查看文章

The present study sought to determine whether post‐training excitotoxic lesions of the dorsal hippocampus would disrupt retention of fear conditioned using a trace procedure. Rats were trained using one of six procedures. Forward trace conditioning consisted of 10 trials in which a 16‐s tone conditional stimulus (CS) was followed by a 28‐s stimulus‐free trace interval and then a mild footshock unconditional stimulus (US). We used two forms of delay conditioning where the tone and footshock co‐terminated. Short delay used a 16‐s tone and long delay used a 46‐s tone. Backward trace conditioning was the same as forward trace, except that the order of the CS and US was reversed. CS‐only and US‐only were similar to forward trace except that the footshock or tone, respectively, was eliminated. One day later, animals received either an N‐methyl‐D‐aspartate (NMDA)‐induced lesion of the dorsal hippocampus …