The role of vision in the aversion to the open spaces in the elevated plus-maze

Abstract

The elevated plus-maze is one of the most used models to study anxiety, fear and drugs that alter these states. In spite of the apparent simplicity of the model there are several factors that affect the behavior of rats submitted to this test. Besides, the actual environmental stimuli triggering aversion in this model are not known. The present work suggests that, in studies where auditory and olfactory stimuli are controlled, aversion in rats is triggered by vision. The hypothesis advanced is that the mechanisms mediating aversion (and the concomitant emotional states) are triggered by light entering the rats' retina and by images forming in it. In order to fundament these two complementary hypotheses, several experiments are analyzed, the results of which favor one, other or both hypotheses. Finally, results obtained with protein c-Fos staining supply neurofunctional evidence that supports both suggested hypotheses.