Open access

Brain Reserve Regulators in Alzheimer’s Disease

Written By

Ivana Delalle

Submitted: April 24th, 2012 Published: May 15th, 2013

DOI: 10.5772/53658

Chapter metrics overview

1,969 Chapter Downloads

View Full Metrics

1. Introduction

Brain reserve refers to the ability of the brain to tolerate pathological changes such as those seen in AD before manifesting clinical signs and symptoms [1-3]. Neurotrophic factors (NTFs), most notably Brain Derived Neurotrophic Factor (BDNF) and its receptor Tyrosine kinase B (TrkB), regulate synaptic plasticity and functional efficiency in adulthood [4-6] and thus may influence brain reserve. BDNF/TrkB signaling affects memory formation and retention [7,8], determines neurite length [9,10], and governs regeneration upon neuronal injury [11,12] by modifying neuronal cytoskeleton. Abnormalities in the neuronal cytoskeleton are well documented in AD. However, how these abnormalities affect AD progression remains unclear. In Drosophila, neurodegeneration stems directly from mutations in alpha and beta subunits of the actin capping protein (CP), demonstrating that a mutation in a gene encoding an actin cytoskeleton regulator can lead to demise of neurons [13]. Further, a causative role for actin cytoskeleton abnormalities in neurotoxicity has been documented in a Drosophila tauopathy model [14].

Important evidence that cytoskeletal abnormalities are critically involved in the pathogenesis of neurodegeneration stems from the studies demonstrating the effect of apolipoprotein E isoform ε4 (ApoE ε4), the well-documented genetic risk factor for the most common form of AD, late-onset AD [15], on neuronal cytoskeleton. In the United States, the ApoE ε4 allele occurs in 60% of AD patients. ApoE ε4 inhibits neurite outgrowth in cultured neuronal cells [16] and correlates with the simplification of dendritic branching patterns in the brains of AD patients [17]. ApoE ε4 dose inversely correlates with dendritic spine density in dentate gyrus neurons of both AD and aged normal controls [18]. Overexpression and neuron-specific proteolytic cleavage of ApoE ε4 result in tau hyperphosphorylation in neurons of transgenic mice, suggesting a role of ApoE ε4 in cytoskeletal destabilization and the development of AD-related neuronal deficits [19,20]. Humanized ApoE ε4 knock-in homozygous transgenic mice exhibit cognitive deficits before the onset of age-dependent neuropathology including AD-associated neurofibrillary tangles and neuritic plaques [21,22].

While the relationships between BDNF gene polymorphisms and AD are not yet fully understood [23-25], there is compelling evidence that epigenetic regulation connects BDNF/TrkB signaling with learning and memory. Exercise restored TrkB in ApoE ε4 mice to the level observed in ε3 mice and increased synaptophysin (a marker of synaptic function) in ε4 mice; hippocampal BDNF levels were similarly increased in both ε3 and ε4 mice after exercise [26]. Exposure to an enriched environment for three to four weeks also caused dramatic increase in BDNF mRNA in mouse hippocampus [27]. Understanding the regulation of BDNF/TrkB signaling in AD pathogenesis, particularly in individuals carrying ApoE ε4, could be of great clinical and public health importance because BDNF is inducible and may be one of the key molecules mediating the beneficial effect of certain lifestyle measures (environmental enrichment, increased aerobic physical activity, lower caloric intake) [28-30] on the risk of developing dementia.


2. Neuronal cytoskeleton regulator actin capping protein ß2 (Capzb2) and BDNF/TrkB signaling

As hyperphosphorylated tau gives rise to neurofibrillary tangles in AD, dystrophic neurites, marked by reduced length and poor branching, become apparent. In parallel, perisomatic proliferation of dendrites and sprouting of distal dystrophic neurites take place[31]. These morphological changes in neurons during AD progression indicate major cytoskeletal reorganization raising the possibility that microtubules and microfilaments may represent a target for pathobiological mechanisms underlying AD. The presence of growth cone-like structures on distal ends of dystrophic neurites suggests that regenerative response accompanies cytoskeleton degeneration in AD [31].

