The effects of delays and interference on spatial working memory in differentially reared rats

This Thesis investigated the effects of three forms of differential housing, namely Isolated (IC), Enriched (EC), and Long­ term Enriched (LTE), on short-term spatial working memory, by using a series of delays and two forms of explicit interference to test retention of the basic non-matching-to-sample task. Experiment 1 investigated the behaviour of two groups of rats, IC and EC, which had been differentially housed from 35 days of age and found that the longer the delay, the more performance was impaired across both housing groups. The Maze interference was found to significantly affect performance, but the Interference Box did not, indicating that the nature of the interfering task was of prime importance. No effects for differential housing emerged. Experiment 2 investigated the behaviour of three experimental groups, IC, EC and LTE, which had been differentially housed from 21 days, and, likewise, found that the delays significantly affected performance, as did both forms of Interference. Analysis of the behaviour within the Box Interference found that Experiment 2 animals exhibited more activity, giving one possible explanation for this difference in behaviour between the two experiments. An open field activity observation was also done. The results of these experiments did not support the notion that an enriching environment produces superior cognitive capacity