SPATIAL NAVIGATION AND THE REPRESENTATION OF PLACE AND HEAD DIRECTION INFORMATION IN THE PRIMATE HIPPOCAMPUS

Abstract

The present study sought to advance our understanding of the neural correlates of the map-and-compass system in the primate hippocampus by examining the conjunctive encoding of location and direction information in place cells. A subject monkey was trained to perform a virtual taxi driver task which involves navigating towards target locations initially obscured from view. As multiple routes are available, the monkey has to make use of its spatial map to reach the target via the shortest path. Majority of hippocampal cells exhibited significant place selectivity. However, contrary to our expectations, the number of place fields representing each location was not correlated with the frequency of traversal. Approximately one-third of place fields exhibited significant direction tuning. Although individual place fields showed independent directionalities, there was a tendency towards uniform direction preferences at some locations. Together, these findings suggest that place cells support self-localization and path-planning processes involved in goal-directed navigation.