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AN ELECTHOGHAPHIC STUDY ON THE CHANGES OF EXPERIMENTAL SEIZURE DISCHARGES INDUCED BY LOCAL APPLICATION OF CONVULSANTS IN THE NEOCORTEX AND LIMBIC STRUCTURES DURING NATURAL SLEEP IN THE CAT (THE STUDY ON SLEEP, II)
Author(s) -
Okuma Teruo,
Hayashi Akio,
Fujimori Masamoto
Publication year - 1964
Publication title -
psychiatry and clinical neurosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.609
H-Index - 74
eISSN - 1440-1819
pISSN - 1323-1316
DOI - 10.1111/j.1440-1819.1964.tb00012.x
Subject(s) - convulsant , strychnine , neocortex , hippocampus , convulsants , sleep (system call) , amygdala , anesthesia , neuroscience , slow wave sleep , psychology , pentylenetetrazol , sleep induction , chemistry , epilepsy , electroencephalography , medicine , melatonin , anticonvulsant , receptor , computer science , operating system
S ummary (1) The change of experimental seizure discharges in the neocortex, amygdala and hippocampus induced by the application of convulsant drugs such as strychnine were observed in chronically implanted cats during different stages of their natural sleep, including the period of activated sleep. (2) When the effect of strychnine was strong, the neocortical seizure discharges showed a slight enhancement during the spindle and slow wave stages and a marked enhancement during the activated sleep stage. The enhancement of spikes was also observed when the animal was excited. When the effect of strychnine was intermediate, the change in the number of seizure discharges during different stages of sleep was less remarkable. The weak strychnine discharges on the contrary, was suppressed during both the arousal and activated sleep stages while it was enhanced during the spindle and slow wave stages. (3) The neocortical strychnine spikes showed a marked enhancement concurrent with the rapid eye movements during the activated sleep. The seizure discharge sometimes showed a sustained high frequency burst during the activated sleep period and occasionally developed into a generalized seizure. (4) When the effect of the convulsant drug was strong the experimental seizure discharge in the amygdala and hippocampus, remained almost uninfluenced during the different stages of sleep or showed a slight enhancement during both the excited state and activated sleep stage. The weaker seizure discharges in those structures showed enhancement during the spindle and slow wave stages but were suppressed almost completely during both the arousal and activated sleep stages. Thus, no significant difference was found between the neocortical and the limbic structures, as far as the changes of the firing pattern of seizure discharges during a cycle of sleep was concerned. (5) These findings seemed to confirm the authors' previous assumption that the activity level of a cats brain during activated sleep might be comparable to those of the arousal stage. Possible mechanisms of the changes of the experimental seizure discharges during different stages of sleep, particularly during the activated sleep, were discussed.