Fig. 9.

Landmarks promote efficient spatial search and sensory sampling. A: the visit density maps indicate that the Landmark group searched closer to the missing food location during Probe trials than the None group. Landmark group animals were trained with four landmarks presented at fixed locations; None group animals were trained without any landmarks. Four animals were pooled in each group. The normalization was done separately in each group. B: the search area fraction demonstrates that the group trained with stable landmarks has the most focused search area around the food location. C: two-dimensional (2D) Gaussian function (indicated by the contour plot) was fitted to the visit density map to estimate the center (blue circle) and spread of the search locations. D: the mean estimation error quantifies the distance between the missing food location and the center of the 2D Gaussian fitting. Landmark group showed lower estimation errors than the None group. The spread of search is quantified by the SD of the 2D Gaussian fit, and this was also lower in the Landmark group (circles indicate different individuals). E: sampling density maps indicate that the Landmark group increased their sampling density near the missing-food location, while the None group did not. F: bar plot (mean ± SE) indicates the sampling density near the missing-food location (<15 cm, indicated by the black circles in E). Landmark group had significantly higher sampling density than the None group in Probe trials. *P < 0.05. **P < 0.01. ***P < 0.001.