CONICET | Buscador de Institutos y Recursos Humanos

Very little information on spatial learning mechanisms is available in amphibians. In the present study three experiments were conducted to determine what strategy is used by the toad Bufo arenarum for spatial learning in a plus-maze situation, using water as reward. Experiment 1 tested the ability to use memorized motor patterns (orientation by a body-centered turn). Experiment 2 tested the ability to use a fixed landmark as guidance (approaching a particular visual cue). Experiment 3 was performed in order to test which of these two strategies was dominant in a maze-learning situation. Animals were trained with a visual cue fixedly located in relation to the body-centered turn; afterwards, a test trial with contradictory information was conducted to reveal which strategy was more relevant to the animals orientation system. Our results demonstrated that toads trained with a combination of a visual cue and an internal self-reference cue preferred the second when the two sources of information were set in conflict (turn response), showing the same pattern response as other mammalian species (e.g., rodents). Several studies with other vertebrates (mammals, birds, reptiles and fish) suggest that these memory processes could have appeared early during phylogenesis. Now amphibians can be included in this group. Thus, comparative research with amphibians could provide interesting insights about the evolutionary and adaptative importance of these strategies in vertebrates. Keywords: spatial learning, orientation, guidance, memory systems, toads