Changes in growth cone morphology, motility, and direction of growth are controlled by interactions between F-actin and microtubules and their associated proteins [32]. The growth cone morphology is characterized by lamellipodia, which are the veil-like extensions at the periphery, and filopodia, which are narrow, spiky extensions coming from the periphery of the growth cone. Interestingly, APP concentrates in lamellipodia where it is proposed to play a role in growth cone motility and neurite outgrowth [33]. Upon acute neuronal injury, the first critical steps that initiate regenerative response are microtubule polymerization and F-actin cytoskeleton rearrangement leading to the formation of a motile growth cone [34]. Actin cytoskeleton regulator CP (F-actin capping protein, CapZ) is an α/β heterodimer that binds the barbed end of F-actin thus blocking the access of actin monomers to the fast growing end. Both mammalian and Drosophila CP subunits play a critical role in the organization and dynamics of lamellipodia and filopodia in non-neuronal cells [35]. One of the mammalian β-subunit isoforms, Capzb2, is predominantly expressed in the brain [36]. Capzb2 not only caps F-actin barbed end but also binds βIII-tubulin directly, affecting the rate and the extent of microtubule polymerization in the presence of tau [37]. Moreover, Capzb2 - βIII-tubulin interaction is indispensable for normal growth cone morphology and neurite length (Figure 1) [37].

Figure 1.

[37]: Capzb2-EGFP (green) expression in mouse hippocampal neurons. In addition to soma and processes, Capzb2 is expressed in growth cones (red- ß-tubulin, blue- nuclei).

Interestingly, the interaction between actin capping protein and ß-tubulin has been uncovered in a mass spectrometry screen for the alterations in protein-target binding in vivo in response to spatial learning [38], a process that requires BDNF [39].

In line with the previously documented increased cytoskeletal reorganization including dendritic proliferation and sprouting in neurons of AD patients [40,41,31], we recently demonstrated increased expression of Capzb2 (Figure 2) and TrkB in mid-stages (Braak and Braak III-IV, BBIII-IV) AD pathology[42].

Figure 2.

[42]: Hippocampal pyramidal neurons from a control case contain less Capzb2 mRNA (higher ΔCT) than the neurons from Braak and Braak III-IV AD cases (**p<0.01, Student’s t test).

BDNF binding to the TrkB receptor initiates intracellular cascades involving cell survival, growth, and differentiation via mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and phospholipase C-g (PLCγ) signaling pathways, as recently reviewed [43]. PI3K and MAPK simultaneous triggering alters both actin and microtubule dynamics needed for dendrite branching [43]. BDNF has been shown to promote growth of undifferentiated dendrites and axons in cultured hippocampal pyramidal neurons [44], a process that requires Capzb2 [37]. Thus, the expression of Capzb2 may represent one of the likely down-stream read-outs for BDNF-TrkB neuronal signaling. In a rat model of dementia there is activity-dependent, synapse-specific regulation of CapZ redistribution possibly important in both maintenance and remodeling of synaptic connections receiving spatial and temporal patterns of inputs [45].


3. Increased expression of TrkB and Capzb2 accompanies preserved cognitive status in early AD pathology

Recent study compared mRNA (Figure 3) and protein (Figure 4) expression of BDNF, TrkB and Capzb2 in samples of neuropathologically normal and cognitively intact subjects (controls), with samples of persons with AD-related pathological changes who were cognitively intact prior to death (Clinical Dementia Rating zero, CDR0), and samples of persons with AD-related pathological changes as well as early clinical dementia (CDR0.5 – 1) [46]. This approach was possible due to the existence of a unique sample of Framingham Heart Study (FHS) participants who have undergone repeated antemortem cognitive testing and brain imaging [47,48]. All FHS participants in the FHS have undergone screening cognitive tests (an MMSE) once in two years and have also had a more detailed cognitive assessment examining multiple cognitive domains once in 1974-75, once in 1999-2004 and at least twice thereafter. The presence or absence of dementia in all FHS participants is defined using DSM-IV criteria that require impairment in memory and in at least one other area of cognitive function, as well as documented functional disability. AD is defined using NINCDS-ADRDA criteria for definite, probable or possible AD[49]. All FHS participants are invited to become brain donors and the nearly 700 persons who have accepted this invitation undergo a detailed neuropsychological testing [50,51], at least once every 2 years beyond age 75 years. Persons who screen positive or are otherwise referred (by self, family or treating physicians) undergo detailed neurological and neuropsychological assessment, informant interview (with a physician administered CDR) and a review of hospital records, nursing home notes, brain imaging and laboratory tests. A structured family interview (including Blessed Dementia and Hachinski scales) [52,53] is conducted with the next-of-kin based on which a retrospective CDR score is assigned after the participant dies. The retrospective CDR is very similar to the retrospective collateral dementia interview validated by Davis and colleagues (1991)[54]. A final clinical decision regarding the presence or absence of dementia, diagnosis of dementia type and date of onset/diagnosis is made by a clinical consensus panel including behavioral neurologists and neuropsychologists who review all available records including records at the time of death. All deaths are reviewed to assign a cause of death and to determine if dementia was present or absent at the time of death. The neuropathological report is generated prior to a final clinico-pathological conference during which the clinical diagnoses and pathological findings are discussed.

