title: Topography of Place Maps along the CA3-to-CA2 Axis of the Hippocampus.
abstract: We asked whether the structural heterogeneity of the hippocampal CA3-CA2 axis is reflected in how space is mapped onto place cells in CA3-CA2. Place fields were smaller and sharper in proximal CA3 than in distal CA3 and CA2. The proximodistal shift was accompanied by a progressive loss in the ability of place cells to distinguish configurations of the same spatial environment, as well as a reduction in the extent to which place cells formed uncorrelated representations for different environments. The transition to similar representations was nonlinear, with the sharpest drop in distal CA3. These functional changes along the CA3-CA2 axis mirror gradients in gene expression and connectivity that partly override cytoarchitectonic boundaries between the subfields of the hippocampus. The results point to the CA3-CA2 axis as a functionally graded system with powerful pattern separation at the proximal end, near the dentate gyrus, and stronger pattern completion at the CA2 end.
authors: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7489 Trondheim, Norway. Electronic address: li.lu@ntnu.no.
authors: Li
authors: L
authors: Lu
authors: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7489 Trondheim, Norway.
authors: Kei M
authors: KM
authors: Igarashi
authors: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7489 Trondheim, Norway.
authors: Menno P
authors: MP
authors: Witter
authors: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7489 Trondheim, Norway.
authors: Edvard I
authors: EI
authors: Moser
authors: Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Olav Kyrres Gate 9, MTFS, 7489 Trondheim, Norway. Electronic address: may-britt.moser@ntnu.no.
authors: May-Britt
authors: MB
authors: Moser
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001931:Brain Mapping; D056651:CA2 Region, Hippocampal / Q000166:cytology*; D056654:CA3 Region, Hippocampal / Q000166:cytology*; D004558:Electric Stimulation; D005247:Feeding Behavior; D005508:Food Deprivation; D008297:Male; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D062206:Spatial Analysis