Head direction cells in the primate pre-subiculum

The function of the primate hippocampus and related structures was analysed by making recordings from the hippocampus, subiculum, presubiculum, and pa rahippocampal gyrus in monkeys actively walking in the laboratory. Head dir ection cells were found in the presubiculum. The firing rate of these cells was a function of the head direction of the monkey, with a response that w as typically 10-100 times larger to the best as compared to the opposite di rection. The mean half-amplitude width of the tuning of the cells was 76 de grees. The response of head direction cells in the presubiculum was not inf luenced by the place where the monkey was, there being the same tuning to h ead direction at different places in a room, and even outside the room. The response of these cells was also independent of the "spatial view" observe d by the monkey, and also the position of the eyes in the head. The average information about head direction was 0.64 bits, about place was 0.10 bits, about spatial view was 0.27 bits, and about eye position was 0.04 bits. Th e cells maintained their tuning for periods of at least several minutes whe n the view details were obscured or the room was darkened. This representat ion of head direction could be useful together with the hippocampal spatial view cells and whole body motion cells found in primates in such spatial a nd memory functions as path integration. (C) 1999 Wiley-Liss, Inc.