Affordable Access

deepdyve-link
Publisher Website

Alternating predictive and short-term memory modes of entorhinal grid cells.

Authors
  • De Almeida, Licurgo1
  • Idiart, Marco
  • Villavicencio, Aline
  • Lisman, John
  • 1 Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Type
Published Article
Journal
Hippocampus
Publisher
Wiley (John Wiley & Sons)
Publication Date
Aug 01, 2012
Volume
22
Issue
8
Pages
1647–1651
Identifiers
DOI: 10.1002/hipo.22030
PMID: 22549964
Source
Medline
License
Unknown

Abstract

Several lines of evidence indicate that the entorhinal cortex has memory functions, but such functions have not been previously found in grid cells, a cell type that provides major input to the hippocampus. We examined the firing of grid cells as rats crossed (runs) through grid cell vertices. We found that on some runs, firing tended to occur mostly inbound as the rat approached a vertex center while on other runs firing occurred mainly outbound. These results suggest that cells have a predictive mode (inbound firing) in which they represent a position ahead of the animal and a short term memory (STM) mode (outbound firing) in which they represent positions just passed through. Analysis of cell pairs showed that when vertex crossings were less than 1 second apart, the two cells tended to have the same mode. This indicates that modes are a network property. The tendency to have the same mode disappeared if crossings were separated by 2-3 seconds, suggesting that modes alternate on the time scale of seconds. There was a small but statistically significant behavioral correlate of modes: velocity was slightly less in the STM mode. Both modes were organized by theta and gamma oscillations. The results suggest that the dual requirement for hippocampal storage and recall is met by rapidly alternating modes appropriate for predicting the future and storing the recent past.

Report this publication

Statistics

Seen <100 times