Dissertations / Theses on the topic 'Brain – Aging'
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1
Tam, Man-kin Helena, and 譚敏堅. "Cognitive functioning of the aging brain." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/209669.
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This thesis contains two studies which examined the cognitive functioning of the aging brain. Specifically, age-related changes in processing speed and its remediation via cognitive training were studied. In study 1, younger adults (n = 34) and older adults (n = 39) were recruited to investigate the age-related differences in the relationships between processing speed and general cognitive status (GCS). Their performance in GCS (as measured by The Montreal Cognitive Assessment, Hong Kong Version), cognitive processing speed (as measured by Processing Speed Index, Wechsler Adult Intelligence Scale), cognitive inhibition (as measured by Stroop Color-Word Test), and divided attention (as measured by Color Trails Test) was examined. Current findings indicated that processing speed predicted GCS in older but not younger adults. In older adults, processing speed as a predictor accounted for an additional 13% of variance in GCS. This study further verified the relationship between processing speed and prefrontal abilities, including verbal fluency, cognitive inhibition and divided attention in aging. Findings revealed that despite the abovementioned prefrontal abilities were significantly correlated with processing speed, verbal fluency had remained the strongest predictor, accounting for 21% of variance in processing speed in older adults. Based on findings in study 1, it was anticipated that training cognitive skills including processing speed and prefrontal abilities in older adults would improve cognitive functioning in general. Therefore, in study 2, elderly people at risk of progressive cognitive decline (n = 70) were recruited to investigate the training effect of computerized cognitive training programs that aimed to improve cognitive processing speed, cognitive inhibition and divided attention. Findings indicated that cognitive processing speed and divided attention improved post-training. Results obtained from the two studies implied potential intervention through training cognitive processing speed in elderly people at risk of progressive cognitive decline. Future studies should focus on training specific effect and examining the optimal effect by modification of the training paradigms, particularly the design of the contents and level of difficulty.published_or_final_version
Clinical Psychology
Doctoral
Doctor of Psychology
2
Elobeid, Adila. "Altered proteins in the aging brain." Doctoral thesis, Uppsala universitet, Institutionen för immunologi, genetik och patologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277214.
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The classification of neurodegenerative disorders is based on the major component of the protein aggregates in the brain. The most common altered proteins associated with neurodegeneration are Hyperphosphorylated tau (HPt), beta amyloid (Aβ), alpha-synclein (αS) and transactive response DNA binding protein 43 (TDP43). In this study we assessed the incidence and the neuroanatomical distribution of proteins associated with neurodegeneration in the brain tissue of cognitively unimpaired subjects. We demonstrated the early involvement of the Locus Coeruleus (LC) with HPt pathology in cognitively unimpaired mid aged subjects, a finding which supports the notion that LC is an initiation site of HPt pathology. This may suggest that development of clinical assessment techniques and radiological investigations reflecting early LC alterations may help in identifying subjects with early stages of neurodegeneration. Furthermore, we studied a large cohort of cognitively unimpaired subjects with age at death ≥50 years and we applied the National Institute on Aging –Alzheimer’s disease (AD) Association (NIA-AA) guidelines for the assessment of AD related neuropathological changes. Interestingly, a considerable percentage of the subjects were classified as having an intermediate level of AD pathology. We also showed that the altered proteins; HPt , Aβ, αS, and TDP43 are frequently seen in the brain of cognitively unimpaired subjects with age at death ≥50 years, the incidence of these proteins increased significantly with age. This finding suggests that neurodegeneration has to be extensive to cause functional disturbance and clinical symptoms. Moreover, we investigated the correlation between AD related pathology in cortical biopsies, the AD / cerebrospinal fluid (CSF) biomarkers and the Mini Mental State examination (MMSE) scores in a cohort of idiopathic Normal Pressure Hydrocephalus (iNPH) patients. We demonstrated that AD/ CSF biomarkers and MMSE scores reflect AD pathology in the cortical biopsies obtained from iNPH patients. In conclusion, this study shows that the altered proteins associated with neurodegeneration are frequently seen in the brain tissue of cognitively unimpaired aged subjects. This fact should be considered while developing diagnostic biomarkers for identification of subjects at early stages of the disease, in order to introduce therapeutic intervention prior to the occurrence of significant cognitive impairment.
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Bajaj, Sahil, Anna Alkozei, Natalie S. Dailey, and William D. S. Killgore. "Brain Aging: Uncovering Cortical Characteristics of Healthy Aging in Young Adults." FRONTIERS MEDIA SA, 2017. http://hdl.handle.net/10150/626429.
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Despite extensive research in the field of aging neuroscience, it still remains unclear whether age related cortical changes can be detected in different functional networks of younger adults and whether these networks respond identically to healthy aging. We collected high-resolution brain anatomical data from 56 young healthy adults (mean age = 30.8 +/- 8.1 years, 29 males). We performed whole brain parcellation into seven functional networks, including visual, somatomotor, dorsal attention, ventral attention, limbic, frontoparietal and default mode networks. We estimated intracranial volume (ICV) and averaged cortical thickness (CT), cortical surface area (CSA) and cortical volume (CV) over each hemisphere as well as for each network. Averaged cortical measures over each hemisphere, especially CT and CV, were significantly lower in older individuals compared to younger ones (one-way ANOVA, p < 0.05, corrected for multiple comparisons). There were negative correlations between age and averaged CT and CV over each hemisphere (p < 0.05, corrected for multiple comparisons) as well as between age and ICV (p = 0.05). Network level analysis showed that age was negatively correlated with CT for all functional networks (p < 0.05, corrected for multiple comparisons), apart from the limbic network. While age was unrelated to CSA, it was negatively correlated with CV across several functional networks (p < 0.05, corrected for multiple comparisons). We also showed positive associations between CV and CT and between CV and CSA for all networks (p < 0.05, corrected for multiple comparisons). We interpret the lack of association between age and CT of the limbic network as evidence that the limbic system may be particularly resistant to age-related declines during this period of life, whereas the significant age-related declines in averaged CT over each hemisphere as well as in all other six networks suggests that CT may serve as a reliable biomarker to capture the effect of normal aging. Due to the simultaneous dependence of CV on CT and CSA, CV was unable to identify such effects of normal aging consistently for the other six networks, but there were negative associations observed between age and averaged CV over each hemisphere as well as between age and ICV. Our findings suggest that the identification of early cortical changes within various functional networks during normal aging might be useful for predicting the effect of aging on the efficiency of functional performance even during early adulthood.
4
Jonasson, Lars. "Aerobic fitness and healthy brain aging : cognition, brain structure, and dopamine." Doctoral thesis, Umeå universitet, Diagnostisk radiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-139056.
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Background: Performing aerobic exercise and maintaining high levels of aerobic fitness may have positive effects on both brain structure and function in older adults. Despite decades of research however, there is still a rather poor understanding of the neurocognitive mechanisms explaining the positive effects of aerobic exercise on cognition. Changes in prefrontal gray matter as well as dopaminergic neurotransmission in striatum are both candidate neurocognitive mechanisms. The main aims of this thesis are: 1. To investigate the effects of aerobic exercise and fitness on cognition and magnetic resonance imaging (MRI) derived gray matter volumes using data from a 6 month physical exercise intervention in older adults (Study I). 2. To simulate the effect of atrophy in longitudinal positron emission tomography (PET) which could pose a challenge to interpreting changes in longitudinal PET imaging (Study II). 3. To study the influence of aerobic exercise and fitness on the dopamine D2-receptor (D2R) system in striatum using [11C]raclopride PET as a potential mechanism for improved cognition (Study III). Results: In Study I, aerobic exercise was found to improve cognitive performance in a broad, rather than domain-specific sense. Moreover, aerobic fitness was related to prefrontal cortical thickness, and improved aerobic fitness over 6 months was related to increased hippocampal volume. In Study II, we identified areas in the striatum vulnerable to the effect of shrinkage, which should be considered in longitudinal PET imaging. Finally, in Study III, the effect of being aerobically fit, and improving fitness levels was found to impact dopaminergic neurotransmission in the striatum, which in turn mediated fitness-induced improvements in working memory updating performance. Conclusion: The findings in this thesis provide novel evidence regarding the neurocognitive mechanisms of aerobic exercise-induced improvements in cognition, and impacts the interpretation of longitudinal PET imaging. Performing aerobic exercise and staying aerobically fit at an older age have positive effects on cognition and brain systems important for memory and cognition. Specifically, fitness-induced changes to the dopaminergic system stands out as one novel neurocognitive mechanism explaining the positive effects of aerobic fitness on working-memory performance in healthy older adults.
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Fox, Geoffrey Arthur. "Effects of aging on functions of the prefrontal cortex." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050112.155754/index.html.
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Robinson, Amy Ann. "Quantification of brain-derived neurotrophic factor expression in the aging monkey brain." Thesis, Boston University, 2013. https://hdl.handle.net/2144/11035.
