title: Place cells. Large environments reveal the statistical structure governing hippocampal representations.
abstract: The rules governing the formation of spatial maps in the hippocampus have not been determined. We investigated the large-scale structure of place field activity by recording hippocampal neurons in rats exploring a previously unencountered 48-meter-long track. Single-cell and population activities were well described by a two-parameter stochastic model. Individual neurons had their own characteristic propensity for forming fields randomly along the track, with some cells expressing many fields and many exhibiting few or none. Because of the particular distribution of propensities across cells, the number of neurons with fields scaled logarithmically with track length over a wide, ethological range. These features constrain hippocampal memory mechanisms, may allow efficient encoding of environments and experiences of vastly different extents and durations, and could reflect general principles of population coding.
authors.affiliation: Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA 20147, USA. Department of Psychology, University of Cambridge, Cambridge CB2 3EB, UK. richp@janelia.hhmi.org leea@janelia.hhmi.org.
authors.forename: P Dylan
authors.initials: PD
authors.lastname: Rich
authors.affiliation: Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA 20147, USA.
authors.forename: Hua-Peng
authors.initials: HP
authors.lastname: Liaw
authors.affiliation: Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA 20147, USA. richp@janelia.hhmi.org leea@janelia.hhmi.org.
authors.forename: Albert K
authors.initials: AK
authors.lastname: Lee
mesh_terms: D000200:Action Potentials; D000818:Animals; D001931:Brain Mapping; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000502:physiology*; D004567:Electrodes, Implanted; D005106:Exploratory Behavior; D008297:Male; D018782:Maze Learning; D008568:Memory / Q000502:physiology; D009949:Orientation; D016012:Poisson Distribution; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D013028:Space Perception