title: Encoding and storage of spatial information in the retrosplenial cortex.
abstract: The retrosplenial cortex (RSC) is part of a network of interconnected cortical, hippocampal, and thalamic structures harboring spatially modulated neurons. The RSC contains head direction cells and connects to the parahippocampal region and anterior thalamus. Manipulations of the RSC can affect spatial and contextual tasks. A considerable amount of evidence implicates the role of the RSC in spatial navigation, but it is unclear whether this structure actually encodes or stores spatial information. We used a transgenic mouse in which the expression of green fluorescent protein was under the control of the immediate early gene c-fos promoter as well as time-lapse two-photon in vivo imaging to monitor neuronal activation triggered by spatial learning in the Morris water maze. We uncovered a repetitive pattern of cell activation in the RSC consistent with the hypothesis that during spatial learning an experience-dependent memory trace is formed in this structure. In support of this hypothesis, we also report three other observations. First, temporary RSC inactivation disrupts performance in a spatial learning task. Second, we show that overexpressing the transcription factor CREB in the RSC with a viral vector, a manipulation known to enhance memory consolidation in other circuits, results in spatial memory enhancements. Third, silencing the viral CREB-expressing neurons with the allatostatin system occludes the spatial memory enhancement. Taken together, these results indicate that the retrosplenial cortex engages in the formation and storage of memory traces for spatial information.
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095;Neurobiology Centre, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland; and silvaa@mednet.ucla.edu r.czajkowski@nencki.gov.pl.
authors.forename: Rafał
authors.initials: R
authors.lastname: Czajkowski
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095;
authors.forename: Balaji
authors.initials: B
authors.lastname: Jayaprakash
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095;
authors.forename: Brian
authors.initials: B
authors.lastname: Wiltgen
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095;
authors.forename: Thomas
authors.initials: T
authors.lastname: Rogerson
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095;
authors.forename: Mikael C
authors.initials: MC
authors.lastname: Guzman-Karlsson
authors.affiliation: Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Barth
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Trachtenberg
authors.affiliation: Departments of Neurobiology, Integrative Center for Learning and Memory, Semel Institute, Brain Research Institute,Psychiatry, andPsychology, University of California, Los Angeles, CA 90095; silvaa@mednet.ucla.edu r.czajkowski@nencki.gov.pl.
authors.forename: Alcino J
authors.initials: AJ
authors.lastname: Silva
mesh_terms: D000818:Animals; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006179:Gyrus Cinguli / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D018782:Maze Learning / Q000502:physiology; D008568:Memory / Q000502:physiology*; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal / Q000379:methods; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D013028:Space Perception / Q000502:physiology*
chemical_list: C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D016760:Proto-Oncogene Proteins c-fos; D049452:Green Fluorescent Proteins