The Modulation of Medial Septal Nucleus on Learning-Dependent Long-Term Potentiation in The Rat Dentate Gyrus

Population Spike (PS) elicited by perforant path stimulation in the dentate gyrus (DG) of freely moving rats was recorded.Rats were trained on discrimination learning.The results were as follows:(1)High-frequency stimulation (HFS) of the medial septal nucleus (MS) temporarily caused a suppression of PS in DG;(2) HFS of MS following daily training session caused a significant suppression of the development of learning-dependent long-term potentiation (LDLTP),and correspondingly,a prevention of the acquisition of discriminative responding;(3)HFS of MS resulted in a significant decrease (P<0.01) of the maximal level of the potentiation of PS amplitude.These results suggest that MS exerts an inhibitory modulated effects on LDLTP in DG,which mainly affects the development of LDLTP.