橋中部・前三叉神経根部位における,切断・局所冷却および電気刺激のウサギ海馬Θリズムに対する影響

抄録

1) Effects of cooling, electrical stimulation and transection at the pontine level upon hippocampal EEG activities were studied in rabbits anesthetized with Nembutal and immobilized with D-tubocurarine.
2) Following a mid-pontine pretrigeminal transection, the hippocampal theta rhythm became higher in frequency and larger in amplitude.
3) Exactly the same results were obtained by means of cooling the mid-pontine region.
4) Exactly the same results could be obtained simply by introducing the cooling needle into the mid-pontine region. This was presumably due to the destruction of a particular nervous tissue by the cooling needle.
5) Electrical stimulation of the mid-pontine region had dual effects on the theta rhythm. One was an amplitude-decreasing effect and the other was a frequency-increasing effect. The former was higher in threshold than the latter.
6) Taken all these results together, it is thought that there exist a theta rhythm-facilitatory system above the mid-pontine level and a theta rhythm-inhibiting system below the mid-pontine level.