title: Representation of geometric borders in the developing rat.
abstract: Local space is represented by a number of functionally specific cell types, including place cells in the hippocampus and grid cells, head direction cells, and border cells in the medial entorhinal cortex (MEC). These cells form a functional map of external space already at the time when rat pups leave the nest for the first time in their life, at the age of 2.5 weeks. However, while place cells have adult-like firing fields from the outset, grid cells have irregular and variable fields until the fourth week, raising doubts about their contribution to place cell firing at young age. Recording in MEC of juvenile rats, we show that, unlike grid cells, border cells express adult-like firing fields from the first days of exposure to an open environment, at postnatal days 16-18. Thus, spatial signals from border cells may be sufficient to maintain spatially localized firing in juvenile hippocampal place cells.
authors.affiliation: Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway.
authors.forename: Tale L
authors.initials: TL
authors.lastname: Bjerknes
authors.affiliation: Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway.
authors.forename: Edvard I
authors.initials: EI
authors.lastname: Moser
authors.affiliation: Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway. Electronic address: maybm@ntnu.no.
authors.forename: May-Britt
authors.initials: MB
authors.lastname: Moser
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001931:Brain Mapping; D004567:Electrodes, Implanted; D018728:Entorhinal Cortex / Q000166:cytology* / Q000254:growth & development; D005260:Female; D006624:Hippocampus / Q000166:cytology* / Q000254:growth & development; D008297:Male; D008959:Models, Neurological; D009474:Neurons / Q000145:classification / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D013037:Spatial Behavior / Q000502:physiology*