THE NEGATIVE CORRELATION BETWEEN EPSPs AND PSs IN THEEVOKED RESPONSES OF RAT DENTATE GYRUS
齿状回突触后电位和群峰电位的负相关现象

A kind of negative correlation between EPSPs and PSs of the evoked field responses in the dentate gyrus of quiet rest rats was studied. That is, while EPSP declined, PS increased. The ECoG potentials were recorded simultaneously with the evoked potentials. And it was found that during the high voltage slow wave ECoG periods, compared with the low voltage fast wave ECoG periods, PSs increased and EPSPs decreased. It indicated that when the midbrain reticular formation induced cortical desynchronization through the thalamocortical loop, it simultaneously excitated an inhibitory path which acted on the bodies of dentate granule cells and declined the excitability of granule cells. After the injection of Urethane, the negative correlation between EPSPs and PSs were weakened. The negative correlation may be an indication of the activity changes in dentate gyrus during the hypnosis or doze states of rats. So it is significant to study the phenomenon.