Two complementary circuits for spatial navigation in mouse: evidence from Fos mapping

Abstract

We designed and implemented a novel spatial behavioral protocol based on the figure 8 maze paradigm. This solution employs a fully automated closed-loop system using visual contexts for guiding behavior. It allows high throughput testing of large cohorts of animals. This automated approach highly reduces the effect of stress, but also eliminates the influence of rule learning and the involvement of working memory. Here, we show that training mice in the apparatus leads to change in strategy from internal tendency to alternate into navigation based exclusively on visual cues. This effect could be achieved using two different protocols: prolonged alternation training, or a flexible protocol with unpredictable turn succession. We provide evidence of opposing levels of engagement of hippocampus and retrosplenial cortex after training mice in these two different regimens. This supports the hypothesis of the existence of parallel circuits supporting navigation, one based on the well described hippocampal representation, and another, RSC-dependent.