title: Origin, migration and fate of newly generated neurons in the adult rodent piriform cortex.
abstract: Newly generated neurons are continuously added to the olfactory epithelium and olfactory bulbs of adult mammals. Studies also report newly generated neurons in the piriform cortex, the primary cortical projection site of the olfactory bulbs. The current study used BrdU-injection paradigms, and in vivo and in vitro DiI tracing methods to address three fundamental issues of these cells: their origin, migratory route and fate. The results show that 1 day after a BrdU-injection, BrdU/DCX double-labeled cells appear deep to the ventricular subependyma, within the white matter. Such cells appear further ventral and caudal in the ensuing days, first appearing in the rostral piriform cortex of mice at 2 days after the BrdU-injection, and at 4 days in the rat. In the caudal piriform cortex, BrdU/DCX labeled cells first appear at 4 days after the injection in mice and 7 days in rats. The time it takes for these cells to appear in the piriform cortex and the temporal distribution pattern suggest that they migrate from outside this region. DiI tracing methods confirmed a migratory route to the piriform cortex from the ventricular subependyma. The presence of BrdU/NeuN labeled cells as early as 7 days after a BrdU injection in mice and 10 days in the rat and lasting as long as 41 days indicates that some of these cells have extended survival durations in the adult piriform cortex.
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California at Irvine, Irvine, CA 92697-1275, USA.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Shapiro
authors.forename: Kwan L
authors.initials: KL
authors.lastname: Ng
authors.forename: Richard
authors.initials: R
authors.lastname: Kinyamu
authors.forename: Patricia
authors.initials: P
authors.lastname: Whitaker-Azmitia
authors.forename: Eldon E
authors.initials: EE
authors.lastname: Geisert
authors.forename: Mathew
authors.initials: M
authors.lastname: Blurton-Jones
authors.forename: Qun-Yong
authors.initials: QY
authors.lastname: Zhou
authors.forename: Charles E
authors.initials: CE
authors.lastname: Ribak
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine; D002232:Carbocyanines; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement; D048430:Cell Shape; D002470:Cell Survival; D004268:DNA-Binding Proteins; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D005456:Fluorescent Dyes; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D051379:Mice; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D008869:Microtubule-Associated Proteins / Q000032:analysis; D009419:Nerve Tissue Proteins / Q000032:analysis; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D009479:Neuropeptides / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D009830:Olfactory Bulb / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D009833:Olfactory Pathways / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling / Q000379:methods; D013997:Time Factors
chemical_list: D002232:Carbocyanines; D004268:DNA-Binding Proteins; C000714847:Dcx protein, mouse; C000714848:Dcx protein, rat; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D005456:Fluorescent Dyes; D019394:Ki-67 Antigen; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; C492380:NeuN protein, mouse; D009479:Neuropeptides; D009687:Nuclear Proteins; C024286:3,3'-dioctadecylindocarbocyanine; D001973:Bromodeoxyuridine