Topographical memory analyzed in mice using the Hamlet Test, a novel complex maze

Highlights

The Hamlet test is a novel complex environment for testing topographic memory in mice.

Exploration and memory differ in different mouse strains but not gender.

The hippocampus-subiculum-parahippocampal gyrus axis and dopaminergic structures are activated.

Training increased hippocampal neurogenesis (cell proliferation and neuronal maturation).

Topographical disorientation was measured in the Hamlet test using a pharmacological model of Alzheimer's disease.


Abstract

The Hamlet test is an innovative device providing a complex environment for testing topographic memory in mice. Animals were trained in groups for weeks in a small village with a central agora, streets expanding from it towards five functionalized houses, where they can drink, eat, hide, run, interact with a stranger mouse. Memory was tested by depriving mice from water or food and analyzing their ability to locate the Drink/Eat house. Exploration and memory were analysed in different strains, gender, and after different training periods and delays. After 2 weeks training, differences in exploration patterns were observed between strains, but not gender. Neuroanatomical structures activated by training, identified using FosB/ΔFosB immunolabelling, showed an involvement of the hippocampus-subiculum-parahippocampal gyrus axis and dopaminergic structures. Training increased hippocampal neurogenesis (cell proliferation and neuronal maturation) and modified the amnesic efficacy of muscarinic or nicotinic cholinergic antagonists. Moreover, topographical disorientation in Alzheimer's disease was addressed using intracerebroventricular injection of amyloid β25-35 peptide in trained mice. When retested after 7 days, Aβ25-35-treated mice showed memory impairment. The Hamlet test specifically allows analysis of topographical memory in mice, based on complex environment. It offers an innovative tool for various ethological or pharmacological research needs. For instance, it allows to examine topographical disorientation, a warning sign in Alzheimer's disease.

 

Link to the publication :

 

https://www.sciencedirect.com/science/article/pii/S1074742718300340