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Thesis (Ph.D.)--Boston UniversityWhile early studies of normal aging largely focused on the loss of neurons as a basis of cognitive aging, current studies of both aging humans and the rhesus monkey model of normal aging demonstrate that forebrain neurons are largely preserved. Instead, MRI and electron microscopic analyses show that age-related changes in the white matter are good predictors of cognitive impairment. White matter changes include an increase in damaged myelin sheaths as well as a loss of myelinated fibers. To explore potential causes of the white matter alterations, the expression of genes related to myelination and axonal survival were examined revealing age-related alterations in the expression of 9 genes in grey matter and 7 in subcortical white matter of the inferior parietal lobule (IPL). Four were selected for further analysis. Of these, brain-derived neurotrophic factor (BDNF) had a statistically significant decrease in expression in the cortical grey matter of the IPL at both the level of gene expression and of protein expression. In 27 male and female rhesus monkeys ranging from young to old, the precursor form of BDNF (proBDNF) was significantly decreased while the mature form was preserved. In order to understand the localization of the age-related decline in proBDNF, immunohistochemical reactivity was quantified in the IPL and in the hippocampus. In the IPL there was a significant decrease in total immunohistochemical reactivity. Further analysis showed that there was an increase in the number of proBDNF positive somata while there was no change in the smaller extrasomal puncta. This increase in cell bodies expressing proBDNF despite the age-related decrease in total proBDNF immunohistochemical density suggests disruption of post-translational processing and/or transport out into the processes. In contrast to the IPL, there was no change in proBDNF density in the hippocampus with age. However, in the hippocampus but not the IPL, proBDNF immunohistochemical reactivity was sexually dimorphic with higher levels in the female monkeys compared to males. While the significance of the change in proBDNF levels for myelin damage is unclear, alteration in this neurotrophin may play a role in the axon loss that accompanies myelin degradation.
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Higaki, Sayuri. "Molecular aspects of brain aging in female macaques." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157838.
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Klein, Martin. "Cognitive aging, attention, and mild traumatic brain injury." Maastricht : Maastricht : Neuropsych Publishers ; University Library, Maastricht University [Host], 1997. http://arno.unimaas.nl/show.cgi?fid=5810.
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Halfmann, Kameko Mae. "Emotion and decision-making in the aging brain." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1617.
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Natural aging leads to substantial brain changes. These biological changes can, and often do, precede changes in affect, cognition, and behavior. Even subtle changes, for example in affective experience, can create problematic outcomes in day-to-day emotion regulation and decision-making. For example, poor emotion regulation may lead an individual to fall prey to an emotionally potent scam. Similarly, an overly positive individual may not fully attend to or consider potentially negative future outcomes when faced with a decision. This work characterizes changes in affect across the lifespan, and how affect corresponds to brain function, as indexed by the blood oxygen dependent signal, during tasks taxing emotion regulation and decision-making functions. I predicted that age would correlate with greater positive relative to negative emotions and with a more global (i.e., less specific and less complex) representation of emotions. The former predicted pattern indicates increased "affective optimization" and the latter indicates reduced "affective complexity." I predicted that affective optimization and complexity would correlate with brain function during emotion regulation and decision-making. I used time-based experience sampling, self-reported affect, implicit measures of affect, and performance based measures of affect to determine the associations between age and affective optimization and complexity. Results show that age negatively correlates with affective complexity. Specifically, older age was associated with less negative affect complexity, less positive emotion regulation, less affective awareness. Also, older age corresponded to lower levels of negative affect, as indexed by their experiences and an implicit measure of affect. Next, I examined emotion regulation using a cognitive reappraisal task. I found that older age was associated with less successful reappraisal of negative and positive affect. I also found individual differences in the ventromedial prefrontal cortex among older adults during emotion regulation. Lastly, I examined decision-making patterns using an intertemporal choice task. I found that younger adults’ experienced affect aligned more closely with their decision patterns. Among older adults, affective acceptance correlated with individual differences in the striatum and insula. Taken together, these results support the idea that lower levels of affective competence, rather than higher levels, characterize older age. Also, individual differences in affect parallel individual differences in brain function in the somatic marker circuitry. This suggests possible deficits in interpreting visceral information important to emotion regulation and decision-making. The findings from this work will be important for understanding why some older adults are more susceptible to scams, fraud, and decision-making problems.
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Huang, Jing [Verfasser]. "Differential Aging effects on visuomotor control : evidence for an adaptive aging brain / Jing Huang." Gießen : Universitätsbibliothek, 2019. http://d-nb.info/1174938846/34.
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Apte, Vaijayanti. "Brain-reactive antibodies: molecular specificity and relationship to biological aging." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc798378/.
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Brain-reactive antibodies (BRA) increase in frequency with age in several mammalian species and may be involved in the pathogenesis of age-related dementia. In this experiment, the molecular specificity of BRA in mouse sera was determined using an immunoblot assay, and the relationship of BRA to longevity was studied by comparing the rate of formation of specific BRAs in diet restricted C57BL/6NNia, B6D2F1/NNia, and DBA/2NNia, genotypes which differ markedly in life-span.
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Richards, Brian. "The effects of aging and mild traumatic brain injury on neuropsychological performance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ59153.pdf.
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Chiu, Pui-wai, and 趙沛慧. "¹H and ³¹P brain magnetic resonance spectroscopy in aging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47170505.
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Magnetic Resonance Spectroscopy (MRS) was used to study the relationship between brain regional concentrations of metabolites and normal aging in Chinese. Our goal in this study is to create a database of normal aging and hence enhance further understanding on the degenerative process leading to dementia and related neurodegenerative diseases.
Thirty cognitively normal healthy volunteers of age 22-82 years were recruited and the bias on gender effect in data sampling was minimized by recruiting 15 females and 15 males. In the first part of the study, 1H MRS was obtained using single-voxel-spectroscopy (SVS). Offline software java-based version of Magnetic Resonance User Interface (jMRUI) was employed for data analysis. Cerebrospinal fluid was normalized using software voxel based morphormetry (VBM). Brain morphometry data was also analyzed. Brain metabolites choline (Cho), creatine (Cr) and N-acetyl aspartate (NAA) were quantified using internal water as reference. It was found that brain metabolite concentrations of Cr, Cho and NAA increase significantly with age. Gender effect on metabolite concentrations were also discovered, being higher in the female group. For brain morphometry, white matter and grey matter volumes and fractions all reveal a siginificant negative correlation with age, whereas CSF volume and fraction show a significant positive correlation with age. Gender effect was found on grey matter, white matter and intracranial volume, being higher in the male group.
In the second part of the study, 31P SVS MRS was performed on the same population of volunteers. jMRUI was also employed for data analysis. Metabolic ratios were obtained. Similar to the 1H MRS study, apart from creating a database in studying normal aging, an additional aim of this 31P MRS study is to correlate with 1H MRS and assist in interpreting the corresponding metabolic activity. Brain metabolite concentrations were found to increase significantly with age. The increase of PCr (phosphocreatine)/Ptot (total phosphorus content) in posterior cingulate suggests lower metabolic activity throughout the course of aging. The strong evidence of PDE (phosphodiester) increase with age in left hippocampus proposes the fact that phospholipid membrane breakdown will be enhanced by aging.
In conclusion, MRS can act as a non-invasive tool to study aging at molecular level. Metabolite levels are significant means to investigate the metabolic change in the human brain during the process of aging as the variations in metabolite levels are believed to be footprints of biochemical changes.published_or_final_version
Diagnostic Radiology
Master
Master of Philosophy
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Ferron, Danielle Carleton University Dissertation Psychology. "Changes with aging in right hemisphere activation as reflected in bimanual and dihaptic task performance." Ottawa, 1992.
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Piyanova, Anastasia [Verfasser]. "The role of endocannabinoid system in brain aging / Anastasia Piyanova." Bonn : Universitäts- und Landesbibliothek Bonn, 2012. http://d-nb.info/1044081406/34.
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Gouda, Mazen M. "Axon Initial Segment Integrity in Aging and Traumatic Brain Injury." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5993.
