Classic conditioning in aged rabbits: delay, trace, and long-delay conditioning.
Young (0.5 years) and aged (2+, 3+, and 4+ years) rabbits underwent acquisition of the classically conditioned nictitating membrane response in a delay (500-ms conditioned stimulus [CS], 400-ms interstimulus interval [ISI]), long-delay (1,000-ms CS, 900-ms ISI), or trace (500-ms CS, 400-ms stimulus-free period) paradigm. Collapsing across age groups, there is a general tendency for animals to acquire trace conditioning more slowly than delay conditioning. Collapsing across conditioning paradigms, there is a general tendency for aged animals to acquire more slowly than younger animals. Of greater significance, however, are the age differences in the different conditioning paradigms. In the delay and long-delay paradigms, significant conditioning deficits first appeared in the 4(+)-year-old group. In the trace conditioning paradigm, significant conditioning deficits became apparent in the 2(+)-year-old animals.
Solomon
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Department of Psychology and Program in Neuroscience, Williams College, Williamstown, Massachusetts 01267, USA. psolomon@williams.edu
Groccia-Ellison
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D000375:Aging; D000818:Animals; D001767:Blinking / Q000502:physiology*; D003214:Conditioning, Classical; D009541:Nictitating Membrane / Q000502:physiology; D011817:Rabbits