[Facilitation of memory consolidation induced by electrical stimulation of the medial septal nucleus in BALB/c mice (author's transl)].

Sinusoidal (100Hz) electrical stimulation was applied at a weak intensity (7.5microA peak to peak) to the medial septal nucleus after partial acquisition of an appetitive operant conditioning task in a Skinner box. Analysis of performance recorded 24 hrs later during a retention session shows that (i) implantation alone impaired performance; (ii) electrical stimulation applied 30 sec. after the end of the acquisition session improves retention; this facilitatory effect disappears when the treatment is delayed 15 min. Furthermore spectral analysis of hippocampal EEG showed that there was no significant modification of theta rhythms. These results are discussed in relation to studies in the literature which demonstrate that RSA (rhythmical slow activity) is associated with memory-storage processes and our own hypothesis which underlines the importance of activation of septo-hippocampal cholinergic neurons in the early stages of these mnemonic processes.U