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According to the Center for Disease Control’s (CDC) report to the Congress, there are 2.2 million emergency department visits; 80,000 hospitalizations; and 50,000 deaths each year due to traumatic brain injury. Adults 65 years and older account substantially for the majority of the hospitalization and deaths. Over 70% of the traumatic brain injuries of the older adults are classified as mild to moderate; however, even with these milder injuries, older adults present with a significantly higher morbidity and mortality compared to all other age groups (LeBlanc et al., 2006). With that in mind, it seems essential to develop a deeper understanding of the causes behind higher mortality and morbidity of traumatic brain injury in the elder population. It is well documented that increased age is accompanied by increased CNS inflammation. Recently, our laboratory showed that inflammation drives brain pathology. Specifically, we reported that the axon initial segment of cortical neurons was structurally and functionally compromised in an inflamed CNS environment. With this in mind, we proposed that age-related inflammation predisposes that brain to exacerbated pathologic consequence. To test this hypothesis, we administered a mild to moderate central fluid percussion brain injury in aged and young adult mice. Using immunocytochemical labeling against the axon initial segment protein ankyrinG combined with laser scanning confocal microscopy, we quantitatively compared axon initial segment number and length between age groups and within age groups with and without injury. Additionally, we also quantified global axonal pathology by immunolabeling for amyloid precursor protein (APP) positive swelling as an indicator of compromised axonal transport. We proposed that ankyrinG labeling will be both reduced in the aged injured mice compared against aged uninjured, young adult injured and young adult non-injured. We observed a significant increase in APP accumulations due to injury independent of aging, and due to aging independent of injury. No significant changes in the effect of injury between young and aged injured mice were observed. Although AIS length was not altered between age groups following injury, our results demonstrate that the elderly population presents with significantly shorter initial segments. The consequence of this shortening is not clear but may reflect compensatory changes in the brain to maintain homeostasis.
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Zhang, Linda, and 張達. "Using structural and functional MRI to assess the effects of ethnicity on healthy ageing in the human brain." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/212626.
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In the last decade, several large multi-institutional neuroimaging studies have emerged, the chief amongst them being the Alzheimer's Disease Neuroimaging Initiative (ADNI). The data obtained from these studies are free to access for researchers, and are an invaluable resource in areas where getting a large enough cohort takes too long or becomes too expensive to fund. However, one should proceed with caution as the sample consists mostly of highly educated American Caucasians, reducing its generalisability to other countries. For those who have an interest in cross-ethnicity differences however, the ADNI dataset is ideal for this purpose.
This thesis begins with a cross-sectional look at cognitively normal, elderly Hong Kong Chinese subjects and matched ADNI Caucasian ones. When comparing total cortical grey matter volumes and the summed volumes of cortex that are often associated with Alzheimer's disease, it was found that Chinese subjects had significantly smaller cortical volumes than American Caucasians, even after adjusting for brain volume, despite having similar cognitive test scores. Unable to control for extrinsic factors such as environment and culture, however, no strong conclusions could be made.
The second study of this thesis consists of a replication of the first, this time using American Chinese and American Caucasian subjects, all long-time residents of San Francisco. The same results were found regarding total cortical grey matter volume, leading to the implication that the Chinese population have inherently smaller cortices than Caucasians, but with no obvious cognitive detriment.
Having found that ethnicity can have an effect on brain structure, the focus then shifts to how the brain changes during healthy ageing. The concept of healthy ageing has been gaining in popularity in recent years, especially as more and more age-related diseases are being thought of as "pathological ageing". In order to help diagnose and monitor diseases related to ageing, it is therefore important to understand the trajectory and effects of normal ageing. As such, a pilot fMRI study was conducted to try and see how attention and increased vulnerability to interference from presented stimuli changed with age.
The results from the pilot study matched generally well with the literature and opens up the door towards using cognitive paradigms in neuroimaging to act as baseline markers of cognitive function, which can then be correlated with other measures to paint a more detailed portrait of the healthy ageing brain.published_or_final_version
Diagnostic Radiology
Doctoral
Doctor of Philosophy
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Driscoll, Ira, and University of Lethbridge Faculty of Arts and Science. "The aging hippocampus : a multilevel analysis in the rat." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005, 2005. http://hdl.handle.net/10133/12.
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The purpose of the current thesis was twofold: (1) to examine various factors that might be contributing to age-related learning and memory deficits specifically related to the hippocampus, and (2) to validate our rat model of aging, employing a multilevel analysis. We found age-related deficits on both spatial and non-spatial hippocampus-dependent taks that were accompanied by structural alterations observed in vivo (volune, but not neuronal metabolic function) and post mortem (neuronal density and neurogenesis, but not synaptic or mitochondrial density). Furthermore, our results suggest that the observed hippocampal structural changes, named decreased volume and neurogenesis, predict learning and memory deficits, and both can be accounted for by neurogenic reduction. In addition, the above-mentioned pattern of age-related deficits closely resembles that seen in humans, suggesting the present rat version of aging to be a very useful model for investigating hippocampal aging in humans.iii, 236 leaves : ill. (some col.) ; 29 cm.
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Zhang, Yi. "Brain MRI and CT morphology in healthy aging and Alzheimer's disease." Stockholm, 2010. http://diss.kib.ki.se/2010/978-91-7409-791-7/.
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Solé, Padullés Cristina. "Function and brain structure in aging with and without cognitive impairment." Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/2705.
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L'interès general d'aquest projecte de tesi doctoral es centra en l'estudi dels patrons d'activació cerebral subjacents a l'envelliment cognitiu, tant en condicions clíniques normals com patològiques (Alteració cognitiva relacionada amb l'edat, alteració cognitiva lleu o Alzheimer inicial). Per aquest motiu hem empleat la tècnica de la RMf i hem estudiat com diferents variables intrínseques i extrínseques als individus estudiats influeixen la seva activació cerebral.En un primer estudi ens vam plantejar l'estudi de les relacions entre el cervell i conducta en subjectes envellits amb queixes subjectives de memòria, segons criteris de Levy (1994). Així, el primer objectiu era estudiar com una tècnica capaç de modificar l'excitabilitat cortical de forma transitòria, l'estimulació magnètica transcranial (EMT) podia modular l'activació cerebral observada amb RMf i de retruc influir l'execució d'una tasca d'aprenentatge.
Posteriorment, després d'haver observat un efecte facilitador de l'EMT en el rendiment en memòria d'aquest subjectes vam voler tenir en compte com el fet de ser portador de la variant ε4 del gen de l'apolipoproteïna E (APOE), podria modular l'activació cerebral després d'una sessió d'EMT. Aquest al.lel s'ha relacionat amb disfuncions de tipus tant metabòlic com d'activació cerebral durant la realització de tasques cognitives, similars als observats en la MA, per tant l'objectiu d'aquest estudi era veure com dos factors, un intrínsec (ser portador de ε4) i una altre extrínsec (EMT), ambdós amb un efecte conegut en l'activació cerebral s'influïen mútuament per modular els patrons funcionals i com això afectava en últim terme l'execució en memòria.
Seguint amb l'estudi de les diferències funcionals entre portadors ε4 i no ε4, ens va interessar determinar els patrons de connectivitat cerebral de l'hipocamp en aquests dos grups de subjectes, amb queixes de memòria, durant l'execució d'una tasca de memòria associativa.
Finalment, després d'haver observat les diferents graus de manifestacions clíniques en subjectes amb una neuropatologia equiparable o les diferències en patrons d'activació causades per un emergent patologia cerebral vam considerar l'estudi d'aquestes diferències individuals (descrites com a factors de reserva cognitiva) per investigar els seus efectes en la funció i estructura cerebral de subjectes envellits pertanyents a diferents categories clíniques (envelliment normal, ACL i MA).
En resum, els objectius específics de la tesi es podrien concretar en els següents punts:
1) Estudiar els efectes de l'Estimulació Magnètica Transcranial (EMT) en l'activitat cerebral i el rendiment cognitiu durant una prova d'aprenentatge visual en una mostra de pacients envellits amb queixes de memòria.
2) Estudiar els efectes de la interacció entre l'EMT i el genotip de l'APOE en una mostra de pacients amb queixes de memòria.
3) Estudiar com el fet de tenir un determinat genotip del polimorfisme de l'APOE podria afectar els patrons d'activitat i connectivitat cerebrals mentre es realitza una tasca d'aprenentatge en pacients amb alteració cognitiva relacionada amb l'edat.
4) Estudiar la influència de les variables de reserva cognitiva en l'estructura cerebral per tal de provar la hipòtesi de la reserva cerebral, així com investigar com un determinat nivell de reserva cognitiva pot influenciar els patrons d'activitat cerebral per tal d'explorar els models actius (compensació) en l'envelliment normal, ACL i MA inicial.
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Pilon-McDonald, Lucille. "Aging parents of adult children with acquired brain injury : future need." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33465.
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This thesis explores the experiences of aging parents caring for adult children with acquired brain injury regarding future care needs. Seven parents representing four adult disabled children, were individually interviewed using the Family Support and Coping Interview. The parents then participated in three groups sessions to discuss the commonality of 'never-ending' parenthood. The parents, who average 70.9 years of age, have been sole caregivers for middle-aged children. Their displaced life cycle responsibilities, their vision of a solution and the need to socially publicize their predicament were major themes requiring advocacy with policy makers and government funders. Research into the care of those who cannot manage independent living is imperative, particularly as social thinking and fiscal policies espouse the benefits of the autonomous family.
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Shao, Changxing. "OXIDATIVE STRESS AND MITOCHONDRIAL DYSFUNCTION IN TRAUMATIC BRAIN INJURY IN AGING." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/533.
