Low-frequency stimulation does not readily cause long-term depression or depotentiation in the dentate gyrus of awake rats.

The ability of low-frequency stimulation (LFS) to induce either long-term depression (LTD) or depotentiation was assessed for perforant path synapses in the dentate gyrus of awake, adult rats. Neither LFS at 1 Hz (100 or 900 pulses) nor LFS at 3 Hz (900 pulses) was sufficient to produce either LTD or depotentiation. LFS at 3 Hz did produce a transient response depression of previously potentiated synapses, but this lasted less than 24 h and was secondary to seizure-like afterdischarges. We conclude that the LFS protocols so effective at eliciting LTD and depotentiation in area CA1 are ineffective for perforant path synapses in the dentate gyrus.