Cholinergic mediation of spatial memory in the preweanling rat: Application of the radial arm maze paradigm.

In 2 experiments with 70 Sprague-Dawley rats, Ss were trained and tested in the maze from 16 to 25 days of age. Results show that Ss that received training performed significantly better than those naive to the task and better than chance, which suggests an early capacity for this type of learning. To distinguish between the working and the reference memory components of the task, a modification of the basic radial arm maze paradigm was used. Ss trained from 16 days received drug injections of saline, methscopolamine bromide, scopolamine hydrobromide, or arecoline hydrobromide prior to testing at 25 days. Results indicate that central cholinergic antagonism severely impaired working memory while sparing reference memory. This finding is consistent with a role for acetylcholine in adult learning and memory, specifically in working memory. Findings document that (a) the radial-arm-maze paradigm can be used effectively for the developmental study of learning and memory in the rat and (b) cholinergic system(s) mediates working memory at an early age. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)