THE BARNES MAZE TEST: A DRY LAND BEHAVIORAL TEST TO ANALYZE ALZHEIMER’S DISEASE MOUSE MODELS FOR SPATIAL LEARNING DEFICITS

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disease that manifests as memory loss, cognitive dysfunction and dementia. Spatial learning and memory of AD rodent models is often assessed via navigational cues in mazes, most popular are the Morris water maze and the dry-land Barnes maze. Improved performance over sessions or trials is thought to reflect learning and memory. The Barnes maze is considered less stressful compared to water mazes and also useful for rodent models with minor motor deficits. The Barnes maze is a circular platform top with several holes equally spaced around the perimeter edge. Symptomatic animals of two transgenic AD mouse models as well as mice with a scopolamine-induced learning challenge were analyzed in the Barnes maze test using a hippocampal learning protocol. Scopolamine is a competitive antagonist of the muscarinic acetylcholine receptor (mAChR). Systemic application of scopolamine is known to disrupt learning. Barnes maze results were analyzed for escape latency, speed, distance traversed, number of target entries, and the abidance in the target quadrant during the probe trial. Data of different models were compared. Our data show that the dry-land behavioral test apparatus of the Barnes maze is a valuable tool to analyze learning and memory deficits of different rodent AD models. This method might be an effective alternative to the Morris water maze while causing less stress to the animals.