The hippocampus, exploratory activity, and spatial memory C. THINUS-BLANC, E. SAVE, M.-C. BUHOT, and

摘要: There is now an impressive set of data which supports the prominent role of the hippocampus in spatial memory. But the hippocampal formation is also involved in exploratory activity, although this function is supported by a much smaller body of studies. Recent psychological studies have now provided direct evidence that exploration and spatial knowledge are closely related to each other by functional, reciprocal links. Hence, it is somewhat surprising that these three poles of interest, the hippocampus, exploration, and spatial knowledge, have not been integrated into a unified, conceptual framework since O'Keefe and Nadel's classic book was published in 1978. It is true that this task is far from easy. In the case of the functional relationship between the hippocampus and spatial cognition, awkward problems may be raised, such as those related to the processing and transformation of information acquired during exploratory activity into spatial knowledge. Exploration is a sensorimotor activity, organized along a body-centred referent, entailing the position of the sensory receptors, the direction of the displacement, gravitational forces, and so on. At the brain level, visual information is projected topographically. In contrast, by their very nature, spatial representations such as cognitive maps must be independent of the subject's current position at a given time; the information is said to be allocentrically organized. So far, a topographical distribution of spatial information has not been discovered in any higher level associative structure involved in spatial mapping and memory. The different levels of brain functioning roughly correspond, at both the …