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The Barnes maze offers advantages for cognitive aging studies, because of its relatively unstressful design and its modest physical demands. The authors therefore undertook a detailed chronological investigation of performance against age, for female Sprague-Dawley and male and female Dark Agouti rats. The trial duration was 10 days. Rats were tested at 6, 11, 14, 17, 20, and 26 months of age, but individual rats were tested at one age only. At 6 months of age, all rats reached the criterion. Sprague-Dawley rats performed best at this age. Impairment began at 14 months in Dark Agouti rats and continued to increase up to 26 months of age. Impairment was greater in Dark Agouti than Sprague- Dawley rats and was greater in females than males. At 26 months, 70% of Sprague-Dawley females reached criterion; of the Dark Agoutis, only 33% of females and 57% of males reached criterion. This study confirms the utility of the Barnes maze as a robust vehicle in aged rats. It also highlights major performance differences between strains and genders in aging rats. [ABSTRACT FROM AUTHOR]

V. V. Pravosudov, P. Lavenex, and A. Omanska (2005) reported that undernutrition in the first few weeks' posthatching leads to lower mean hippocampus volumes in adult Western scrub jays (Aphelocoma californica) and to poorer performance on spatial memory tasks. Together with prior work on the effects of poor nutrition on the development of the song system in songbirds, these results fit reasonably well with the view that natural selection determines priorities for investment in the development of neural structures. What seems somewhat anomalous under this view is that undernutrition did not affect the development of color association abilities in scrub jays. This work sets the stage for future comparative research on adaptive priorities in the development of brain and behavior. [ABSTRACT FROM AUTHOR]

Development rates vary among individuals, often as a result of direct competition for food. Survival of young might depend on their learning abilities, but it remains unclear whether learning abilities are affected by nutrition during development. The authors demonstrated that compared with controls, 1-year-old Western scrub jays (Aphelocoma californica) that experienced nutritional deficits during early posthatching development had smaller hippocampi with fewer neurons and performed worse in a cache recovery task and in a spatial version of an associative learning task. In contrast, performance of nutritionally deprived birds was similar to that of controls in 2 color versions of an associative learning task. These findings suggest that nutritional deficits during early development have long-term consequences for hippocampal structure and spatial memory, which, in turn, are likely to have a strong impact on animals' future fitness. [ABSTRACT FROM AUTHOR]