title: Distinct speed dependence of entorhinal island and ocean cells, including respective grid cells.
abstract: Entorhinal-hippocampal circuits in the mammalian brain are crucial for an animal's spatial and episodic experience, but the neural basis for different spatial computations remain unknown. Medial entorhinal cortex layer II contains pyramidal island and stellate ocean cells. Here, we performed cell type-specific Ca(2+) imaging in freely exploring mice using cellular markers and a miniature head-mounted fluorescence microscope. We found that both oceans and islands contain grid cells in similar proportions, but island cell activity, including activity in a proportion of grid cells, is significantly more speed modulated than ocean cell activity. We speculate that this differential property reflects island cells' and ocean cells' contribution to different downstream functions: island cells may contribute more to spatial path integration, whereas ocean cells may facilitate contextual representation in downstream circuits.
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Chen
authors.initials: C
authors.lastname: Sun
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Takashi
authors.initials: T
authors.lastname: Kitamura
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Jun
authors.initials: J
authors.lastname: Yamamoto
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Jared
authors.initials: J
authors.lastname: Martin
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Michele
authors.initials: M
authors.lastname: Pignatelli
authors.affiliation: James H. Clark Center, Stanford University, Stanford, CA 94305;
authors.forename: Lacey J
authors.initials: LJ
authors.lastname: Kitch
authors.affiliation: James H. Clark Center, Stanford University, Stanford, CA 94305; Cracking the Neural Code Program, Stanford University, Stanford, CA 94305; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305;
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Schnitzer
authors.affiliation: RIKEN-Massachusetts Institute of Technology Center for Neural Circuit Genetics, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139 tonegawa@mit.edu.
authors.forename: Susumu
authors.initials: S
authors.lastname: Tonegawa
mesh_terms: D000200:Action Potentials; D000818:Animals; D001931:Brain Mapping / Q000379:methods; D002118:Calcium / Q000378:metabolism; D000229:Dependovirus; D018728:Entorhinal Cortex / Q000166:cytology*; D005456:Fluorescent Dyes; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D008959:Models, Neurological; D009434:Neural Pathways / Q000166:cytology; D009474:Neurons / Q000166:cytology
chemical_list: D005456:Fluorescent Dyes; D002118:Calcium
keywords: calcium imaging; entorhinal; grid cell; hippocampus; speed