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Traumatic brain injury (TBI) is a prominent disease in developed countries, and age is an important factor in functional outcome. Although aged patients typically show diminished recovery compared to young patients, and have higher mortality and morbidity following TBI, the mechanism is not well understood. To date, there is no effective therapeutic for TBI. Previous studies indicate a secondary injury in TBI begins immediately after impact, and is likely the major contribution to delayed neuron dysfunction and loss. Studies also suggest mitochondrial dysfunction and increased free radical species (ROS) production following TBI may play a key role in the process. To evaluate oxidative damage following TBI, especially in aging, young (3 months), middle aged (12 months) and aged (22 months) Fisher-344 rats were subjected to a unilateral controlled cortical impact (CCI) injury, and tissue sparing, 4-hydroxynonenal (HNE) and acrolein levels, and antioxidant enzyme activities, and DNA oxidative damage were measured. In order to evaluate changes in mitochondria following TBI, mitochondrial protein levels were investigated using young adult animals. To evaluate a potential therapeutic for TBI, the effect of creatine on oxidative damage was evaluated. These studies show an age dependent increase of oxidative damage following TBI, demonstrated by increased levels of 4-HNE, acrolein and 8-hydroxyguanine. Middle aged and aged animals showed increased tissue loss compared to young animals 7 days post injury. Mitochondrial proteins involved in the respiratory chain, carrier proteins and channel proteins were significantly decreased 24 h post injury in ipsilateral cortex, but increased in both ipsilateral and contralateral hippocampus. To study potentially protective compounds in TBI, animals were fed with creatine two weeks before TBI and showed less oxidative damage and increased antioxidant capacity, which suggests creatine may be a potential drug for clinical treatment of TBI. The work described in this dissertation is the first to show increased oxidative damage and diminished antioxidant capacity in TBI in aging. The study of mitochondriafollowing TBI using quantitative proteomics is also the first time to show multiple mitochondrial proteins change following TBI. These data are also the first to show creatine can increase antioxidant defenses. These studies contribute to our understanding the mechanisms of secondary injury in TBI in aging.
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Errangi, Bhargav Kumar. "A diffusion tensor imaging study of." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28156.
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Thesis (M. S.)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: James K. Rilling; Committee Chair: Xiaoping Hu; Committee Member: Shella Keilholz; Committee Member: Todd M. Preuss.
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Pinto, Maíra Siqueira. "Study of human structural brain connectivity in healthy aging based on tracts." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-16042018-151221/.
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The human brain changes in a complex and heterogeneous way throughout life, the normal aging process is associated to significant alterations in the axonal connections. In this study, we evaluated the age-related changes in physical parameters associated with the brain white and gray matter integrity in healthy subjects, as well as the possible correlation between them in specific tracts. Structural images (1 mm isotropic) and diffusion weighted images (2 mm isotropic, b = 1000 s /mm2) of 158 healthy individuals aged between 18 and 83 years were retrospectively collected at the Clinics Hospital of Ribeirao Preto, after their acquisition in a 3T MR scanner. From the structural images, the cortical thickness was estimated and the age effect was evaluated in several regions based on the Atlas of Destrieux. The diffusion-weighted images were processed to characterize the intravoxel diffusion using two models: diffusion tensor (DT) and constrained spherical deconvolution (CSD). Fractional anisotropy (FA) and apparent density of fiber (AFD) maps were estimated and used in statistical group analysis between the three groups separated by age. The most relevant brain tracts were segmented by three procedures: manually, automatically with a specific tool and based on automatic segmented cortical regions. Physical parameters of diffusion (anisotropy and diffusivities) were evaluated in the segmented tracts to determine the age-related changes. The connectome analysis based on two cortical parcellations was performed to evaluate the age effect on characteristic structural brain network parameters. The tract-cortical relationship was evaluated considering the anisotropy of each tract and the thickness of the cortical areas at the end of the corresponding tract. Further analysis was performed to evaluate a possible association of structural and functional connectivity in the corpus callosum (CC). There was significant cortical thinning in 88.5% of the regions during life (p <0.05, corrected for multiple comparisons); the frontal region was the most affected in the initial aging (after 40 years), and the occipital and temporal regions in the elderly (after 60 years). Similarly, the group analysis demonstrated a global pattern of reduction of FA and AFD in the white matter, with a higher rate of degradation of integrity from the sixth decade of life. The manual selection of tracts from the DT model proved to be the most reliable methodology in the precise definition of the tracts for our data. Following this methodology, analysis of anisotropy and diffusion parameters also indicated degeneration of white matter in normal aging in all studied brain tracts and corroborated to the antero-posterior gradient of degeneration in the CC. Fornix was the most affected tract bilaterally, with a 3.5% reduction and an increase of 4% per decade in these parameters, respectively; followed by CC. In the evaluation of the age effect on the connectome estimates, regardless of diffusion model and cortical atlas, there was a decrease in global efficiency, number of connections and local efficiency with aging, mainly in the prefrontal, temporal and parietal and its connections. In the tract-cortical analysis, cortical regions connected by tracts demonstrated similar thinning patterns for the majority of tracts, and a significant relation between mean cortical thinning rate and FA/MD alteration rates were found. In all evaluated tracts, age was the main effect controlling diffusion parameters alterations; there were no direct correlations with cortical thickness for the majority of tracts. Only for the fornix, the values of FA and MD showed significant correlation with the cortical thickness of the subcallosal gyrus in both hemispheres during aging (p <0.05 corrected). For the other tracts, CC, Inferior Longitudinal Fasciculus, Uncinated Fasciculus, Inferior Fronto-occipital Fasciculus, Corticospinal Tract, Cingulum and Arcuate Fasciculus, age was the main effect controlling alterations in the parameters, but there were no direct correlations between FA and MD and cortical thickness during the aging process.O cérebro humano muda de forma complexa e heterogênea ao longo da vida, o processo de envelhecimento normal tem associado significativas alterações nas conexões axonais. Neste estudo, avaliamos as mudanças relacionadas à idade em parâmetros físicos associados à integridade das substâncias branca e cinzenta cerebral em sujeitos saudáveis, assim como a possivel correlação entre eles em tratos específicos. Imagens estruturais (1 mm isotrópica) e imagens ponderadas em difusão (2 mm isotrópica e b=1000 s/mm2) de 158 indivíduos saudáveis entre 18 a 83 anos foram coletadas retrospectivamente no Hospital das Clinícas de Ribeirão Preto, após sua aquisição em aparelho de ressonância magnética de 3 Teslas. A partir das imagens estruturais, a espessura cortical foi estimada e o efeito de idade nela foi avaliado em diversas regiões tomando com base o atlas de Destrieux. As imagens ponderadas em difusão foram processadas para caracterizar a difusão intravoxel utilizando dois modelos: tensor de difusão (DT) e deconvolução esférica restrita (CSD). Mapas de anisotropia fracionada (FA) e densidade aparente da fibra (AFD) foram estimados e usados em analise estatistica de três grupos separados por faixa etária. Os tratos cerebrais mais relevantes foram segmentados por tres procedimentos: manualmente, automaticamente com uma ferramenta especifica e com base em regiões corticais automaticante segmentadas. Parâmetros físicos de difusão (anisotropia e difusibilide) foram avaliados nos tratos segmentados para determinar as alterações relacionadas à idade. A análise de conectoma baseada em dois parcelamentos corticais foi realizada para avaliar também o efeito da idade em parâmetros caracteristicos da rede estrutural cerebral. A relação trato-cortical foi avaliada considerando a anisotropia de cada trato e as espessuras das áreas corticais nas extremidades do trato correspondente. Uma análise adicional foi realizada para avaliar uma possivel associação de onetividades estrutural e funcional no corpo caloso (CC). Houve afinamento cortical significativo em 88,5% das regiões durante a vida (p <0,05, corrigido); a região frontal foi a mais afetada no envelhecimento inicial (após 40 anos), e as regiões occipital e temporal nos idosos (após 60 anos). Similarmente, a análise de grupo demonstrou um padrão global de redução de FA e AFD na substância branca, com uma maior taxa de degradação de integridade a partir da sexta década de vida. A seleção manual de tratos baseada no modelo de DT mostrou-se a metodologia mais confiavél na precisa definição dos tratos nos nossos dados. Seguindo essa metodologia, a análise dos parâmetros de anistropia e difusão também indicou degeneração de substância branca no envelhecimento normal em todos os tratos cerebrais estudados e corroborou o gradiente ântero-posterior de degeneração no CC. O fornix foi o trato mais afetado bilatreamente com redução de 3.5% e aumento de 4% por década nesses parâmetros, respectivamente; seguido do CC. Na avaliação do efeito da idade nas estimativas do conectoma, independentemente do modelo de difusão e do atlas cortical usado, houve uma diminuição da eficiência global com o envelhececimento, do número de conexões e da eficiência local, principalmente nas regiões pré-frontal, temporal e parietal e suas conexões. Nas análises trato-corticais, as regiões corticais conectadas por tratos mostraram padrões de afinamento similares para a maioria dos tratos, e uma correlação significativa entre a taxa média de afinamento cortical e as taxas de alteração de FA e difusibilidade média (MD) foram encontradas. Em todos os tratos avaliados, a idade foi o principal efeito controlando das alterações dos parâmetros de difusão; não houve correlações diretas com espessura cortical para a maioria dos tratos. Somente para o fornix, os valores de FA e MD mostraram correlação com a espessura cortical do giro subcalosal (parcelamento de Destrieux) em ambos os hemisférios durante o envelhecimento (p <0,05 corrigido). Para os outros tratos, CC, fascículo longitudinal inferior, fascículo uncinado, fascículo occipitofrontal inferior, trato cortico-espinal, parte cingulada do cíngulo e fascículo arqueado, a idade foi o principal efeito no controle das alterações dos parâmetros, mas não houve correlações diretas entre FA e MD e espessura cortical durante o processo de envelhecimento
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Zhang, Luduan. "QUANTIFYING BRAIN WHITE MATTER STRUCTURAL CHANGES IN NORMAL AGING USING FRACTAL DIMENSION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1126213038.
