How to Avoid Going Bump in the Night : Object and Place Representations in the Hippocampus

The cognitive map theory has been a dominant influence over research into hippocampal function since the publication of O'Keefe and Nadel's The Hippocampus as a Cognitive Map in 1978 (now freely available at http://www.cognitivemap.net). The main premise of the theory is articulated in the book's first paragraph: “We shall argue that the hippocampus is the core of a neural memory system, providing an objective spatial framework within which the items and events of an organism's experience are located and interrelated” (O'Keefe and Nadel, 1978). The existence of “place cells” in the hippocampus—principal cells that fire selectively when the animal occupies restricted locations in an environment—is one of the primary pieces of evidence in support of the theory (O'Keefe and Nadel, 1978; Ekstrom et al., 2003). Early investigations of place cells characterized some of these cells as “misplace cells” (...