Synaptic plasticity in the hippocampus of awake C57BL/6 and DBA/2 mice: Interstrain differences and parallels with behavior

C57BL/6 mice consistently outperform DBA/2 mice in a range of hippocampal‐dependent spatial learning behaviors. We recorded evoked responses from the dentate gyrus of awake, freely‐moving mice and measured synaptic plasticity (LTP) and performance in a hippocampal‐dependent task in individual animals from these two inbred strains. Spatial alternation tasks confirmed the behavioral divergence between the two strains, with C57BL/6 mice demonstrating more robust alternation than DBA/2 mice. Recording changes in field potentials in the dentate gyrus following three different high‐frequency stimulation paradigms in the same groups of animals revealed differences in neural plasticity: both strains were able to support long‐term potentiation (LTP) at perforant path synapses, but brief high‐frequency stimulation induced larger and longer potentiation of the population spike in C57BL/6 than in DBA/2 mice. This greater propensity for population‐spike potentiation in the strain that performed better in a hippocampal‐dependent task is in accord with the different neurochemical profiles of C57BL/6 and DBA/2 mice. Hippocampus 2001;11:391–396. © 2001 Wiley‐Liss, Inc.