Elizabeth A. Buffalo, University of Washington

While it has long been recognized that medial temporal lobe structures are important for memory formation, studies in rodents have also identified exquisite spatial representations in these regions in the form of place cells in the hippocampus and grid cells in the entorhinal cortex. Spatial representations entail neural activity that is observed when the rat is in a given physical location, and these representations are thought to form the basis of navigation via path integration. One striking difference between rodents and primates is the way in which information about the external world is gathered. Rodents typically gather information by moving to visit different locations in the environment, sniffing and whisking. By contrast, primates chiefly use eye movements to visually explore an environment, and our visual system allows for inspection of the environment at a distance. In this lecture, I will discuss recent work from my laboratory that has examined neural activity in the hippocampus and adjacent entorhinal cortex in monkeys performing behavioral tasks including free-viewing of complex natural scenes and spatial memory tasks in a virtual environment. These data suggest that spatial representations including place cells, grid cells, border cells, and direction-selective cells can be identified in the primate hippocampal formation even in the absence of physical movement through an environment. I will also discuss new research involving chronic, large-scale recordings throughout the primate brain and other areas of opportunity for future research to further our understanding of mechanisms in the hippocampal formation that support memory formation.