No apparent age differences in hippocampal theta frequency in rabbits aged 3-50 months.

Evidence has accumulated to suggest that the hippocampus is impaired by aging processes. Hippocampal EEG was examined in 3- to 50-month-old rabbits before they were classically conditioned in the trace paradigm. Hippocampal EEG was recorded from electrodes implanted proximal to the pyramidal layer of CA1. There were no age differences in hippocampal EEG frequency over the age range of 3-50 months. Animals were subsequently trained in a trace classical conditioning paradigm, and there were large age differences in acquisition and retention. Results suggest that rabbits as young as 2.5 years old show behavioral deficits in conditioning, but hippocampal EEG frequency was not correlated with the age differences in behavior.