ウサギ海馬におけるElectroencephalographicスパイク

抄録

electrodes into the hippocampus. The properties of these spikes were studied in the chronic experiment. Furthermore, the electrical activities of the hippocampus and the behavior of the animal were studied in the rabbit in which the theta-input to the hippocampus was partially or totally removed. And the following results were obtained.
1) In either a relaxed or a drowsy state, the EEG spikes appeared in both hippocampi. Very often the EEG spike in one of the hippocampi appeared in synchrony with that in the other. The amplitude and the duration of the EEG spike were 0.5.2mV and 100.300msec, respectively.
2) EEG spikes were depressed when the theta activity was enhanced. It was demonstrated that the depression was due to the changes in the intrinsic hippocampal activities, and not due to the enhancement of the theta activity itself.
3) When the septum was totally destroyed, the hippocampus showed a low voltage fast wave which was further accentuated by sensory stimulations.
4) When the septum was destroyed unilaterally, both hippocampi exhibited the theta activity.
5) As compared with normal animals, those having lesions in the septum or the entorhinal cortex more easily developed seizure discharges. Furthermore the duration of these discharges was longer than that in normal animals.
6) The behavior of the animal without the theta activity following the total destruction of the septum did not show any alteration in the daily life except for a hypersensitivity to sensory stimulations.