ANALYSIS OF THE DECREMENTAL NATURE OF LTP IN THE DENTATE GYRUS

The persistence of long-term potentiation (LTP) in the dentate gyrus w as compared for two tetanization protocols: 50 trains on one day, or 5 0 trains on 5 consecutive days. LTP induction was significantly greate r in the 250 train condition, but the LTP decay rate over weeks was si milar between conditions. The decay of LTP could not be accounted for by deterioration of the preparation. Successive days of stimulation ca used repetitive induction of immediate early genes, but did not prolon g LTP, suggesting that either the effects of gene expression on LTP st abilization had saturated, or that these genes play other roles in syn aptic plasticity.