Hippocampi from selected FHS cases were used to determine whether specifically vulnerable population of CA1 neurons shows a compensatory response to the neuropathological changes of Alzheimer Disease (AD) and whether that response depends on an up-regulation of the BDNF pathway. The expression of TrkB and Capzb2 in CA1 hippocampal neurons of individuals with preserved cognitive status (CDR 0) and initial neurofibrillary tangle formation was increased in comparison to cognitively intact individuals without any neurofibrillary tangles (Figure 3) [46]. In contrast, BDNF expression remained unchanged, raising the possibility that the up-regulated TrkB expression in CDR0 individuals is responsible for the increase in BDNF/TrkB signaling tapping the brain reserve (Figure 3) [46]. In the group of individuals with more advanced tangle formation and early to mild dementia (CDR 0.5-1), the increase in TrkB expression and the unchanged expression of BDNF might have been insufficient to provide adequate brain reserve (Figure 3) [46].

Figure 3.

[46]: TrkB, BDNF, and Capzb2 mRNAs expression in control, CDR 0 (no dementia) and CDR 0.5-1 (mild dementia) subjects. TrkB mRNA expression is significantly increased (lower ΔCT) in subjects with early AD pathology (BBI-II) but no dementia (A). BDNF mRNA expression is similar in all groups examined (B). Capzb2 mRNA is significantly increased (lower ΔCT) in cases with AD pathology (C). Fold-increases of mean mRNA expression of TrkB and Capzb2 in cases with AD pathology in comparison to controls (D).

Figure 4.

[46]: Immunohistochemistry for TrkB (A-C), BDNF (D-F), and Capzb2 (G-I) in representative individuals from control, CDR0, and CDR1 groups reflects established trends in mRNA expression. Immunohistochemistry for tau highlights intensity of neurofibrillary changes in a CDR0 subject (K) and in a CDR1 subject (L), while the control is free of neuropathology (J).

In light of the reported restoration of learning and memory functions in AD animal models upon BDNF gene delivery [55], exogenous intervention to boost BDNF/TrkB signaling might appear a compelling therapy in early AD. However, the experiments by Frank et al. (1996) suggest that the exposure of developing and adult rodent hippocampal neurons to BDNF in vitro and in vivo results in long-term functional desensitization to BDNF and down regulation of TrkB mRNA [56]. It is possible that BDNF/TrkB signaling is differentially regulated in healthy vs. diseased hippocampal neurons. Nevertheless, the reported increase in TrkB mRNA expression in astrocytes occasionally associated with senile plaques in hippocampi of AD brains raises concerns that the administration of neurotrophic factors could promote gliosis and plaque formation [57]. Importantly, if the observed increase in TrkB expression in cognitively intact FHS subjects with initial formation of neurofibrillary tangles constitutes brain reserve, down regulation of TrkB might represent a potentially harmful side-effect of exogenous BDNF delivery.