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Drake, Derek. "REST and the regulation of stress resistance, brain aging, and Alzheimer’s disease." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493396.
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Understanding how age-related stress in the brain is managed over a lifetime to maintain neuronal and cognitive function and prevent neurodegeneration will be critical for developing therapies to promote healthy aging. Here we show that repressor element 1-silencing transcription factor (REST) is induced in neurons of cognitively-intact aged individuals, but not those with Alzheimer’s disease (AD). REST protects against factors associated with AD, such as neuronal apoptosis and AD neuropathology, through direct binding and repression of pro-apoptotic genes and genes that contribute to AD neuropathology. REST nuclear levels in prefrontal cortex pyramidal neurons also correlate with increased AD age of onset and decreased AD neuropathology. REST protects against toxic insults associated with aging, such as oxidative stress. Moreover, REST regulates FOXO1, a fundamental regulator of the response to oxidative stress, to provide oxidative stress protection. REST and FOXO1 nuclear levels correlate in aging human cortical neurons. Furthermore, REST and FOXO1 expression are correlated with the expression of FOXO1-regulated genes that protect against oxidative stress in aged prefrontal cortex. REST also downregulates miR- 132 and miR-212, microRNAs that repress FOXO1 expression, and sensitize to oxidative stress. High levels of REST in the nucleus correlate with reduced longitudinal cognitive decline during aging. Moreover, REST nuclear levels account for a significant fraction of the variability of cognitive decline in the aging human population by a mixed model analysis. These results suggest that the neuroprotective function of REST is mediated, at least in part, through regulation of FOXO1 and miR-132/miR-212, and that REST is a critical determinant of stress resistance and cognitive preservation during aging.Medical Sciences
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Hanson, Krista D. "Relation of Physical Fitness to Brain Aging and Cognition in Older Adults." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/222574.
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Level of physical fitness may be an important factor influencing the effects of brain aging and age-related cognitive decline. Multiple measures of aerobic fitness were used in a cohort of healthy older adults 50-89 years of age to identify how individual differences in fitness relate to brain aging and age-associated cognitive decline. Healthy adults (n=123; 65 F and 58 M; mean ± sd age = 67.9 ± 10.0; Mini-Mental State Exam = 29.1 ± 1.2) were screened to exclude neurological, psychiatric, and medical illnesses that could affect cognitive function, including hypertension. The Scaled Subprofile Model (SSM) with voxel-based morphometry and Statistical Parametric Mapping version 8 (VBM; SPM8 Dartel) were performed on T1-weighted 3T volumetric magnetic resonance imaging (MRI) scans to identify a gray matter pattern associated with brain aging. Performance on aerobic fitness measures, assessed during a graded exercise treadmill test (GXT), was evaluated in relation to the age-associated MRI gray matter network pattern and indices of neuropsychological function. Multivariate SSM VBM network analysis identified a linear combination of patterns that predicted age (R² = 0.48, p = 8.71e-19). This combined pattern was characterized by reductions in bilateral lateral and medial frontal, parietal, lateral temporal, and cerebellar regions with relative preservations in thalamic, occipital, and medial temporal regions including the hippocampus. Higher expression of the age-related network pattern was associated with poorer performance on multiple fitness indices. The best combination of fitness measures in predicting brain aging included overall treadmill exercise time, ventilatory efficiency, and the difference between basal and maximal respiratory rate (p = 6.67e-7). A higher combined fitness index score related to brain aging was associated with better performance on measures of memory, executive function, and processing speed in this cohort (6.08e-9≤ p≤ 0.05). Those individuals with higher levels of aerobic fitness had lower expression of the gray matter brain aging pattern and better performance on measures of memory, executive function, and processing speed. Identifying those fitness indices that are the best predictors of brain aging and cognitive performance may aid efforts in developing and evaluating exercise based interventions for age-related cognitive decline.
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Majdi, Maryam. "Brain ageing : cognitive status and cortical synapses." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115704.
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This thesis focused on the spatiotemporal patterning of classical excitatory and inhibitory synaptic contacts accounting for the majority of cerebral cortical connections, in relation to ageing and cognitive status. These investigations tested the hypothesis that higher CNS functions depend on the balance between excitatory and inhibitory synaptic connections. Glutamatergic and GABAergic presynaptic bouton densities were determined in aged animals segregated according to their cognitive status into aged and cognitively unimpaired (AU) and aged and cognitively impaired (AI), using the Morris water maze. These two groups were compared in terms of behaviour and the pattern of excitatory and inhibitory synapses. It was evident that an excitatory and inhibitory presynaptic decline is associated with age-related cognitive impairments; whereby both glutamatergic and GABAergic boutons gradually diminish from young to AU to AI. Nevertheless, the balance between excitatory and inhibitory presynaptic inputs was maintained. To determine whether postsynaptic sites differed with respect to ageing and cognitive impairments, excitatory and inhibitory postsynaptic scaffold proteins were investigated in the same cohort of segregated aged animals. There was an imbalance in density ratio between immunoreactive sites of excitatory versus inhibitory postsynaptic scaffold proteins in AI animals. This resulted from a marked decrease in the density of excitatory postsynaptic sites. To further investigate ultrastructural aspects of excitatory synapses I carried out electron microscopical studies of cerebral cortex to measure the abundance of NR2 receptor subunits of the NMDA receptor- a receptor site directly associated with excitatory postsynaptic scaffold proteins. This study revealed that NR2 immunoreactive sites were largely preserved during age-related cognitive decline with an uneven profile distribution. Finally, protein expression of specific receptor subunits and key proteins representative of excitatory and inhibitory postsynaptic sites was investigated by semi-quantitative Western blot analyses in selected cortical areas. It was clear that many of these postsynaptic proteins are affected by age and cognitive status. The most striking change was a marked up-regulation in neuroligin-1 in AI animals, which may affect the delicate balance between excitatory versus inhibitory synaptic inputs. Another notable finding was the down-regulated expression of GluR2 receptor subunits in AI animals, which should have implications for neuronal Ca2+ regulation. In conclusion, we have demonstrated the greater vulnerability of excitatory postsynaptic sites in aged and cognitively impaired animals.
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Stewart, Maureen. "The effects of age and education on selected cognitive tests: the trail making test, the digit symbol sub-test, and the finger tapping test." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1004601.
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Numerous studies have suggested that neuropsychological test performance is affected by demographic variables such as age and education. This study examined the effects of age and education on the Trail Making Test, the Digit Symbol Sub-Test, and the Finger Tapping Test in a non-clinical sample of community dwellers with a relatively low level of education (8 to 12 years) in South Africa. The sample consisted of 161 participants across six age groups: 20-39, 40-59, 69-69, 70-79, 80-89 and 90-95 years. Results were examined for mean age effects and variability trends. Highly significant age effects were present across the age groups for all tests, however, there was no uniform pattern of variability across the tests. The Digit Symbol Substitution Test and the Finger Tapping Tests showed a pattern of increasing variability with increasing age, followed by a decrease in very old age while no trend was evident for the Digit Symbol extensions (the Immediate and Delayed Recall tests). The Trail Making Test, Parts A and B, showed a consistent trend of increasing variability across the age groups. Data from the present study was compared with existing data from two relatively high education samples, with equivalent age groupings, to examine education effects. Results showed an education effect for all tests with the high education groups outperforming the low education groups. Although the effects of education became less potent with advancing age, the mean performance of the oldest (80-89 years) high education age group was superior to that of the equivalent low education age group. Comparison of variability trends across both samples showed that the highest variability (the shuttle bulge) was present at the same point along the age axis, or at a later point, for the low education group, as that for the high education group. This finding is inconsistent with Jordan's (1997) 'shuttle model of variability' which predicts an earlier occurrence of the shuttle bulge (left shuttle shift effect) for a low education sample. This study demonstrated that performance on neuropsychological tests is influenced by age and education and highlighted the dangers inherent in unquestionably applying norms, which have not been corrected for age and education, when assessing the older adult.
