with metric properties, such as distances, durations and angular deviations. In the third and final step, the observer will be able to use a survey representation of the surroundings, using an allocentric point of view. All in all, the acquisition of cognitive maps is a gradual construction. This kind of knowledge is multimodal in nature and it is built up by different pieces of information coming from different sources that are integrated step by step. Neurological basis Cognitive mapping is believed to largely be a function of the hippocampus. The hippocampus is connected to the rest of the brain in such a way that it is ideal for integrating both spatial and nonspatial information. Connections from the postrhinal cortex and the medial entorhinal cortex provide spatial information to the hippocampus. Connections from the perirhinal cortex and lateral entorhinal cortex provide nonspatial information. The integration of this information in the hippocampus makes the hippocampus a practical location for cognitive mapping, which necessarily involves combining information about an object's location and its other features. O'Keefe and Nadel were the first to outline a relationship between the hippocampus and cognitive mapping. Many additional studies have shown additional evidence that supports this conclusion. Specifically, pyramidal cells (place cells, boundary cells, and grid cells) have been implicated as the neuronal basis for cognitive maps within the hippocampal system. Numerous studies by O'Keefe have implicated the involvement of place cells. Individual place cells within the hippocampus correspond to separate locations in the environment with the sum of all cells contributing to a single map of an entire environment. The strength of the connections between the cells represents the distances between them in the actual environment. The same cells can be used for constructing several environments, though individual cells' relationships to each other may differ on a map by map basis. The possible involvement of place cells in cognitive mapping has been seen in a number of mammalian species, including rats and macaque monkeys. Additionally, in a study of rats by Manns and Eichenbaum, pyramidal cells from within the hippocampus were also involved in representing object location and object identity, indicating their involvement in the creation of cognitive maps. However, there has been some dispute as to whether such studies of mammalian species indicate the presence of a cognitive map and not another, simpler method of determining one's environment. While not located in the hippocampus, grid cells