Evolution of Seizure Patterns in Experimental Epilepsy

Levin, Paul M.; Wyss, F.E.; Scollo-Lavizzari, G; Hess, R

doi:10.1159/000113651

Cited by 8 publications

(5 citation statements)

References 25 publications

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“…Some of this slowing may have been due to the surgical procedure, since it often decreased during the first week of observation. Similar slowing has been discussed by other investigators (Wada and Cornelius, 1960;Levin et al, 1968).…”

Section: Early Electroencephalographic Changes (0-14 Days)supporting

confidence: 89%

“…As indicated, this does not appear to be the case. Rather the progressive involvement of subcortical nuclei appears to be dependent on the sensitivity of each region for the generation of epileptiform activity rather than its synaptic relationship with the primary focus (Walker and Udvarhelyi, 1965;Levin et al, 1968). Unitary recording from neurons in both primary and secondary foci will be required to resolve this question.…”

Section: The Process Of Seizure Spreadmentioning

confidence: 99%

“…In the generalization of epileptiform activity from an experimentally induced cortical seizure focus, cortical and subcortical structures become involved in the spread of abnormal electroencephalographic activity (Morrell, 1959/60;Morrell and Baker, 1961;Ajmone-Marsan, 1963;Wilder and Schmidt, 1965;Proctor et al, 1966;Gloor, 1968;Levin et al, 1968;Wilder et al, 1969;Brazier, 1972;Velasco et al, 1973a,b;Nie et al, 1974;Brown et al, 1980;Babb et al, 1981). Theories on the spread of seizure activity generally assume that the evolution of abnormal neuronal activity within the seizure focus provides an abnormally synchronous input to neurons in other regions of the cerebral cortex and in subcortical nuclei.…”

mentioning

confidence: 99%

“…Wilder et al (1969) noted early epileptiform activity in the red nucleus, putamen, and thalamus of monkeys following cortical lesions produced by a combination of aluminum hydroxide and freezing. While studying the spread of epileptiform activity from subcortical injection sites, Levin et al (1968) observed epileptiform discharges in other regions as early as 1-2 days following the initial injection. In another series of experiments, focal spikes in the homotopic regions of the opposite hemisphere as well as in subcortical structures were observed without the development of spikes in the primary focus in some animals with cryogenic lesions (Proctor et al, 1966).…”

mentioning

confidence: 99%

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The Early Involvement of Subcortical Structures During the Development of a Cortical Seizure Focus

1982

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Cortical surface electrodes and bipolar depth electrodes were implanted stereotaxically in the ventral posterolateral and paracentral thalamic nuclei, amygdala, hippocampus, and putamen in adult cats to determine the progressive involvement of these structures in the generalization of an experimentally induced seizure disorder. Prior to (45-65 days) and following (50-70 days) subpial injection of 0.04 ml of aluminum hydroxide in the sensorimotor cortex, 30 min EEG records were obtained regularly in each animal. At the time of aluminum hydroxide injection, there was no persistent abnormal EEG activity resulting from electrode implantation. In all animals, intermittent slow waves and epileptiform activity appeared in subcortical or extrafocal structures prior to the development of epileptiform activity in the primary focus. These abnormalities were frequently associated with brief clinical seizures and were clearly independent of abnormal activity in the primary focus. Only later in the development of the seizure disorder was activity in the secondary foci observed to be dependent on frequent epileptiform activity in the primary focus. These results demonstrate that multiple, independent foci develop in subcortical structures before the occurrence of a well developed, fully "mature" cortical primary focus.

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Section: Early Electroencephalographic Changes (0-14 Days)supporting

confidence: 89%

Section: The Process Of Seizure Spreadmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The Early Involvement of Subcortical Structures During the Development of a Cortical Seizure Focus

1982

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“…In the animal, deep electrode stud ies do not encounter severe ethical obstacles. We published an observa tion relevant to this problem [Levin et al, 1968]. A cat, during pro longed rage attack, showed bilateral spike discharge in the hippocampi, while surface electrodes disclosed only some slow wave activity.…”

Section: Correlation Of Scalp Eeg and Psychiatric Disturbancementioning

confidence: 99%

Borderline Cases of Petit Mal Status

Hess¹,

Scollo-Lavizzari²,

Wyss³

1971

Eur Neurol

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Six cases of psychotic episodes are described which in some way or another resemble petit mal status, but differ from it in their time courses and in exhibiting focal epileptic discharge besides the bilateral synchronous EEG pattern. These cases are compared with 6 cases more consistent with Lennox’s notion [1960] of petit mal status. Consideration of our own and similar cases from the literature and certain experimental findings lead to the following conclusions: (1) There is no doubt that the bilateral synchronous EEG potentials during so-called ‘centrencephalic’ petit mal status give but a gross and distorted view of the complex electric processes going on in the brain. The existence of different epileptic discharges arising in different brain areas and often mingling into each other is highly probable. (2) In accordance with current neurophysiological theories, the existence of inhibitive processes occurring simultaneously with the various epileptic discharges is accepted. Thus widespread systems of collaborating neurons are left functionally intact. (3) A correlation of level of consciousness with the volumes and locations of involved neurons versus functionally intact neurons is suggested. (4) Evidence for the assumption of epileptic discharge in pararhinal structures during psychotic episodes, often associated with ‘forced normalization’, although not conclusive, must be taken into consideration. (5) Further study of atypical petit mal status might give more detailed information about these questions.

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