4. Conclusion

One in five persons currently 65 years old will develop clinical Alzheimer’s dementia in their lifetime. However, postponing the onset of clinical disease by as little as five years could halve individual risk and population burden of disease [58,59]. Since the timing of clinical dementia onset is determined not only by the pace of pathological changes but also by brain reserve, that postponement might be possible. The study of CA1 hippocampal neurons in FHS participant brain donors[46] adds to the emerging evidence that the BDNF/TrkB pathway may be involved in the compensatory response to early AD pathology, i.e. it may underlie the biology of cognitive reserve. Consequently, an epigenetic enhancement of BDNF/TrkB signaling in persons with early cognitive changes associated with AD pathology (mild cognitive impairment, MCI, due to AD pathology)[60] and in persons with no clinical symptoms but with biomarker evidence of AD pathology (so-called preMCI due to AD pathology)[61] may be beneficial in delaying the onset of clinical dementia. The lifestyle modifications that are thought to reduce the risk of developing clinical AD, such as intake of docosahexaenoic acid (DHA) and increased exercise, appear to interact with BDNF-related synaptic plasticity[62]. As reviewed by Sananbenesi and Fischer (2009)[63], deregulation of “plasticity genes”, in particular synaptic plasticity genes, accompanies aging, a major risk for AD. Histone deacetylase inhibitors (HDACs) and environmental enrichment have been shown to reinstate learning behavior and improve memory in a CK-p25 mouse model of neurodegeneration[64], whereas altered histone acetylation is associated with age-dependent memory impairment in mice[65]. These findings make deciphering of epigenetic signatures in preserved vs. failing human cognitive functions urgent and necessary for the development of rational interventions in the progression of AD [66,67]. The prevention of clinical AD will likely require a multi-dimensional approach and the modulation of the BDNF/TrkB pathway, calibrated to each individual’s needs, might be one facet of this multi-dimensional approach.



During the progression of Alzheimer’s disease (AD), hippocampal neurons show degenerative as well as regenerative changes, possibly influenced by genes that may modify brain reserve, the ability of the brain to tolerate pathological changes in AD before manifesting clinical signs and symptoms. Recent data suggest that the expression of these genes in the hippocampal neurons correlates with the cognitive function. Identifying molecules that may promote regenerative potential and/or increase brain reserve provides novel targets for interventions in late-onset AD.