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Ziegler, David A. (David Allan). "Cognition in healthy aging and Parkinson's disease : structural and functional integrity of neural circuits." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68169.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Brain and Cognitive Sciences, September 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
"September, 2011." Cataloged from student submitted PDF version of thesis.
Includes bibliographical references.
This dissertation documents how healthy aging and Parkinson's disease (PD) affect brain anatomy and physiology and how these neural changes relate to measures of cognition and perception. While healthy aging and PD are both accompanied by a wide-range of cognitive impairments, the neural underpinnings of cognitive decline in each is likely mediated by deterioration of different systems. The four chapters of this dissertation address specific aspects of how healthy aging and PD affect the neural circuits that support sensory processes and high-level cognition. The experiments in Chapters 2 and 3 examine the effects of healthy aging on the integrity of neural circuits that modulate cognitive control processes. In Chapter 2, we test the hypothesis that the patterns of age-related change differ between white matter and gray matter regions, and that changes in the integrity of anterior regions correlate most strongly with performance on cognitive control tasks. In Chapter 3, we build upon the structural findings by examining the hypothesis that age-related changes in white matter integrity are associated with disrupted oscillatory dynamics observed during a visual search task. Chapter 4 investigates healthy age-related changes in somatosensory mu rhythms and evoked responses and uses a computational model of primary somatosensory cortex to predict the underlying cellular and neurophysiolgical bases of these alterations. In contrast to the widespread cortical changes seen in healthy OA, the cardinal motor symptoms of PD are largely explained by degeneration of the dopaminergic substantia nigra, pars compacta (SNc). Cognitive sequelae of PD, however, likely result from disruptions in multiple neurotransmitter systems, including nondopaminergic nuclei, but research on these aspects of the disease has been hindered by a lack of sensitive MRI biomarkers for the affected structures. Chapter 5 presents new multispectral MRI tools that visualize the SNc and the cholinergic basal forebrain (BF). We applied these methods to test the hypothesis that degenerative processes in PD affect the SNc before the BF. This experiment lays important groundwork for future studies that will examine the relative contribution of the SNc and BF to cognitive impairments in PD.
by David A. Ziegler.
Ph.D.
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Lee, Won Hee. "Molecular mechanisms of radiation-induced brain injury." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77254.
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Radiation therapy has been most commonly used modality in the treatment of brain tumors. About 200,000 patients with brain tumors are treated with either partial large field or whole brain irradiation every year in the United States. The use of radiation therapy for treatment of brain tumor, however, can subsequently lead to devastating functional deficits several months to years after treatment. Unfortunately, there are no known successful treatments and effective strategies for mitigating radiation-induced brain injury. In addition, the specific mechanisms by which irradiation causes brain injury in normal tissues are not fully understood. A deeper understanding of the molecular mechanisms underlying these phenomena could enable the development of more effective therapies to contribute to long-term disease suppression or even cure. Therefore,the primary goal of this research project was to determine the molecular mechanisms responsible for radiation-induced brain injury in normal tissues.
In the first study, the effects of whole brain irradiation on pro-inflammatory pathways in the brain were examined. Results demonstrated that brain irradiation induces regionally specific alterations in pro-inflammatory environments through activation of pro-inflammatory transcription factors (e.g., activator protein-1 (AP-1),nuclear factor-κB (NF-κB), and cAMP response element-binding protein (CREB)) and overexpression of pro-inflammatory mediators (e.g., tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1)) in brain. This study provides evidence for a differential induction of pro-inflammatory mediators in specific brain regions that have importance for the neurological/neuropathological consequences of irradiation.
In the second study, a mathematical model describing radiation-induced mRNA and protein expression kinetics of TNF-α in hippocampus was reconstructed. This study demonstrated that the reaction kinetic model could predict protein expression levels of TNF-α in cortex, suggesting that this model could be used to predict protein expression levels of pro-inflammatory mediators in other parts of the brain.
In the third study, the effects of aging on radiation-mediated impairment of immune responses in brain were examined. Results showed that radiation-induced acute inflammatory responses, such as overexpression of pro-inflammatory cytokines (e.g., TNF-α, IL-1β, and IL-6),adhesion molecules (e.g., intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin), chemokine MCP-1, and matrix metalloproteinase-9 (MMP-9), are significantly impaired in aged brain. This study suggests that reduced production of pro-inflammatory mediators in response to irradiation compromises the normal host defense mechanisms in damaged brain tissue and subsequently leads to impaired repair/remodeling responses in old individuals.
In the fourth study, the effects of irradiation on MMPs/tissue inhibitor of metalloproteinases (TIMPs) and extracellular matrix (ECM) degradation in brain were examined. Results demonstrated that whole brain irradiation induces an imbalance between MMPs and TIMPs expression, increases gelatinase activity, and degrades collagen type IV in the brain. This study suggests that a radiation-induced imbalance between MMP-2 and TIMP-2 expression may have an important role in the pathogenesis of brain injury by degrading ECM components of the blood-brain barrier (BBB) basement membrane.
In the fifth study, the effects of irradiation on angiogenic factors and vessel rarefaction in brain were examined. Results demonstrated that whole brain irradiation decreases endothelial cell (EC) proliferation, increases EC apoptosis, and differentially regulates the expression of angiogenic factors such as angiopoietin-1 (Ang-1), Ang-2, Tie-2, and vascular endothelial growth factor (VEGF) in brain. This study suggests that radiation-induced differential regulation of angiogenic factors may be responsible for vessel rarefaction.
In summary, the results from these studies demonstrated that whole brain irradiation induces brain injury by triggering pro-inflammatory pathways, degrading extracellular matrix, and altering physiologic angiogenesis. Therefore, this work may be beneficial in defining a new cellular and molecular basis responsible for radiation-induced brain injury. Furthermore, it may provide new opportunities for prevention and treatment of brain tumor patients who are undergoing radiotherapy.Ph. D.
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Warsch, Jessica. "Subclinical Vascular Brain Damage, Vascular Risk Factors, and Depression in Successful Cognitive Aging." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/644.
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Currently, about one in every eight Americans is age 65 or older; by the year 2050, it will be one in five people. Given this graying of the population, research into successful aging is of increasing relevance. The question of how to precisely define successful aging, however, has not been completely answered. Likewise, the role of vascular risk factors, subclinical vascular brain damage, and other biopsychosocial characteristics in normal cognitive aging are not well understood. This Dissertation focused on the identification of some of the physiological, behavioral, and social risk factors that distinguish people able to maintain extraordinary health at an advanced age. Specifically, we aimed to create an ecologically valid definition of successful aging that incorporates both physical well-being and cognitive abilities, and to report the prevalence of successful cognitive aging in a population-based multi-ethnic cohort of older adults. We sought to describe how the prevalence varies by several sociodemographic and psychosocial determinants, and to investigate global vascular risk, depressive symptomatology, and MRI markers of subclinical vascular brain damage as correlates of successful cognitive aging. We observed the prevalence of successful cognitive aging to be 37% in the study sample (N=1,162) of a diverse racial/ethnic population in Northern Manhattan (NYC, NY). The prevalence decreased with increasing age; we did not observe any differences by racial/ethnic group, but did note a lower prevalence with lower socioeconomic status. Several social resources and self-reported quality of life were related to successful cognitive aging, and appeared more important than demographic variables alone. We found that the likelihood of successful cognitive aging decreases with increasing global vascular risk score, more severe depressive symptomatology, and greater white matter damage. The field of successful aging requires further study. Consideration of such biopsychosocial factors as socioeconomic status, social support, quality of life, and depressive symptoms alongside novel indicators of disease and disability including global vascular risk and white matter hyperintensity burden is essential. It may lead to a more robust definition of successful cognitive aging replete with opportunities to modify the aging process, as many of the factors investigated in this study are modifiable.
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Yero, Alexis D. "Memory, Processing Speed, and the Effects of Cognitive Exercise on the Aging Brain." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/3062.
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The purpose of the current study was to investigate, and expain, the effects of an intervention known as “The Five Task Approach” (TFTA); a cognitive intervention hereby utilized within the realm of the geriatric population, as a means of taxing and strengthening cortical areas associated with memory, and visual processing. This study revealed that even short-term exposure to cognitive activities, and therapeutic cueing known to tax areas connected to visual perception, may have an effect on one’s global cognition, generalized memory, and the accuracy of one’s visual perception. It was demonstrated that even brief cognitive intervention geared at taxing cortical areas associated with memory and visual processing, in conjunction with the therapuetic cueing utilized in this study, has the potential to significantly increase participant performance in terms of global cognitive function, including skills associated with executive functioning, working memory, visual processing, visual processing speed, auditory processing, and global cognitive status.
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Terwel, Dirk. "Vasopressin in the brain and plasma of the aging rat a radioimmunoassay study /." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1992. http://arno.unimaas.nl/show.cgi?fid=6502.
