One-shot spatial memory task on the event arena for mice. (a) Event arena for one-shot spatial memory task. The event arena during a daily choice phase. Five sand wells are open but only one contains the reward pellets. All open sand wells contain several pellets that are inaccessible to the mouse in order to control for olfactory artefacts. (b) Daily spatial memory performance (errors). Every day mice have two trials to encode the new sand well location, followed by a choice phase. They quickly reach a stable performance level of less than one error (with two errors being the chance level). (c) Novelty-induced enhancement of memory persistence. Critical sessions involve one sample trial followed by an unrewarded probe test 24 h later. 5 min exploration of a novel environment 30 min after encoding results in enhanced persistence of one-shot spatial memory, as demonstrated by increased dig time in the correct location. (d) Prediction of memory enhancement by optogenetic stimulation of catecholaminergic nuclei. We predict that photoactivation of DA cells of the VTA or DA-releasing NA cells of LC in TH-Cre mice injected with Cre-dependent ChR2 virus (AAV-Flex-ChR2) after weak memory encoding will result in enhancement of memory persistence that mimics the novelty effect. Error bars, s.e.m; dotted lines, chance level.
OF MICE AND SAND -REVISED- Cheat
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