  1. 1. Valenzuela M. J Sachdev P 2006Brain reserve and cognitive decline: a non-parametric systematic review. Psychol Med 36 1065 1073
  2. 2. Riley K. P Snowdon D. A Desrosiers M. F Markesbery W. R 2005Early life linguistic ability, late life cognitive function, and neuropathology: findings from the Nun Study. Neurobiol Aging 26 341 347
  3. 3. Snowdon D. A Kemper S. J Mortimer J. A Greiner L. H Wekstein D. R et al 1996Linguistic ability in early life and cognitive function and Alzheimer’s disease in late life. Findings from the Nun Study. JAMA 275 528 532
  4. 4. Waterhouse E. G Xu B 2009New insights into the role of brain-derived neurotrophic factor in synaptic plasticity. Mol Cell Neurosci 42 81 89
  5. 5. Minichiello L 2009TrkB signalling pathways in LTP and learning. Nat Rev Neurosci 10 850 860
  6. 6. Cowansage K. K Ledoux J. E Monfils M. H 2009Brain-Derived Neurotrophic Factor: A Dynamic Gatekeeper of Neural Plasticity. Curr Mol Pharmacol.
  7. 7. Rex C. S Lin C. Y Kramar E. A Chen L. Y Gall C. M et al 2007Brain-derived neurotrophic factor promotes long-term potentiation-related cytoskeletal changes in adult hippocampus. J Neurosci 27 3017 3029
  8. 8. Lu Y Christian K Lu B 2008BDNF: a key regulator for protein synthesis-dependent LTP and long-term memory? Neurobiol Learn Mem 89 312 323
  9. 9. Miyamoto Y Yamauchi J Tanoue A Wu C Mobley W. C 2006TrkB binds and tyrosine-phosphorylates Tiam1, leading to activation of Rac1 and induction of changes in cellular morphology. Proc Natl Acad Sci U S A 103 10444 10449
  10. 10. Luo L 2000Rho GTPases in neuronal morphogenesis. Nat Rev Neurosci 1 173 180
  11. 11. Goutan E Marti E Ferrer I 1998BDNF, and full length and truncated TrkB expression in the hippocampus of the rat following kainic acid excitotoxic damage. Evidence of complex time-dependent and cell-specific responses. Brain Res Mol Brain Res 59 154 164
  12. 12. Avwenagha O Campbell G Bird M. M 2003Distribution of GAP-43, beta-III tubulin and F-actin in developing and regenerating axons and their growth cones in vitro, following neurotrophin treatment. J Neurocytol 32 1077 1089
  13. 13. Delalle I Pfleger C. M Buff E Lueras P Hariharan I. K 2005Mutations in the Drosophila orthologs of the F-actin capping protein alpha- and beta-subunits cause actin accumulation and subsequent retinal degeneration. Genetics 171 1757 1765
  14. 14. Fulga T. A Elson-schwab I Khurana V Steinhilb M. L Spires T. L et al 2007Abnormal bundling and accumulation of F-actin mediates tau-induced neuronal degeneration in vivo. Nat Cell Biol 9 139 148
  15. 15. Li Y Grupe A 2007Genetics of late-onset Alzheimer’s disease: progress and prospect. Pharmacogenomics 8 1747 1755
  16. 16. Nathan B. P Chang K. C Bellosta S Brisch E Ge N et al 1995The inhibitory effect of apolipoprotein E4 on neurite outgrowth is associated with microtubule depolymerization. J Biol Chem 270 19791 19799
  17. 17. Arendt T Schindler C Bruckner M. K Eschrich K Bigl V et al 1997Plastic neuronal remodeling is impaired in patients with Alzheimer’s disease carrying apolipoprotein epsilon 4 allele. J Neurosci 17 516 529
  18. 18. Ji Y Gong Y Gan W Beach T Holtzman D. M et al 2003Apolipoprotein E isoform-specific regulation of dendritic spine morphology in apolipoprotein E transgenic mice and Alzheimer’s disease patients. Neuroscience 122 305 315
  19. 19. Tesseur I Van Dorpe J Spittaels K Van den Haute C, Moechars D, et al. (2000Expression of human apolipoprotein E4 in neurons causes hyperphosphorylation of protein tau in the brains of transgenic mice. Am J Pathol 156 951 964
  20. 20. Brecht W. J Harris F. M Chang S Tesseur I Yu G. Q et al 2004Neuron-specific apolipoprotein e4 proteolysis is associated with increased tau phosphorylation in brains of transgenic mice. J Neurosci 24 2527 2534
  21. 21. Wang C Wilson W. A Moore S. D Mace B. E Maeda N et al 2005Human apoE4-targeted replacement mice display synaptic deficits in the absence of neuropathology. Neurobiol Dis 18 390 398
  22. 22. Klein R. C Mace B. E Moore S. D Sullivan PM Progressive loss of synaptic integrity in human apolipoprotein E4 targeted replacement mice and attenuation by apolipoprotein E2. Neuroscience 171 1265 1272
