Animal models of declining memory in the aged: short-term and spatial memory in the aged rat.

Short-term and spatial memory were studied in Fischer 344 rats ranging in age from 6 to 26 months of age. Spatial memory, as measured by performance in an 8-armed radial maze, declined gradually with age. In contrast, short-term memory, as measured by retention of previous choices in the spatial maze over short intervals and performance on a modified form of Konorski's discriminated delayed response task, did not decline differentially as a function of age. These findings may be comparable to those obtained in the aged human, who also show marked deficits in spatial memory and little change in primary memory under appropriate test conditions.