The relationship between monkey hippocampus place-related neural activity and action in space.

To solve complex spatial problems like visual scanning and spatial navigation, animals must explore and actively sense an array of environmental stimuli. Recent studies have led to an agreement that the hippocampal formation (HF) is essential to the internal representation of spatial relation in animals. In the present study, neural activity was recorded from the HF of three monkeys, which steered a cab to various locations by pressing the appropriate bars (spatial moving task). Place-related activity of most HF neurons persisted even if the direction the monkey faced was rotated during the task. However, when the experimenter, rather than the monkey, controlled the device, the place-related neural activity of most HF neurons turned out to be obscure. The results suggest that the HF represents space effectively in situations in which the animal acts in space.