Non-spatial water radial-arm maze learning in mice

Recently, we published a method for examining working and reference memory in mice using a spatial version of the water radial-arm maze. Here we descr ibe a non-spatial version of the same maze. BXSB mice were able to learn th e maze as shown by the decrease in the number of working and reference memo ry errors over sessions. This maze was used to examine learning differences between males and females and between mice with misplaced clusters of neur ons in layer I of cortex (ectopias) and those without. In a prior study usi ng the spatial version of the water radial-arm maze, male BXSB mice had poo rer working memory than females during the acquisition phase. Similarly, in this study male BXSB mice demonstrated impaired working memory during the asymptotic phase of non-spatial radial-arm maze learning. Two prior studies showed that mice with neocortical ectopias demonstrated working memory imp airments compared to non-ectopic littermates in the spatial version of the water radial-arm maze. Contrary to this, in the non-spatial radial-arm maze used here, ectopic mice were not impaired in working memory and showed bet ter memory when the working memory 'load' was the highest. Overall, both ve rsions of the maze can be useful tools to assess spatial and non-spatial wo rking and reference memory in mice. (C) 2000 Elsevier Science B.V. All righ ts reserved.