  23. 23. Riemenschneider M Schwarz S Wagenpfeil S Diehl J Muller U et al 2002A polymorphism of the brain-derived neurotrophic factor (BDNF) is associated with Alzheimer’s disease in patients lacking the Apolipoprotein E epsilon4 allele. Mol Psychiatry 7 782 785
  24. 24. Lee J Fukumoto H Orne J Klucken J Raju S et al 2005Decreased levels of BDNF protein in Alzheimer temporal cortex are independent of BDNF polymorphisms. Exp Neurol 194 91 96
  25. 25. Forlenza O. V Diniz B. S Teixeira A. L Ojopi E. B Talib L. L et al Effect of brain-derived neurotrophic factor Val66Met polymorphism and serum levels on the progression of mild cognitive impairment. World J Biol Psychiatry 11 774 780
  26. 26. Nichol K Deeny S. P Seif J Camaclang K Cotman C. W 2009Exercise improves cognition and hippocampal plasticity in APOE epsilon4 mice. Alzheimers Dement 5 287 294
  27. 27. Kuzumaki N Ikegami D Tamura R Hareyama N Imai S et al Hippocampal epigenetic modification at the brain-derived neurotrophic factor gene induced by an enriched environment. Hippocampus 21 127 132
  28. 28. Verghese J Lipton R. B Katz M. J Hall C. B Derby C. A et al 2003Leisure activities and the risk of dementia in the elderly. N Engl J Med 348 2508 2516
  29. 29. Larson E. B Wang L Bowen J. D Mccormick W. C Teri L et al 2006Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older. Ann Intern Med 144 73 81
  30. 30. Pasinetti G. M Zhao Z Qin W Ho L Shrishailam Y et al 2007Caloric intake and Alzheimer’s disease. Experimental approaches and therapeutic implications. Interdiscip Top Gerontol 35 159 175
  31. 31. Mckee A. C Kowall N. W Kosik K. S 1989Microtubular reorganization and dendritic growth response in Alzheimer’s disease. Ann Neurol 26 652 659
  32. 32. Dent E. W Gertler F. B 2003Cytoskeletal dynamics and transport in growth cone motility and axon guidance. Neuron 40 209 227
  33. 33. Sabo S. L Ikin A. F Buxbaum J. D Greengard P 2003The amyloid precursor protein and its regulatory protein, FE65, in growth cones and synapses in vitro and in vivo. J Neurosci 23 5407 5415
  34. 34. Spira M. E Oren R Dormann A Gitler D 2003Critical calpain-dependent ultrastructural alterations underlie the transformation of an axonal segment into a growth cone after axotomy of cultured Aplysia neurons. J Comp Neurol 457 293 312
  35. 35. Mejillano M. R Kojima S Applewhite D. A Gertler F. B Svitkina T. M et al 2004Lamellipodial versus filopodial mode of the actin nanomachinery: pivotal role of the filament barbed end. Cell 118 363 373
  36. 36. Schafer D. A Korshunova Y. O Schroer T. A Cooper J. A 1994Differential localization and sequence analysis of capping protein beta-subunit isoforms of vertebrates. J Cell Biol 127 453 465
  37. 37. Davis D. A Wilson M. H Giraud J Xie Z Tseng H. C et al 2009Capzb2 interacts with beta-tubulin to regulate growth cone morphology and neurite outgrowth. PLoS Biol 7: e1000208.
  38. 38. Nelson T. J Backlund P. S Jr., Alkon DL (2004Hippocampal protein-protein interactions in spatial memory. Hippocampus 14 46 57
  39. 39. Linnarsson S Bjorklund A Ernfors P 1997Learning deficit in BDNF mutant mice. Eur J Neurosci 9 2581 2587
  40. 40. Scheibel A. B Tomiyasu U 1978Dendritic sprouting in Alzheimer’s presenile dementia. Exp Neurol 60 1 8
  41. 41. Scheibel A. B 1979Dendritic changes in senile and presenile dementias. Res Publ Assoc Res Nerv Ment Dis 57 107 124
  42. 42. Kao P. F Davis D. A Banigan M. G Vanderburg C. R Seshadri S et al Modulators of cytoskeletal reorganization in CA1 hippocampal neurons show increased expression in patients at mid-stage Alzheimer’s disease. PLoS One 5: e13337.
  43. 43. Grande I Fries G. R Kunz M Kapczinski F 2010The role of BDNF as a mediator of neuroplasticity in bipolar disorder. Psychiatry Investig 7 243 250
  44. 44. Labelle C Leclerc N 2000Exogenous BDNF, NT-3 and NT-4 differentially regulate neurite outgrowth in cultured hippocampal neurons. Brain Res Dev Brain Res 123 1 11
  45. 45. Kitanishi T Sakai J Kojima S Saitoh Y Inokuchi K et al Activity-dependent localization in spines of the F-actin capping protein CapZ screened in a rat model of dementia. Genes Cells.
