Assessing spatial learning and memory in mice: Classic radial maze versus a new animal-friendly automated radial maze allowing free access and not requiring food deprivation

Joel Kohler; Jie Mei; Stefanie Banneke; York Winter; Matthias Endres; Julius Valentin Emmrich

doi:10.3389/fnbeh.2022.1013624

Assessing spatial learning and memory in mice: Classic radial maze versus a new animal-friendly automated radial maze allowing free access and not requiring food deprivation

Front Behav Neurosci. 2022 Sep 30:16:1013624. doi: 10.3389/fnbeh.2022.1013624. eCollection 2022.

Authors

Joel Kohler¹, Jie Mei^{1

2

3}, Stefanie Banneke⁴, York Winter⁵, Matthias Endres^{1

6

7

8

9

10}, Julius Valentin Emmrich^{1

6

8

11}

Affiliations

¹ Department of Neurology and Experimental Neurology, Neurocure Cluster of Excellence, Charité - Universitätsmedizin Berlin, Berlin, Germany.
² The Brain and Mind Institute, University of Western Ontario, London, ON, Canada.
³ Department of Computer Science, University of Western Ontario, London, ON, Canada.
⁴ German Federal Institute for Risk Assessment (BfR), German Center for the Protection of Laboratory Animals (Bf3R), Berlin, Germany.
⁵ Institute of Biology, Humboldt University, Berlin, Germany.
⁶ Center for Stroke Research, Charité - Universitätsmedizin Berlin, Berlin, Germany.
⁷ Berlin-Brandenburg School for Regenerative Therapies (BSRT), Berlin, Germany.
⁸ Berlin Institute of Health (BIH), Berlin, Germany.
⁹ German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
¹⁰ German Center for Cardiovascular Research (DZHK), Berlin, Germany.
¹¹ Medical Faculty and University Hospital, Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany.

Abstract

The radial arm maze (RAM) is a common behavioral test to quantify spatial learning and memory in rodents. Prior attempts to refine the standard experimental setup have been insufficient. Previously, we demonstrated the feasibility of a fully automated, voluntary, and stress-free eight-arm RAM not requiring food or water deprivation. Here, we compared this newly developed refined RAM to a classic manual experimental setup using 24 female 10-12 weeks old C57BL/6J mice. We used a lipopolysaccharide (LPS)-induced model of systemic inflammation to examine long-term cognitive impairment for up to 13 weeks following LPS injection. Both mazes demonstrated robust spatial learning performance during the working memory paradigm. The refined RAM detected spatial learning and memory deficits among LPS-treated mice in the working memory paradigm, whereas the classic RAM detected spatial learning and memory deficits only in the combined working/reference memory paradigm. In addition, the refined RAM allowed for quantification of an animal's overall exploratory behavior and day/night activity pattern. While our study highlights important aspects of refinement of the new setup, our comparison of methods suggests that both RAMs have their respective merits depending on experimental requirements.

Keywords: LPS (lipopolysaccharide); automation; behavioral test; maze; memory; radial arm maze (RAM); spatial learning.