SPATIAL AND NONSPATIAL SPONTANEOUS-ALTERNATION AND HIPPOCAMPAL MOSSY FIBER DISTRIBUTION IN 9 INBRED MOUSE STRAINS

Ten male mice from each one of nine inbred strains were tested for spontaneous alternation in a T-maze, which was placed in a spatially richly structured room. Each test consisted of two trials, the first choice to be made was forced, the second one free. By turning the maze 180-degrees between choices during 8 of the 16 tests, 3 variables could be measured: total alternation, spatial alternation, and non-spatial alternation. After Timm's staining, the sizes of the intra- and infrapyramidal mossy fibre terminal fields (iip-MF) were measured. Significant strain differences were found for all variables, but none of the behavioural variables correlated with hippocampal variation. These results disagree with earlier experiments, where large correlations between the iip-MF and spatial working memory were found. Some hypotheses to explain this discrepancy are presented.