Place field repetition and spatial learning in a multicompartment environment

Abstract

Recent studies have shown that place cells in the hippocampus possess firing fields that repeat in physically similar, parallel environments. These results imply that it should be difficult for animals to distinguish parallel environments at a behavioral level. To test this, we trained rats on a novel odor‐location task in an environment with four parallel compartments which had previously been shown to yield place field repetition. A second group of animals was trained on the same task, but with the compartments arranged in different directions, an arrangement we hypothesised would yield less place field repetition. Learning of the odor‐location task in the parallel compartments was significantly impaired relative to learning in the radially arranged compartments. Fewer animals acquired the full discrimination in the parallel compartments compared to those trained in the radial compartments, and the former also required many more sessions to reach criterion compared to the latter. To confirm that the arrangement of compartments yielded differences in place cell repetition, in a separate group of animals we recorded from CA1 place cells in both environments. We found that CA1 place cells exhibited repeated fields across four parallel local compartments, but did not do so when the same compartments were arranged radially. To confirm that the differences in place field repetition across the parallel and radial compartments depended on their angular arrangement, and not incidental differences in access to an extra‐maze visual landmark, we repeated the recordings in a second set of rats in the absence of the orientation landmark. We found, once again, that place fields showed repetition in parallel compartments, and did not do so in radially arranged compartments. Thus place field repetition, or lack thereof, in these compartments was not dependent on extra‐maze cues. Together, these results imply that place field repetition constrains spatial learning. © 2015 Wiley Periodicals, Inc.

DG-CA3 circuitry mediates hippocampal representations of latent information

“…1a ). Previous results have demonstrated that point of entry can modulate hippocampal representations across different compartments 9–11 . In our paradigm, entry to the single compartment through either doorway is associated with a distinct recent history including the animal’s spatial location, direction of running within the hallway, and the turns made as the mouse enters the larger 2D compartment.…”

Qualitative differences in memory for vista and environmental spaces are caused by opaque borders, not movement or successive presentation

“…Importantly, across multiple interconnected spaces (i.e., within ES) often cells are not firing at a unique location only. Rather, the same cell may fire again (is reused) within different vista spaces (Grieves, Jenkins, Harland, Wood, & Dudchenko, 2016;Skaggs & McNaughton, 1998;Spiers, Hayman, Jovalekic, Marozzi, & Jeffery, 2015). Transferred to the present experimentation, a single place cell might fire in multiple corridors, but it will not do so at corresponding locations within a single VS room.…”

Spatially periodic activation patterns of retrosplenial cortex encode route sub-spaces and distance travelled

“…Recurrence in spatial firing patterns has also been reported in several other structures, most notably in the form of grid cells of the mEC or repeating place fields of the HPC [27][28][29][30][31][32][33][34][35][36][37][38][39][40] . However, the current findings differ from previous work in several important ways.…”