Single session contextual fear conditioning remains dependent on the hippocampus despite an increase in the number of context-shock pairings during learning.

We examined if the strength of contextual fear learning determines whether remote memories become independent of the hippocampus. Rats received 3 or 10 shocks in a single contextual fear conditioning session and then received sham or complete neurotoxic lesions of the hippocampus 7, 50, or 100 days later. Following recovery from surgery, the rats were returned to the conditioning context for a 5-min retention test.