XXXX induced by @entity116 toxin: a longitudinal electroencephalographic study.

@entity410 @entity19 @entity302 @entity35 @entity116
An @entity302 was induced in @entity35 by injection of @entity116 toxin (approximately 10 @entity19 LD50) unilaterally into the hippocampus. Continuous EEG records were obtained from implanted hippocampal electrodes for periods of 4-7 weeks in 14 @entity35 . In a pilot study of two of these @entity35 , three more recording electrodes were placed in other brain areas. Six of the @entity35 (including the latter two) were simultaneously filmed using time-lapse videorecording, and the relationships between EEG events and overt motor fits were assessed using a split-screen video monitoring system. Characteristic peaks and troughs in the numbers of overt fits occurring each day were noted in all the @entity35 that were filmed, and less marked peaks occurred in the numbers of hippocampal @entity410 discharges. At the start of the syndrome, @entity410 discharges occurred without accompanying fits; then overt fits occurred with some of the discharges; later the animals stopped having fits but @entity410 discharges continued to occur alone for several weeks. Fits only occurred with longer @entity410 discharges (more than approximately 30 s), but not all longer @entity410 were associated with fits. Whether or not a hippocampal @entity410 discharge leads to a motor fit appears to depend not on the nature of the electrical activity in the hippocampus but probably on the properties of areas, such as the cingulate gyrus, to which the @entity410 activity may spread. Large @entity302 occurred throughout the syndrome, and their frequency was often increased for some minutes after a @entity410 discharge. While there was an overall correlation between the number of fits and the number of @entity410 discharges occurring during the entire syndrome, within relatively brief periods this relation was not consistent. The occurrence of motor fits was often associated with a decrease in @entity410 discharge frequency. In the four @entity35 with bilateral electrodes, some independent EEG activity was observed in the uninjected hippocampus.
