Search Strategies Used byAPPTransgenic Mice During Navigation in the Morris Water Maze

Abstract

TgCRND8 mice represent a transgenic mouse model of Alzheimer's disease, with onset of cognitive impairment and increasing amyloid-␤ plaques in their brains at 12 weeks of age. In this study, the spatial memory in 25-to 30-week-old TgCRND8 mice was analyzed in two reference and one working memory Morris water maze (MWM) tests. In reference memory tests, the mice were trained to escape to a hidden platform, which in one version of the test was marked by a visual cue. In the working memory test, the hidden platform was moved daily to different locations. The TgCRND8 mice were impaired in reference memory when trained in a hidden platform test. However, the mice developed spatial memory comparable to non-Tg littermates in a cued reference memory test. The mice showed also an impairment in spatial working memory. Analysis of search paths revealed that in contrast to non-Tg littermates, TgCRND8 mice did not use spatial strategies during their navigation. Instead, they learned to locate an escape platform using a nonspatial, chaining strategy. The study showed that (1) the impairment in the reference memory of TgCRND8 mice was reduced when a hidden platform was cued, and that (2) both working and reference memory systems of TgCRND8 mice, but not (3) the plasticity of choice between search strategies, are compromised by the transgene-induced pathology.

Spatial and nonspatial escape strategies in the Barnes maze

“…Specifically, inbred wild-type mice with excitotoxic or seizure-induced lesions of the hippocampus or entorhinal cortex are often impaired on both in the hidden-and visible-platform versions of the water maze (Hardman et al 1997;Logue et al 1997;Lipp and Wolfer 1998;Mohajeri et al 2003Mohajeri et al , 2004Lipp et al 2004). It is not clear from these studies whether hippocampal insults impair the ability to make the association between the escape platform and the discrete cue, or whether mice attempt to use a spatial strategy to solve the cued-platform version and are unable because of the lesion Hauben et al 1999;Janus 2004). Some deficits following large lesions may result from damage to association areas within the hippocampal formation .…”

Age-Dependent Neurofibrillary Tangle Formation, Neuron Loss, and Memory Impairment in a Mouse Model of Human Tauopathy (P301L)

“…8 A, B) was not as a result of a motor disability, we examined swim speed at Ն4 months. Data from hidden platform and probe trials revealed faster swim speeds in taupositive versus tau-negative mice at 4 -7 months of age, possibly reflecting a difference in search strategy (Janus, 2004). Mean swim speeds were lower in 9.5-month-old rTg(tau P301L )4510 mice compared with controls.…”

A complex dietary supplement augments spatial learning, brain mass, and mitochondrial electron transport chain activity in aging mice

“…In other studies, some mice employ a search strategy where they circle the pool at a distance from the wall that ensures finding the platform (chaining) (Janus 2004;Patil et al 2009). With further training, Fig.…”