Conditional learning in aged rats: evidence of hippocampal and prefrontal cortex impairment.
Groups of normal old rats and young adult rats were administered a test of conditional discrimination learning in which different visual stimuli were associated with responses to different levers. Initially, rats were tested in a zero-delay condition in which they selected their responses in the presence of the conditional stimuli. They were later tested at 5- and 15-s delays between stimulus presentation and the appearance of the levers. Old rats were impaired in learning the basic conditional discrimination, a test thought to be sensitive to frontal lobe dysfunction. Age differences increased with the length of the interval, revealing a time-dependent memory loss that was attributed to impaired hippocampal function.
Winocur
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Department of Psychology, Trent University, Peterborough, Ontario, Canada.
D000375:Aging / Q000502:physiology*; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology*; D004192:Discrimination, Psychological / Q000187:drug effects; D005625:Frontal Lobe / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D008297:Male; D051381:Rats; D012055:Reinforcement Schedule