Figure 3.

Is in vivo LTP observable in vitro? Slices were prepared 24 h following LTP induction, and input–output series were recorded from the tetanized and control hemispheres. (A) There was no observable increase in the medial perforant path fEPSP slope. (B) The population spike was significantly larger in the tetanized hemisphere compared with the control hemisphere. Inset shows representative waveforms from tetanized (arrowhead) and control slices from the same animal. (C) There was a significant correlation between the in vivo population spike LTP and the in vitro population spike amplitude, measured as a ratio of the tetanized to control spike amplitude.