literature concerning the effect of folic acid administration on seizure control. Megadoses of folic acid should be employed with great caution in all subjects, but particularly among epileptics. Information is lacking as to whether folate might induce seizures in certain ostensibly normal individuals. It is postulated that folic acid exerts a direct effect among sensitive subjects on existing pathways concerned with the metabolism of folate, histidine, or other important brain metabolites. The mechanism of the anticonvulsant action of diphenylhdantoin remains unknown, but there is considerable evidence to suggest that it interferes with the deamination of histidine.

Lack of levodopa effect on preexisting temporal lobe focus.

Three patients with parkinsonism treated with levodopa had abnormal pre-levodopa and stabilization levodopa electroencephalograms with focal sharp and spikewave activity. There were no seizures and no significant EEG changes with levodopa treatment. This suggests that levodopa may not aggravate a preexisting seizure tendency, as suggested by the EEG.

Visual evoked potentials during experimentally induced spike-wave activity in monkeys

1. 1. Electroretinograms (ERGs) and visual evoked potentials (VEPs) were studied in 16 monkeys both before and after the induction of spike-wave (SW) EEG patterns by the intravenous administration of chlorambucil (13 animals) or by the direct cortical application of conjugated estrogen (3 animals). All of the estrogen preparations and 5 of the chlorambucil animals were studied under gallamine triethiodide paralysis; the other animals were studied under barbiturate anesthesia. 2. 2. In visual system placements (cornea, optic chiasm, optic tract, lateral geniculate nucleus, occipital cortex) there was a reduction or apparent abolition of the ERG of VEP during SW activity. VEPs were rarely seen in non-visual system placements (frontal cortex, parietal cortex, brain-stem reticular formation); averaged potentials from such locations appeared to reflect only increased “noise” during SW activity. 3. 3. When SW activity was confined to frontal cortex (as with the conjugated estrogen preparations) reductions in ERG were less likely to occur. However, generalized SW activity, regardless of how it was produced, was almost invariably accompanied by both VEP and ERG reduction. 4. 4. Reductions in evoked potential amplitudes or complete loss of components tended to be greater in more central placements (LGN, occipital cortex) than in more peripheral placements, and to be more pronounced with more intense visual stimulation. 5. 5. In 2 animals prepared with pre-chiasmal sections of one optic nerve, no substantial reduction in ERG was seen in the eye deprived of connection to the brain, although the usual decrease in amplitude was seen in the contralateral eye. 6. 6. The results were discussed in terms of hypothetical central events in petit mal epilepsy, including the possibility of centrifugal effects upon the retina being transmitted through optic efferent fibers during petit mal convulsive activity.

Panencephalitis Following Measles Vaccination

To the Editor.— We read with interest the report by Landrigan and Witte (223:1459, 1973) concerning the neurologic disorders following live measlesvirus vaccination. According to their records from 1963 through 1971, only one case of suspected subacute sclerosing panencephalitis (SSPE) occurred within one month after live measles-virus vaccination in the United States. Recently, we have observed a child with SSPE who had a previous history of measles-virus vaccination five years earlier. Report of a Case.— A 10-year-old white boy had a stumbling gait and deterioration of school performance. Initial neurological examination revealed slow mentation and mild gait dystonia. Over the next three months, progressive dystonia, myoclonic jerks, and bilateral spasticity, especially of the lower extremities, developed, with progressive intellectual deterioration and feeding difficulty. An electroencephalogram revealed periodic bursts of bilaterally synchronous spike-wave activity. Cerebrospinal fluid (CSF) protein level was 32 mg/100 ml with an elevated gamma globulin fraction of 33%

Seizure occurrence and interspike interval. Telemetered electroencephalogram studies.

The distribution of interictal spikes and the frequency and time of occurrence of seizures were examined from twenty 17 to 72-hour continuous electroencephalograms recorded by radiotelemetry from five patients with epilepsy and behavior disorders. Power spectral analysis of spike incidence over time indicates that there is waxing and waning of interictal spike or spike-wave activity both day and night at periods harmonically related to 90 minutes. Seizure occurrence was noted to be systematically related to this spike cycle. Spontaneous and induced decrements in the mean interictal spike rate were followed by rebound in the abundance and duration of spike bursts. The time of occurrence of clinical seizures appears to be determined by the interaction of interictal spike rate, a 90-minute cyclic suppression of same and sensory, including affective, stimuli.

Some effects of performance variables upon generalized spike-wave activity.

Some effects of performance variables upon generalized spike-wave activity.

INTRARETINAL RESPONSES OF THE CYNAMOLGUS MONKEY TO ELECTRICAL STIMULATION OF THE OPTIC NERVE AND RETINA.

