Renovating the Barnes maze for mouse models of Dementia with STARR FIELD: A 4-day protocol that probes learning rate, retention and cognitive flexibility.

Land-based mazes that require spatial cues to identify the location of a hiding-place are a low-stress method to evaluate learning rate and memory retention in mice. One version, the Barnes maze, allows quantification of naturalistic exploratory behaviors not evident in water-based tasks. As the task relies on innate behaviors, it does not require overtraining, making it more feasible to examine early learning and non-memory executive functions that are characteristic of some non-amnestic dementias. However, because it is difficult to hide odor cues in the traditional version of the maze, learning rate during individual trials can be difficult to interpret. We designed and tested the use of 3D-printed escape shuttles that can be made in duplicate, as well as a docking tunnel that allows mice to self-exit the maze to improve reproducibility and limit experimenter influence. In combination with maze turning and escape tunnel caps, we show our shuttles mitigate the possibility of undesired cues. We then compare use of our 4-day protocol across several mouse models of cognitive impairment. We demonstrate an additional stage, the STARR protocol (Spatial Training and Rapid Reversal), to better challenge executive functions such as working memory and behavioral flexibility. We examine commonly used outcome measures across mice with and without access to spatial cues, as well as across mouse models of cognitive impairment to demonstrate the use of our 4-day protocol. Overall, this protocol provides detailed instructions to build and perform a robust spatial maze that can help expand the range of deficits identified. Our findings will aid in interpretation of traditional protocols, as well as provide an updated method to screen for both amnestic and non-amnestic cognitive changes.