Frontiers in Behavioral Neuroscience (Dec 2012)
Hippocampus-dependent place learning enables spatial flexibility in mice
Abstract
Spatial navigation is a fundamental capability necessary in everyday life to locate food, social partners and shelter. It results from two very different strategies: (i) place learning which enables for flexible way finding and (ii) response learning that leads to a more rigid ‘route following’. Despite the importance of knockout techniques that are only available in mice, little is known about mice’ flexibility in spatial navigation tasks.Here we demonstrate for C57BL6/N mice in a water-cross maze that only place learning enables spatial flexibility and relearning of a platform position, whereas response learning does not. This capability depends on an intact hippocampal formation, since hippocampus lesions by ibotenic acid disrupted relearning. In vivo manganese-enhanced magnetic resonance imaging revealed a volume loss of ≥ 60% of the hippocampus as a critical threshold for relearning impairments. In particular the changes in the left ventral hippocampus were indicative of relearning deficits.In summary, our findings establish the importance of hippocampus-dependent place learning for spatial flexibility and provide a first systematic analysis on spatial flexibility in mice.
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