title: Septo-temporal gradients of neurogenesis and activity in 13-month-old rats.
abstract: Recent studies suggest that hippocampal function is partially dissociable along its septo-temporal axis: the septal hippocampus is more critical for spatial processing, while the temporal hippocampus may be more important for non-spatial-related behavior. In young adults, water maze training specifically activates new neurons in the temporal hippocampus, but it is unknown whether subregional differences are maintained in older animals, which have reduced neurogenesis levels. We therefore examined gradients of activity-related Fos expression and neurogenesis in 13-month-old rats and found that neurogenesis occurs relatively evenly throughout the dentate gyrus. Water maze experience significantly increased Fos expression in the suprapyramidal blade and Fos was highest in the septal pole of the dentate gyrus whether the animal learned a platform location, swam in the absence of a platform or remained in their cage. No Fos+ young neurons were found using typical markers of immature neurons. However, Fos expression in the subgranular zone, where adult-born neurons predominate, was disproportionally high in the temporal dentate gyrus. These findings indicate that adult-born neurons in the temporal hippocampus are preferentially activated compared with older neurons.
authors.affiliation: Unit on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA. snyderjason@mail.nih.gov
authors.forename: Jason S
authors.initials: JS
authors.lastname: Snyder
authors.forename: Preethi
authors.initials: P
authors.lastname: Ramchand
authors.forename: Sarah
authors.initials: S
authors.lastname: Rabbett
authors.forename: Ruvim
authors.initials: R
authors.lastname: Radik
authors.forename: J Martin
authors.initials: JM
authors.lastname: Wojtowicz
authors.forename: Heather A
authors.initials: HA
authors.lastname: Cameron
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D020665:Septum of Brain / Q000166:cytology / Q000502:physiology*; D012794:Sialic Acids / Q000378:metabolism; D013037:Spatial Behavior / Q000502:physiology*
chemical_list: D039842:Neural Cell Adhesion Molecule L1; D016760:Proto-Oncogene Proteins c-fos; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule; D001973:Bromodeoxyuridine