of reduced platform interval lighting and pseudorandom platform positioning

Two procedural components of place navigation training in the Morris (1981) water task were studied. Specifically, rats were required to escape onto a submerged (hidden) platform located in either a fixed or a pseudorandomlyvariedposition throughout training; Following escape, the animals were either given unrestricted visualaccess to the extramaze-environmentfor the dura-tion of the platform interval (45 see) or denied this opportunity through- reduced-laboratory illu-mination. The results of the experiment indicate that (1)pseudorandom platform positioning primarily attenuated the rats ’ rate of acquisitionrather than postasymptotic escapeperformance, and (2) visibility of distal cues from the goal location during training was not necessary for ap-propriate place navigation tooccur. Further evidence obtained from a transfer test given on the final day of training suggests that rats trained with a pseudorandomly positioned platform may have acquired specific knowledge of multiple goal locations. These findingsprovide further sup-port for the claim that rats acquire distal cue information primarily-while-en-route to the platform. The water-maze tasks developed by Morris (1981, 1984) have been used extensively to investigate the neuro-biological basesof spatial learning in the rat (e.g., Hagen