Further studies of the role of hippocampal synaptic plasticity in spatial learning: is hippocampal LTP a mechanism for automatically recording attended experience?

Rats trained as normal animals on a delayed matching-to-place task until they were fully familiar with the environment and the strategy required for effective performance were treated with a CSF or D-AP5 at a dose shown to be sufficient to block LTP in vivo. A striking delay-dependent impairment was observed in the AP5-treated animals. These findings indicate that 1-trial event memory depends on NMDA receptors.