Coding of spatio-temporal attributes: the roles of age and enriched environment

Abstract

Spatio-temporal attributes are the abilities to remember the position and location of objects in space which may include orientation, direction and distance. Such abilities have been studied in neurological impaired samples. However, enough studies on the roles of cognitive reserve like age and environmental enrichment on coding of spatial abilities in normal samples have been understudied. Similarly, preclinical behavioral protocols of working memory for spatial abilities have been equally sparse. The present study was to examine the effects of age and environmental enrichment on coding of spatial abilities in long evan rats. Conversely, the present study further examined the utility of the training protocol used in the study for assessment of spatio-temporal working memory in preclinical trials. Twenty six naive male long evan rats between the ages of 9-21 months, weighing between 200-400g were use for the study. They were divided into 3 groups: enriched young adults, non-enriched young adults and non-enriched older adults. The Royal Institute of Psychologists Maze Box patterned after that described by Olton and Samuelson (1976) was used while the training procedure was adopted from Kesner (1985) model of amnesic study in rats. The findings showed no significant differences among the groups on all trials. However, overall progress in performance showed that enriched young adults continued to improve as the trials progress, while the non-enriched older adults  showed some decrements from the third day of the trial. On the other hand, significant inter-trial correlations were found between each trial per day and total trial per day showing some level of test-retest reliability of the training protocol. Conversely, between trials improvement were found in performance of the subjects each day showing that learning and memory truly took place. The discussions of the study were on the possible reasons for such non significant differences in performance despite contrary past research studies.

Keywords: Spatio-temporal, learning, working memory, Long evan rats, radial arm maze