The effects of low frequency and two-pulse stimulation protocols on synaptic transmission in the CA1-subiculum pathway in the anaesthetized rat

The downregulation of synaptic efficacy is referred to as long-term depression (LTD). Recent work has shown that a two-pulse stimulation (TPS) protocol is successful at inducing LTD in vivo in area CA1 of the hippocampus. Here, we examine the ability of two TPS protocols and two low-frequency stimulation (LFS) protocols to induce LTD in the projection from hippocampal area CA1 to the subiculum in the anaesthetized rat. We find no evidence of LTD induction with TPS or LFS protocols. Instead, with three of the protocols (both TPS protocols and 1 Hz LFS), a late-developing potentiation is observed.

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