  46. 46. Kao P. F Banigan M. G Vanderburg C. R Mckee A. C Polgar P. R et al 2012Increased Expression of TrkB and Capzb2 Accompanies Preserved Cognitive Status in Early Alzheimer Disease Pathology. J Neuropathol Exp Neurol 71 654 664
  47. 47. Farmer M. E White L. R Kittner S. J Kaplan E Moes E et al 1987Neuropsychological test performance in Framingham: a descriptive study. Psychol Rep 60 1023 1040
  48. 48. Au R Seshadri S Wolf P. A Elias M Elias P et al 2004New norms for a new generation: cognitive performance in the framingham offspring cohort. Exp Aging Res 30 333 358
  49. 49. Mckhann G Drachman D Folstein M Katzman R Price D et al 1984Clinical diagnosis of Alzheimer’s disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer’s Disease. Neurology 34 939 944
  50. 50. Morris J. C Weintraub S Chui H. C Cummings J Decarli C et al 2006The Uniform Data Set (UDS): clinical and cognitive variables and descriptive data from Alzheimer Disease Centers. Alzheimer Dis Assoc Disord 20 210 216
  51. 51. Weintraub S Salmon D Mercaldo N Ferris S Graff-radford N. R et al 2009The Alzheimer’s Disease Centers’ Uniform Data Set (UDS): the neuropsychologic test battery. Alzheimer Dis Assoc Disord 23 91 101
  52. 52. Blessed G Tomlinson B. E Roth M 1968The association between quantitative measures of dementia and of senile change in the cerebral grey matter of elderly subjects. Br J Psychiatry 114 797 811
  53. 53. Hachinski V. C Iliff L. D Zilhka E Du Boulay GH, McAllister VL, et al. (1975Cerebral blood flow in dementia. Arch Neurol 32 632 637
  54. 54. Davis P. B White H Price J. L Mckeel D Robins L. N 1991Retrospective postmortem dementia assessment. Validation of a new clinical interview to assist neuropathologic study. Arch Neurol 48 613 617
  55. 55. Nagahara A. H Merrill D. A Coppola G Tsukada S Schroeder B. E et al 2009Neuroprotective effects of brain-derived neurotrophic factor in rodent and primate models of Alzheimer’s disease. Nat Med 15 331 337
  56. 56. Frank L Ventimiglia R Anderson K Lindsay R. M Rudge J. S 1996BDNF down-regulates neurotrophin responsiveness, TrkB protein and TrkB mRNA levels in cultured rat hippocampal neurons. Eur J Neurosci 8 1220 1230
  57. 57. Connor B Young D Lawlor P Gai W Waldvogel H et al 1996Trk receptor alterations in Alzheimer’s disease. Brain Res Mol Brain Res 42 1 17
  58. 58. Seshadri S Wolf P. A Beiser A Au R Mcnulty K et al 1997Lifetime risk of dementia and Alzheimer’s disease. The impact of mortality on risk estimates in the Framingham Study. Neurology 49 1498 1504
  59. 59. Seshadri S Wolf P. A 2007Lifetime risk of stroke and dementia: current concepts, and estimates from the Framingham Study. Lancet Neurol 6 1106 1114
  60. 60. Albert M. S Dekosky S. T Dickson D Dubois B Feldman H. H et al 2011The diagnosis of mild cognitive impairment due to Alzheimer’s disease: recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimers Dement 7 270 279
  61. 61. Sperling R. A Aisen P. S Beckett L. A Bennett D. A Craft S et al 2011Toward defining the preclinical stages of Alzheimer’s disease: recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimers Dement 7 280 292
  62. 62. Wu A Ying Z Gomez-pinilla F 2008Docosahexaenoic acid dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition. Neuroscience 155 751 759
  63. 63. Sananbenesi F Fischer A 2009The epigenetic bottleneck of neurodegenerative and psychiatric diseases. Biol Chem 390 1145 1153
  64. 64. Fischer A Sananbenesi F Wang X Dobbin M Tsai L. H 2007Recovery of learning and memory is associated with chromatin remodelling. Nature 447 178 182
  65. 65. Been E Barash A Pessah H Peleg S 2010A new look at the geometry of the lumbar spine. Spine (Phila Pa 1976) 35: E1014 1017
  66. 66. Fischer A Sananbenesi F Mungenast A Tsai L. H 2010Targeting the correct HDAC(s) to treat cognitive disorders. Trends Pharmacol Sci 31 605 617
  67. 67. Stilling R. M Fischer A 2011The role of histone acetylation in age-associated memory impairment and Alzheimer’s disease. Neurobiol Learn Mem 96 19 26

Written By

Ivana Delalle

Submitted: April 24th, 2012 Published: May 15th, 2013