Adult-born hippocampal neurons mature into activity-dependent responsiveness.
The mammalian hippocampus is a highly plastic brain structure in which new neurons are generated throughout adulthood. Do these new neurons qualitatively and quantitatively participate in the activity-dependent gene expression after challenging the hippocampus in a learning task? Adult mice were injected with bromodeoxyuridine (BrdU) to label dividing cells and indeed, individual BrdU-labelled new neurons expressed the immediate early gene protein (IEGp) c-fos during the acquisition phase of the Morris water maze task to the same extend as older granule cells. To assess the responsiveness of all new neurons we also analysed the expression patterns of three IEGps (c-fos, zif268 and Homer1A) after kainic acid (KA)- or pentylenetetrazol (PTZ)-induced seizures. We found that after a maturation period of between 2 and 5 weeks a comparable ratio of adult-generated granule cells participated in IEGp-expression as in the population of older granule cells. Thus, new neurons appear quantitatively integrated into hippocampal circuits, suggestive of a relevant contribution to hippocampal function.
Jessberger
Sebastian
S
VolkswagenStiftung Research Group at the Department of Experimental Neurology, Charité University Hospital, Humboldt University Berlin, Robert-Rössle-Str. 10, D-13125 Berlin, Berlin-Buch, Germany.
Kempermann
Gerd
G
D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D016922:Cellular Senescence / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D017781:Genes, Immediate-Early / Q000235:genetics / Q000502:physiology; D006624:Hippocampus / Q000166:cytology* / Q000254:growth & development; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007608:Kainic Acid; D018782:Maze Learning; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology*; D010433:Pentylenetetrazole; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism
D010751:Phosphopyruvate Hydratase; D001973:Bromodeoxyuridine; D007608:Kainic Acid; D010433:Pentylenetetrazole