Landmark recognition in XXXX : spared implicit memory for objects relevant for navigation.

@entity1 @entity2730 @entity195
BACKGROUND: In spatial navigation, landmark recognition is crucial. Specifically, memory for objects placed at decision points on a route is relevant. Previous fMRI research in healthy adults showed higher medial-temporal lobe (MTL) activation for objects placed at decision points compared to non-decision points, even at an implicit level. Since there is evidence that implicit learning is intact in @entity2730 @entity1 , the current study examined memory for objects relevant for navigation in @entity1 with @entity195 ( @entity195 ). METHODOLOGY/PRINCIPAL FINDINGS: 21 @entity195 @entity1 participated with MTL atrophy assessed on MRI (mean MMSE=21.2, SD=4.0), as well as 20 age- and education-matched non-demented controls. All @entity1 watched a 5-min video showing a route through a virtual museum with 20 objects placed at intersections (decision points) and 20 at simple turns (non-decision points). The instruction was to pay attention to the toys (half of the objects) for which they were supposedly tested later. Subsequently, a recognition test followed with the 40 previously presented objects among 40 distracter items (both toys and non-toys). Results showed a better performance for the non-toy objects placed at decision points than non-decision points, both for @entity195 @entity1 and controls. CONCLUSION/SIGNIFICANCE: Our findings indicate that @entity195 @entity1 with MTL damage have implicit memory for object information relevant for navigation. No decision point effect was found for the attended items. Possibly, focusing attention on the items occurred at the cost of the context information in @entity195 , whereas the controls performed at an optimal level due to intact memory function.
