Exploratory patterns of rats on a complex maze provide evidence for topological coding

Rats' exploratory patterns on a complex elevated maze were analyzed in both light and dark conditions. Rats were less active in the light than in the dark. In the light, they spent more time exploring the outer areas of the m aze than the inner areas whereas exploration of both regions was similar in the dark. In both light and dark, rats spent more time investigating choic e points (which provided multiple directions for movements) than runways th at allowed only simple movements. In addition, choice points that provided more connections with other distant places were associated with more explor ation. While such effects: might be the result of stimulus-seeking of dista nt information in the light, increased exploration times in the dark presum ably reflect the processing of local information associated with the maze c onnectivity. These results suggest that exploratory patterns in the dark re flect processing of the topological structure of the maze. (C) 2001 Elsevie r Science B.V. All rights reserved.