Local sleep and spatial memory consolidation during a daytime nap

Quercia, A. 1 , Ferrara, M. . 2 , Committeri, G. 1 , Pizzella, V. 1 & Zappasodi, F. 1

1 Department of neuroscience and imaging University G. d'Annunzio, Institute for Advanced Biomedical Technologies - ITAB, Italy
2 Department of Life, Health and Environmental Sciences, University of L?Aquila, Italy

Sleep-dependent spatial memory consolidation has been established by a large body of evidences. The present study investigates the local learning-dependent changes during a daytime nap after an intensive spatial navigation task and the benefits of sleep on navigation performance both qualitatively and quantitatively.
Eleven healthy males participants (age = 20-30 years, mean ± SD: 24,3±2,45 years; all right-handed, nonsmokers) were asked to learn a three-dimensional virtual (3D) environment, forming a mental representation of it (i.e., cognitive map), in order to travel between different landmarks locations (an hippocampus-dependent strategy) within the virtual environment, as required by the task (performed in the morning). The virtual environment was created by Maze Suite, a 3D software to create environments, with an analysis/mapping tool (Maze Analyzer), that enables to analyze subjects? path, time and units to completion of the maze. Both navigation task and nap (at 2:00 pm) were recorded with high density EEG (128 electrodes, Electrical Geodesics Inc.).
Preliminary results indicate that sleep benefits spatial performance at retest session not only improving time and units to completion of the maze but also enabling the choice of the best paths.