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Pudas, Sara. "Brain characteristics of memory decline and stability in aging : Contributions from longitudinal observations." Doctoral thesis, Stockholms universitet, Psykologiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-93026.
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Aging is typically associated with declining mental abilities, most prominent for some forms of memory. There are, however, large inter-individual differences within the older population. Some people experience rapid decline whereas others seem almost spared from any adverse effects of aging. This thesis examined the neural underpinnings of such individual differences by using longitudinal observations of episodic memory change across 15-20 years, combined with structural and functional magnetic resonance imaging of the brain. Study I found significant correlations between volume and activity of the hippocampus (HC), and memory change over a 6-year period. That is, individuals with decline in HC function also had declining memory. In contrast, Study II showed that successfully aged individuals, who maintained high memory scores over 15-20 years, had preserved HC function compared to age-matched elderly with average memory change. The successful agers had HC activity levels comparable to those of young individuals, as well as higher frontal activity. Study III revealed that individual differences in memory ability and brain activity of elderly reflect both differential age-related changes, and individual differences in memory ability that are present already in midlife, when age effects are minimal. Specifically, memory scores obtained 15-20 years earlier reliably predicted brain activity in memory-relevant regions such as the frontal cortex and HC. This observation challenges results from previous cross-sectional aging studies that did not consider individual differences in cognitive ability from youth. Collectively the three studies implicate HC and frontal cortex function behind heterogeneity in cognitive aging, both substantiating and qualifying previous results from cross-sectional studies. More generally, the findings highlight the importance of longitudinal estimates of cognitive change for fully understanding the mechanisms of neurocognitive aging.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.
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Platt, Thomas. "LEPTIN RESISTANCE INDUCED OBESITY AND DIABETES PROMOTE NEUROPATHOLOGICAL CHANGES IN THE AGING BRAIN." UKnowledge, 2014. http://uknowledge.uky.edu/biochem_etds/18.
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The aging brain is prone to the development of pathology and dementia. With a rapidly growing elderly population diagnoses of neurodegenerative diseases, such as Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Parkinson’s disease are on the rise. Additionally, diabetes and obesity are linked to an increased risk of dementia. The convergence of this increasingly aged population with the obesity and diabetes epidemic give rise to new concerns regarding the future of prevention and treatment of neurodegenerative diseases. Our lab has previously shown that leptin, an adipokine involved in signaling satiety to the hypothalamus, can modulate the generation of the amyloid beta (Aβ) peptide (a toxic peptide associated with neurologic disease) and attenuate hyperphosphorylation of the tau protein (another peptide prone to forming large insoluble structures causing neurodegeneration). From these studies we have elucidated that leptin resistant mice (which develop severe obesity and type-2 diabetes mellitus) with knock-in mutations for the amyloid precursor protein (APP) and presenilin-1 (PS1) genes develop extensive vascular pathology and cognitive impairments. Interestingly, these mice do not display increased levels of amyloid deposition in the brain. Additionally, increased tau phosphorylation occurs in these mice with leptin resistance. As a follow up to this study db mice were transduced, via adeno-associated virus, with the tau P301L mutant to induce the development of tangle pathology. These mice displayed no cognitive deficits, yet they displayed increases in both tau phosphorylation and tangle count within the hippocampus. Collectively, these studies indicate leptin resistance, obesity, and type-2 diabetes mellitus promote the development of cerebrovascular and neurofibrillary tangle pathologies associated with neurodegeneration and dementia. These observations open many previously unexplored avenues for developing novel therapeutics to treat these devastating diseases.
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Elshafei, Hesham. "Neurophysiological Mechanisms of Auditory Distractibility in the Healthy, Aging or Damaged Human Brain." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1255/document.
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Les mécanismes volontaires (V) et involontaires (I) de l’attention reposent sur les réseaux dorsal et ventral, convergeant dans le cortex préfrontal latéral (lPFC). La distractibilité accrue liée au vieillissement ou à une lésion frontale pourrait être due à une altération de l’équilibre entre ces mécanismes V et I, essentiel mais rarement étudié. Notre objectif est de tester, dans la modalité auditive, si (1) les oscillations alpha coordonnent l'activité du réseau dorsal, (2) les oscillations gamma celle du réseau ventral, (3) le couplage oscillatoire dans le lPFC maintient l’équilibre entre les deux réseaux. Ce travail vise également à étudier les corrélats oscillatoires de la distractibilité accrue liée au vieillissement ou à une atteinte frontale. Des données MEEG ont été enregistrées alors que des participants réalisaient le Competitive Attention Test, qui permet d’étudier simultanément les mécanismes V et I de l’attention. Nous avons montré que les oscillations alpha reflètent l’activation des mécanismes facilitateurs et suppresseurs de l’attention V, et la communication au sein du réseau dorsal ; alors que les oscillations gamma indexent l’activation du réseau ventral. De plus, le lPFC serait impliqué dans la communication au sein des deux réseaux, et le PFC médian dans l’équilibre attentionnel V/I. Nous avons également montré que la distractibilité accrue était liée à un déficit d’attention V au cours du vieillissement, et à une altération des processus V et I après lésion frontale. Ce travail de thèse offre donc une meilleure compréhension de la dynamique cérébrale oscillatoire sur laquelle repose l'équilibre attentionnel V/I, et donc la distractibilitéTop-down (TD) and bottom-up (BU) mechanisms of attention are supported by dorsal and ventral networks that mainly overlap in the lateral prefrontal cortex (lPFC). A balance between these mechanisms is essential, yet rarely investigated. Increased distractibility observed during ageing or after frontal damage could result from jeopardizing this balance. It has been proposed that distinct oscillatory frequencies support the activation of these two attention networks. Our main aim was to test, in the auditory modality, whether (1) alpha oscillations would coordinate activity within the dorsal TD network, (2) gamma activity would index the activation of the ventral BU network, (3) the lPFC would support the balance between these networks through oscillatory coupling. We also aimed to investigate the oscillatory correlates of the increased distractibility associated with ageing or frontal damage. MEEG data were recorded while participants performed the Competitive Attention Test, which enables simultaneous investigation of BU and TD attention mechanisms. We showed that alpha oscillations indexed facilitatory and suppressive mechanisms of TD attention, and communication within the dorsal network; while gamma oscillations indexed the ventral network activation. Moreover, the lPFC subtended communication in the two networks; with the TD/BU interaction occurring in the medial PFC. We also showed that ageing-related distractibility was of TD deficit origin. Finally, preliminary results suggest that lPFC damage can impact both TD and BU attention. This thesis provides novel insights into the brain oscillatory dynamics of the TD/BU attentional balance supporting distractibility
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BERLINGERI, MANUELA. "Brain dynamics associated with graceful and pathological aging: new morphometric and fMRI evidence." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2010. http://hdl.handle.net/10281/7816.
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In the last decade, graceful aging has often been associated with frontal hyperactivations in working- and episodic long-term memory tasks, a compensatory process, according to some, that allows the best normal olders to perform these tasks at a juvenile level, in spite of the natural cortical impoverishment.
It remains to be established, however, whether the frontal hyperactivation is the only possible neurofunctional manifestation of compensatory processes in halthy aging.
In this thesis I present a systematic investigation of this issue and related issues on pathological aging seen in MCI.
I first re-assessed the results of 23 recent neuroimaging papers on normal aging using a quantitative meta-analytic approach that allowed us to distinguish between task-dependent and task-independent age-related hyperactivations in healthy olders (Chapter 2). In particular, task-independent hyperactivations emerged in the prefrontal cortex (PFC) in line with the results commonly described in international litterature, while task-dependent hyperactivations emerged in brain regions beyond the prefrontal areas.
Further, we investigated more directly the existence of task-specific neurofunctional manifestations of compensatory processes in a new fMRI / VBM study (Chapter 3). In this study, 24 young and 24 healthy elderly participants were compared. Graceful aging was explored by investigating domains where most healthy olders perform like youngers (e.g. lexical-semantic knowledge) and tasks that are typically more challenging, like episodic long-term recognition memory tasks. With voxel-based morphometry we also studied to what extent changes of fMRI activation were consistent with the pattern of brain atrophy. We found that hyperactivations in the group of healthy olders were not restricted to the frontal lobes, rather they presented with task-dependent patterns. Moreover, only hypoactivations did systematically overlap with regional atrophy. On the basis of these results we suggest that compensatory processes associated with graceful aging are not necessarily a sign of early saturation of executive resources, if this saturation was to be represented by a systematic frontal hyperactivation.
The role of the PFC over-recruitment and age-related neurofunctional changes in healthy olders was further investigated in Chapter 4. In particular in this study we reviewed the neurofunctional data collected in the third Chapter in the light of the HAROLD model (Hemispheric Asymmetry Reduction in Olders). Again, the data clearly suggested that the manifestation of age-related neurofunctional changes of functional lateralization in healthy olders is not exclusively restricted to the frontal areas, rather these are distributed across the entire brain volume in a task-related manner.
