Characterization of hippocampal dentate gyrus place cells.

Abstract

The hippocampus plays an essential role in learning and memory. The discovery of place cells

in the hippocampus by O’Keefe in 1971 demonstrated that the hippocampus plays a crucial

role in spatial navigation. These place cells are found in the three major sub-regions of the

hippocampus: Dentate gyrus (DG), Cornu Ammonis 1 and 3 (CA1 &CA3). Place cells tend

to fire at a specific location in an environment. Thus, this shows that these neurons encode a

spatial representation of the environment. Hence, the hippocampus has been assumed to play

a role in the formation of a cognitive map which aids in navigation and in memory. A rat was

first pre-trained and then made to explore a circular open arena for 10 minutes, for four

sessions, with an inter-session interval of 5 minutes. Results showed that some of the recorded

neurons in the DG region have an ascribed place cell activity and these neurons fire stably, at

the same location, across all four sessions. These results thus re-established the characteristics

of the DG place cells that were previously found.