Spatial memory over long retention intervals: nonmemorial factors are not necessary for accurate performance on the radial-arm maze by rats.

A. Markowska, O. Buresová, and J. Bures (1983, Behavioral and Neural Biology, 38, 97-112) argued that the apparent persistence of accurate spatial working memory over delays of several hours arises from the formation of response strategies and the use of olfactory stimuli that develop with extended training at long delays. To test this explanation rats with extensive prior training at long delays were forced to enter the first four arms in a random order. On test days, the maze was rotated 180 degrees during the 2-h retention interval to determine whether the rats were using intramaze or extramaze (i.e., spatial) cues to guide their choices. On both rotation and control days, postdelay choices were spatially guided, averaging over 90% correct. Accurate spatial working memory at long delays is a reproducible phenomenon and does not appear to result from nonmemorial artifacts.