A Study on Effect of Hippocampal Dentate Gyrus Lesion on Acquisition and Retention of Working Memory Assessed Using Radial Arm Maze in Wistar Albino Rats

Hippocampal lesion can impair internally cued discrimination in rats. This may be due to either impairment of the perception of the internal cue (subjects do not experience hunger) or its use (the subject experiences hunger but cannot solve some other aspect of the problem). There is strong evidence that hippocampal lesions also impair use of spatial cues by rats. The aim of this study was to investigate the allocentric spatial learning affected by damage to hippocampal Dentate gyrus studied using all arm baited procedure in eight arm radial arm maze, a task involving spatial learning and memory retention. A total of 24 male wistar albino rats were were randomly assigned into four groups with 6 rats in each group. Dentate gyrus lesion was carried out by placing the electrodes stereotaxically into the brain area through the respective holes in the skull. All the behavioral experiments were carried out in three phase’s viz. orientation and training session, learning performance test (retention test) by using radial arm maze. Dentate gyrus lesion by electrolyte & thermo coagulatory method caused significant impairment in the acquisition of spatial task, but not the retention. We conclude that Dentate gyrus is found to be an important area for spatial information coding and processing during the early stage of spatial learning in the rats.