44. Maki RA, Tyurin VA, Lyon RC, Hamilton RL, DeKosky ST, et al. (2009) Aberrant expression of myeloperoxidase in astrocytes promotes phospholipid oxidation and memory deficits in a mouse model of Alzheimer disease. J Biol Chem 284: 3158–3169. 45. Everse J, Coates PW (2007) Neurodegeneration and peroxidases. Neurobiol Aging. 46. Daynes RA, Araneo BA, Ershler WB, Maloney C, Li GZ, et al. (1993) Altered regulation of IL-6 production with normal aging. Possible linkage to the age- associated decline in dehydroepiandrosterone and its sulfated derivative. J Immunol 150: 5219–5230. 47. Keller ET, Wanagat J, Ershler WB (1996) Molecular and cellular biology of interleukin-6 and its receptor. Front Biosci 1: d340–357. 48. Ali SS, Xiong C, Lucero J, Behrens MM, Dugan LL, et al. (2006) Gender differences in free radical homeostasis during aging: shorter-lived female C57BL6 mice have increased oxidative stress. Aging Cell 5: 565–574. 49. Infanger DW, Sharma RV, Davisson RL (2006) NADPH oxidases of the brain: distribution, regulation, and function. Antioxid Redox Signal 8: 1583–1596. 50. Thiels E, Klann E (2002) Hippocampal memory and plasticity in superoxide dismutase mutant mice. Physiol Behav 77: 601–605. 51. Kishida KT, Klann E (2007) Sources and targets of reactive oxygen species in synaptic plasticity and memory. Antioxid Redox Signal 9: 233–244. 52. Hunsaker MR, Rosenberg JS, Kesner RP (2008) The role of the dentate gyrus, CA3a,b, and CA3c for detecting spatial and environmental novelty. Hippo- campus 18: 1064–1073. 53. Kausler DH (1994) Learning and Memory in Normal Aging, Academic Press, San Diego, CA. 54. Kesner RP (2007) Behavioral functions of the CA3 subregion of the hippocampus. Learn Mem 14: 771–781. 55. Wilson IA, Gallagher M, Eichenbaum H, Tanila H (2006) Neurocognitive aging: prior memories hinder new hippocampal encoding. Trends Neurosci 29: 662–670. IL-6 and Cognitive Changes 56. Gilbert PE, Kesner RP (2006) The role of the dorsal CA3 hippocampal subregion in spatial working memory and pattern separation. Behav Brain Res 169: 142–149. 57. Hunsaker MR, Tran GT, Kesner RP (2008) A double dissociation of subcortical hippocampal efferents for encoding and consolidation/retrieval of spatial information. Hippocampus 18: 699–709. 58. Bakker A, Kirwan CB, Miller M, Stark CE (2008) Pattern separation in the human hippocampal CA3 and dentate gyrus. Science 319: 1640–1642. 59. Driscoll I, Hamilton DA, Yeo RA, Brooks WM, Sutherland RJ (2005) Virtual navigation in humans: the impact of age, sex, and hormones on place learning. Horm Behav 47: 326–335. 60. Moffat SD, Zonderman AB, Resnick SM (2001) Age differences in spatial memory in a virtual environment navigation task. Neurobiol Aging 22: 787–796. 61. Kinney JW, Davis CN, Tabarean I, Conti B, Bartfai T, et al. (2006) A specific role for NR2A-containing NMDA receptors in the maintenance of parvalbumin and GAD67 immunoreactivity in cultured interneurons. J Neurosci 26: 1604–1615. 62. Hall D, Han S, Dugan LL (2009) In vivo optical imaging of dihydroethidium oxidation in the mouse brain employing fluorescence intensity and lifetime contrast. 63. Benice TS, Raber J (2008) Object recognition analysis in mice using nose-point digital video tracking. J Neurosci Methods 168: 422–430. 64. Buxbaum JN, Ye Z, Reixach N, Friske L, Levy C, et al. (2008) Transthyretin protects Alzheimer’s mice from the behavioral and biochemical effects of Abeta toxicity. Proc Natl Acad Sci U S A 105: 2681–2686. 65. Prut L, Abramowski D, Krucker T, Levy CL, Roberts AJ, et al. (2007) Aged APP23 mice show a delay in switching to the use of a strategy in the Barnes maze. Behav Brain Res 179: 107–110. PLoS ONE | www.plosone.org 13 May 2009 | Volume 4 | Issue 5 | e5518