Memory System Neurons Represent Gaze Position and the Visual World

The entorhinal cortex, a brain area critical for memory, contains neurons that fire when a rodent is in a certain location (eg, grid cells), or when a monkey looks at certain locations. In rodents, these spatial representations align to visual objects in the environment by firing when the animal is in a preferred location defined by relative position of visual environmental features. Recently, our laboratory found that simultaneously recorded entorhinal neurons in monkeys can exhibit different spatial reference frames for gaze position, including a reference frame of visual environmental features. We also discovered that most of the neurons represent gaze position. These results suggest that gaze information in multiple spatial reference frames is a potent signal used in the primate memory system. Here, I describe how these findings support three underappreciated views of the hippocampal memory system.