title: Experience-dependent persistent expression of zif268 during rest is preserved in the aged dentate gyrus.
abstract: BACKGROUND
  Aging is typically accompanied by memory decline and changes in hippocampal function. Among these changes is a decline in the activity of the dentate gyrus (DG) during behavior. Lasting memory, however, is thought to also require recapitulation of recent memory traces during subsequent rest - a phenomenon, termed memory trace reactivation, which is compromised in hippocampal CA1 with progressive age. This process has yet to be assessed in the aged DG, despite its prominent role in age-related memory impairment. Using zif268 transcription to measure granule cell recruitment, DG activity in adult and aged animals was assessed both during spatial exploration and as animals remained at rest in the home cage in order to detect potential memory-related replay.
  
  
  RESULTS
  Consistent with the observation of memory trace reactivation in DG, the probability that an individual granule cell transcribes zif268 during rest in the animal's home cage is increased by recent experience in a novel environment. Surprisingly, a comparable increase was observed in the probability of granule cells in the aged DG expressing zif268 during rest. Moreover, no significant age-related difference was observed in the number of granule cells expressing zif268 during rest. Thus, the number and pattern of granule cell expression of zif268 during rest is preserved in aged animals, despite a significant decline in exploration-related zif268 expression.
  
  
  CONCLUSIONS
  These data lead to the hypothesis that the input the aged DG receives from backprojections from CA3 (the region widely hypothesized to mediate reactivation) remains functionally intact despite loss of innervation from the perforant path.
authors.affiliation: Department of Psychology, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5, Canada. dmarrone@wlu.ca.
authors.forename: Ali
authors.initials: A
authors.lastname: Gheidi
authors.forename: Erin
authors.initials: E
authors.lastname: Azzopardi
authors.forename: Allison A
authors.initials: AA
authors.lastname: Adams
authors.forename: Diano F
authors.initials: DF
authors.lastname: Marrone
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D056654:CA3 Region, Hippocampal / Q000378:metabolism; D018891:Dentate Gyrus / Q000378:metabolism*; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D008297:Male; D008568:Memory / Q000502:physiology*; D018613:Microscopy, Confocal; D009434:Neural Pathways / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D012146:Rest / Q000502:physiology
chemical_list: D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat
references.citation: Trends Neurosci. 2010 May;33(5):220-9
references.pmid: 20207025
references.citation: Hippocampus. 1992 Apr;2(2):189-99
references.pmid: 1308182
references.citation: Neurobiol Aging. 2011 Dec;32(12):2317.e23-32
references.pmid: 20447731
references.citation: Neurobiol Aging. 2011 Jun;32(6):1149-56
references.pmid: 19632743
references.citation: Behav Neurosci. 2001 Dec;115(6):1180-92
references.pmid: 11770050
references.citation: Nat Neurosci. 2008 Feb;11(2):209-15
references.pmid: 18193040
references.citation: Neurobiol Aging. 1984 Spring;5(1):43-8
references.pmid: 6738785
references.citation: J Sleep Res. 1998;7 Suppl 1:6-16
references.pmid: 9682188
references.citation: Neuron. 2001 Jan;29(1):145-56
references.pmid: 11182087
references.citation: Proc Natl Acad Sci U S A. 2009 Jul 14;106(28):11771-5
references.pmid: 19556537
references.citation: Prog Brain Res. 2007;163:627-37
references.pmid: 17765742
references.citation: J Neurosci. 2011 May 11;31(19):7163-7
references.pmid: 21562279
references.citation: Science. 2007 Feb 16;315(5814):961-6
references.pmid: 17303747
references.citation: J Neurosci. 2008 Jan 30;28(5):1030-3
references.pmid: 18234881
references.citation: Nat Neurosci. 2005 Nov;8(11):1560-7
references.pmid: 16222227
references.citation: Hippocampus. 2005;15(5):579-86
references.pmid: 15920719
references.citation: Neurobiol Aging. 1996 May-Jun;17(3):439-51
references.pmid: 8725906
references.citation: J Neurosci. 2009 May 27;29(21):6840-50
references.pmid: 19474311
references.citation: Nat Rev Neurosci. 2006 Jan;7(1):30-40
references.pmid: 16371948
references.citation: Proc Natl Acad Sci U S A. 1986 May;83(9):3027-31
references.pmid: 3458260
references.citation: Nat Neurosci. 2001 Mar;4(3):289-96
references.pmid: 11224546
references.citation: Hippocampus. 2010 Oct;20(10):1109-23
references.pmid: 20872737
references.citation: Neural Netw. 2005 Nov;18(9):1280-91
references.pmid: 16257176
references.citation: Nat Neurosci. 1999 Dec;2(12):1120-4
references.pmid: 10570490
references.citation: Brain Res. 1986 Nov 29;398(2):242-52
references.pmid: 3026567
references.citation: J Neurosci Res. 2012 Sep;90(9):1820-9
references.pmid: 22535445
references.citation: Hippocampus. 1992 Oct;2(4):437-44
references.pmid: 1308200
references.citation: Hippocampus. 2009 Apr;19(4):360-70
references.pmid: 19004012
references.citation: J Neurosci Methods. 1980 Dec;3(2):129-49
references.pmid: 6110810
references.citation: J Neurosci. 2008 Jul 30;28(31):7883-90
references.pmid: 18667620
references.citation: Hippocampus. 1993 Apr;3(2):165-82
references.pmid: 8353604
references.citation: J Comp Neurol. 1994 Jan 8;339(2):181-208
references.pmid: 8300905
references.citation: Behav Neurosci. 1993 Aug;107(4):618-26
references.pmid: 8397866
references.citation: Neurobiol Aging. 2011 Dec;32(12):2198-210
references.pmid: 20189687
references.citation: Nature. 2011 Jan 20;469(7330):397-401
references.pmid: 21179088
references.citation: Neuron. 2009 Jun 25;62(6):781-7
references.pmid: 19555647
references.citation: Trends Neurosci. 2006 Dec;29(12):662-70
references.pmid: 17046075
references.citation: Science. 2008 Feb 29;319(5867):1260-4
references.pmid: 18218862
references.citation: J Neurosci. 2006 Jun 14;26(24):6610-7
references.pmid: 16775149
references.citation: Neuron. 2006 Jan 5;49(1):143-55
references.pmid: 16387646
references.citation: Neuroscience. 1989;31(3):551-70
references.pmid: 2687720
references.citation: Proc Natl Acad Sci U S A. 2004 May 4;101(18):7181-6
references.pmid: 15118105
references.citation: J Neurosci. 2000 Sep 1;20(17):6587-93
references.pmid: 10964964
references.citation: J Neurosci. 2005 Feb 16;25(7):1761-8
references.pmid: 15716412
references.citation: Prog Brain Res. 1994;102:335-41
references.pmid: 7800823