Effect of lesions of the medial pallium on the use of visual cues and turn response in spatial learning in amphibians

MUZIO, R. N., DANERI, M. F., & CASANAVE, E. B.

Almería

Congreso; XXII Meeting of the Spanish Society for Comparative Psychology (SEPC); 2010

Spanish Society for Comparative Psychology (SEPC)

We are analyzing neural mechanisms that rule the spatial learning, looking for common patterns potentially present in a common ancestor to several classes of vertebrates. It is known that the mammalian hippocampus is an important structure involved in spatial learning; but yet, its function in other vertebrates such as amphibians is unknown. Amphibians have a neural area supposed to be homologous to the mammalian hippocampus, the medial pallium. The main goal of the present work was to study the role of this structure in two simple spatial orientation tasks. Partially dehydrated toads (Bufo arenarum) were divided in 3 groups: Medial pallium lesioned, Intact and Sham controls. Animals were daily trained in a plus maze (3 trials per session) for the acquisition of two basic spatial orientation strategies to reach a container full of water: use of a visual cue (Experiment 1), or the use of a turn response (Experiment 2). Animals of control groups reached the goal in both task, but the lesioned animals never showed spatial orientation. Our results suggest that amphibian medial pallium is involved in basic spatial orientation strategies, showing furthermore that hippocampus and medial pallium are structures with a partial functional equivalence.