ArticlesINTRARETINAL RESPONSES OF THE CYNAMOLGUS MONKEY TO ELECTRICAL STIMULATION OF THE OPTIC NERVE AND RETINAT. E. Ogden, and K. T. BrownT. E. Ogden, and K. T. BrownPublished Online:01 Jul 1964https://doi.org/10.1152/jn.1964.27.4.682MoreSectionsPDF (4 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByOptic nerve blockade influences the retinal responses to flash in rabbitsVision Research, Vol. 29, No. 8Intraretinal axons of ganglion cells in the Japanese monkey (Macaca fuscata): conduction velocity and diameter distributionNeuroscience Research, Vol. 6, No. 1Visual cortex controls retinal output in the ratBrain Research Bulletin, Vol. 17, No. 1Pretectal neurons project to the salamander retinaNeuroscience Letters, Vol. 24, No. 1Retinal efferents from the pretectal area in the ratBrain Research, Vol. 201, No. 2Absence of efferents to the retina in the frog and toadBrain Research, Vol. 153, No. 2Graded potentials accompanying antidromic invasion of the pigeon retinaVision Research, Vol. 18, No. 10Visual evoked potentials during experimentally induced spike-wave activity in monkeysElectroencephalography and Clinical Neurophysiology, Vol. 35, No. 1The oscillatory waves of the primate electroretinogramVision Research, Vol. 13, No. 6The proximal negative response of the primate retinaVision Research, Vol. 13, No. 4Untersuchungen zur Lokalisierung von Wahrnehmungsprozessen: Figurale Nachwirkungen bei binokularen Wettstreit-Bedingungen25 June 2016 | Perception, Vol. 2, No. 1Cholinergic modulation of single lateral geniculate neurons in the catNeuropharmacology, Vol. 11, No. 2Centrifugal control in the visual system of the pigeonVision Research, Vol. 11Some effects of antidromic stimulation of frog retinal ganglion cellsExperimental Neurology, Vol. 29, No. 2Studies of the optic nerve of the rhesus monkey: Nerve fiber spectrum and physiological propertiesVision Research, Vol. 6, No. 9-10 More from this issue > Volume 27Issue 4July 1964Pages 682-705 https://doi.org/10.1152/jn.1964.27.4.682PubMed14196312History Published online 1 July 1964 Published in print 1 July 1964 Metrics

Relation between the secondary optic fibre system and the centrencephalic system.

AbstractThe existence of a fibre connection from the deep layers of the dorsal lateral geniculate body to the lateral posterior thalamic nucleus has been confirmed with histological methods in the cat. A fibre tract from the lateral posterior thalamic nucles to the ventral anterior thalamic nucleus and to the central lateral thalamic neucleus has been demonstrated.Electrical stimulation of the lateral posterior thalamic nucleus resulted in ipsilateral head movements, loss of posture, jerking and fully developed seizures with loss of bladder control, and with spikewave activity in the EEG in the freely moving cat.Electrical stimulation of anterior thalamic regions at the ventral anterior thalamic nucleus and at the central lateral thalamic nucleus produced only some jerking of the legs, which stopped on termination of the stimulus and was never combined with loss of bladder control.Electrical stimulation of the dorsal lateral geniculate body and of the rostral colliculus and of the nucleus cuneiformus conf...

EEG findings following intravenous injection of diphenhydramine hydrochloride (benadryl R)

A study was made of the effects of intravenously injected diphenhydramine hydrochloride (Benadryl R) on the electroencephalogram. The subjects consisted of: (1) a control series made up of persons without known disease of the central nervous system; (2) patients with known or suspected seizures; (3) patients undergoing electric convulsive therapy. All recordings were taken with the subject in fasting state. Hyperventilation and photic stimulation were used as provocative procedures. There were no changes in the EEGs of the control subjects following intravenous injection of Benadryl R. Patients who had bilaterally synchronous bursts of diffuse slow activity in the pre-Benadryl R record showed a significant reduction of the slow activity after Benadryl R. Patients with focal spiking, or focal spike wave activity, in the pre-Benadryl R record showed a marked increase in the per cent time of the same type of abnormal activity. In addition, Benadryl R was able to provoke focal spike and spike wave activity in patients who had normal records before administration of Benadryl R.

Centrifugal and antidromic effects on ganglion cells of retina.

Centrifugal and antidromic effects on ganglion cells of retina.

Chronic epilepsy in the monkey following multiple intracerebral injection of alumina cream.

Summary1. Chronic experimental epilepsy was induced in 4 of 5 monkeys (Macaca mulatto) by multiple intracerebral injections of alumina cream in the sensori-motor area of one cerebral hemisphere. 2. The early motor convulsive manifestations in the epileptic animals resembled those described in man as epilepsia partialis continua (Koshewnikow). 3. In an additional monkey treated by multiple intracerebral injections of alumina cream into both hemispheres death in status epilepticus occurred 3 weeks after the onset of seizures. 4. EEG's showed marked spike, sharp, and slow wave activity which was most prominent over the injected hemisphere.

On the estimation of cadmium as the oxide

<b>Background</b> The EEG correlate of absence seizures is 3-Hz, generalized spike-wave activity. Depth electrode recordings in animal models suggest that spike-wave activity oscillates within thalamocortical circuits, but the site of the primary abnormality is uncertain. The aim of the present study was to determine whether there is a selective increase in blood flow in the thalamus during absence seizures and, if so, whether it precedes the appearance of spike-wave activity on scalp EEG. <b>Methods</b> Using PET, regional cerebral blood flow (rCBF) was measured in eight patients with idiopathic generalized epilepsy in whom typical absence seizures were induced by voluntary hyperventilation. Each patient was studied up to 12 times, with an intravenous bolus injection of H₂¹⁵O followed by a 90-second scan. The distribution of rCBF during absence seizures and in the 30 seconds before an absence seizure were compared with the distribution of rCBF when absence seizures did not occur. <b>Results</b> There was a mean global 14.9% increase in blood flow in association with typical absence seizures and, on top of the global increase, a focal increase in thalamic blood flow of 3.9 to 7.8%. There were no significant focal changes in rCBF in the 30 seconds before the onset of spike-wave activity on the EEG. <b>Conclusion</b> This study provides evidence for the key role of the thalamus in the pathogene-sis of absence seizures but was unable to show that it is the site of initiation of the seizures.