Finally, in order to better address neurofunctional and neuroanatomical changes in pathological aging and to create a link with theoretical frameworks that describe graceful aging, we compared behavioural, neurofunctional and neuroanatomical data of 24 healthy olders and 9 aMCI patients, challenged with the same lexical-semantic and episodic long-term memory tasks used in Chapter 3. The between groups differences were analysed in the light of our previous findings on the neural pattern of compensatory processes in healthy aging (described in Chapter 3). A systematic pattern emerged: aMCI patients showed over-activations in parts of the task-specific neural networks that are dysfunctional in highly-performing healthy olders, while they under-recruited the task-specific compensatory neural networks typically over-activated by healthy older controls. Moreover, the over-recruitments of areas which became of no use in healthy aging showed a negative correlation with the gray matter density in the medial temporal lobe structures. These results are discussed in terms of lack of neural plasticity in pathological aging.
I conclude my dissertation with chapter 6 where I propose a neurocognitive account of healthy and pathological aging in terms of compensatory processes and neural plasticity.
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William, DuPont. "The Effects of Resistance Exercise Training on Cognition and Brain Function in Healthy Older Adult Women." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532087071781131.
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McDowell, Christine L. 1950. "Right hemisphere decline in the perception of emotion as a function of aging." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39771.
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Popplewell, Abigail M. "The effects of cognitive training on aging adults application of a rehabilitative categorization program /." Oxford, Ohio : Miami University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1145461078.
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Bennett, Ilana Jacqueline. "Aging, implicit sequence learning, and white matter integrity." Connect to Electronic Thesis (CONTENTdm), 2009. http://worldcat.org/oclc/463286305/viewonline.
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Mihai, Georgeta. "Methods for brain iron evaluation in normal aging T2 and phase measurements at 3 tesla and 7 tesla /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189791295.
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Rojic, Becker Divka Inge. "Effects of caloric restriction on brain aging and cognitive decline: Behavioral and biochemical analysis." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/663819.
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La restricción calórica (RC), definida como la reducción en la ingesta calórica sin causar desnutrición, ha demostrado ser una buena intervención para ralentizar el envejecimiento y aumentar la esperanza de vida. Sin embargo, los beneficios de la RC en los procesos cognitivos durante el envejecimiento han sido poco estudiados. Por esta razón, el principal objetivo de esta tesis fue determinar si el uso de la RC a lo largo de la vida puede ralentizar el deterioro cognitivo en el aprendizaje y en la memoria a corto y largo plazo, y además, modificar la expresión de diferentes parámetros moleculares en el cerebro durante el envejecimiento. Para lograrlo, se llevaron a cabo pruebas en ratas macho Wistar envejecidas (24-27 meses) alimentadas en condiciones de disminución del 30% de la ingesta desde el cuarto mes de edad, comparadas con ratas envejecidas (24-27 meses) y jóvenes (3-4 meses) alimentadas Ad libitum.
Tareas conductuales: Para analizar el aprendizaje y la memoria se utilizó el laberinto acuático de Morris (MWM), la discriminación simple de olores (ODT) y la memoria de reconocimiento de objetos en un laberinto de Y. Asimismo, para verificar si variables emocionales, motoras y olfativas podían haber afectado los resultados, se utilizó el campo abierto (OF), laberinto elevado (EPM) y el test de percepción olfativa.
Tareas bioquímicas: Se evaluó el estado general de salud de los animales a través de los niveles plasmáticos de triglicéridos, colesterol, fosfatasa alcalina (ALP), calcio, glucosa y hormonas como insulina, leptina, corticosterona y factor de crecimiento insulínico 1 (IGF-1). También, se cuantificaron los niveles de transmisión monoaminérgica mediante cromatografía liquida de alta eficacia (HPLC) y se analizó la transmisión glutamatérgica (niveles de receptores ionotrópicos NMDA y AMPA, tirosina hidroxilasa, triptófano hidroxilasa) y sinaptofisina, una proteína relacionada con la plasticidad sináptica, mediante Western Blot (WB).
Los principales resultados de esta tesis doctoral demostraron que la RC ralentiza el proceso de envejecimiento en la memoria a largo plazo con el MWM y en la memoria a corto plazo mediante la prueba de laberinto en Y. En contra, los resultados del ODT indicaron que los animales bajo RC no mejoraron los niveles de memoria a largo plazo en tareas reforzadas con comida, ya que esta puede aumentar la capacidad de respuesta a la recompensa y la motivación hacia el rendimiento en animales ya alimentariamente restringidos. Además, la RC mejoró los procesos bioquímicos subyacentes ya que revirtió la disminución de receptores AMPA y de monoaminas en el hipocampo, aunque no se presentaron diferencias entre los niveles de SYP o receptores NMDA, lo que indica que la RC no hizo efecto sobre estas proteínas. También se comprobó que la RC no afectó la locomoción ni causó mayor ansiedad que el propio proceso de envejecimiento analizado con OF y EPM. En general, los animales con RC presentaron un buen estado de salud, sin desnutrición, igual que el grupo control, tal y como indican los niveles de ALP y leptina. Por el contrario, no se encontraron cambios en los niveles de corticosterona, insulina, glucosa e IFG-1 entre los dos grupos de animales envejecidos cuyos niveles siguieron el patrón típico del envejecimiento.
En conclusión, la RC puede ser una buena intervención para desacelerar el declive cognitivo relacionado con la edad, aunque la intervención no fue efectiva en tareas con refuerzo alimentario. Además, la intervención dietética mejoró algunos de los parámetros bioquímicos o mantuvo niveles equiparables al proceso de envejecimiento en sí en otros.Caloric restriction (CR) is defined as the reduction of caloric intake, without causing malnutrition. This intervention has been shown to be capable of slowing down the progression of age-related diseases, as well as increasing animals’ lifespan. However, the potential benefits of CR for cognitive processes during aging have been scarcely studied. Therefore, the main objective of the present study was to determine whether administering a CR protocol through lifespan may counteract age-induced cognitive impairment seen in short-term and long-term memory tasks, as well as modify the expression of different molecular parameters in the brain. In order to achieve this objective, we evaluated the differences in memory task performance, as well as biochemical parameters, between three groups of animals: 1. Old male Wistar rats (24-27 months) on a 30% CR diet. 2. Old (24-27 months) rats fed Ad libitum. 3. Young control rats (3-4 months) also fed Ad libitum) Behavioral tasks: In order to test learning and memory, a Morris water maze (MWM), an odor discrimination task (ODT) and an object recognition memory task in a Y maze, were carried out. To evaluate whether emotional, motor or olfactory variables affected the outcome, an open field (OF), an elevated maze (EPM) and an olfactory perception test were administered. Biochemical tasks: In order to analyze the general health of the animals, blood plasma levels of triglycerides, cholesterol, alkaline phosphatase (ALP), calcium, glucose and hormones such as insulin, leptin, corticosterone and insulin-like growth factor 1 (IGF-1) were measured. In addition, in order to quantify changes in monoaminergic transmission, levels of dopamine, noradrenaline, serotonin and their metabolites were obtained from the hippocampus, striatum and frontal cortex, and analyzed using High Performance Liquid Chromatography (HPLC). Furthermore, in order to explore changes in glutamatergic transmission, levels of ionotropic NMDA and AMPA receptors, tyrosine hydroxylase, tryptophan hydroxylase and synaptophysin, a synaptic plasticity protein, were obtained from the same brain areas by Western Blot (WB). The main results of this doctoral thesis indicate that CR reduces the negative effects of aging on both short-term and long-term memory, as shown by the results obtained in the object recognition task in the Y maze and in the MWM, respectively. In contrast, the results of the ODT indicate that that CR animals’ performance did not improve in the long-term memory retention of an olfactory food-reinforced task, since abstaining can increase responsivity to food reward as well as the motivation to perform. Additionally, CR also enhanced the underlying biochemical processes, since it lessened the age-related diminution of AMPAr and monoaminergic levels in the HPC. However, no differences in SYP or NMDAr levels were found between groups, indicating that CR did not affect those proteins. Furthermore, results obtained in OF and EPM reveal that the nutritional intervention does not modify locomotion or anxiety levels any differently than the aging process itself. In general, CR animals were in good health with no signs of malnutrition, as demonstrated by them having the same levels of ALP and leptin in CR as their younger counterparts. Additionally, no differences in plasma levels of hormones, such as corticosterone, insulin, glucose and IFG-1 were found between Ad Libitum aged animals and the CR group, which presented typical old-age levels. In conclusion, CR can be considered to be an effective intervention to slow down age-related cognitive decline, as indicated in this doctoral thesis. However, the intervention is not effective in cognitive tasks that involve food reinforcement. In addition, said dietary intervention improved some of the biochemical parameters, or at least maintained expected levels for animals in their old-age.
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Ruiz, Rizzo Adriana Lucía [Verfasser], and Kathrin [Akademischer Betreuer] Finke. "Visual processing speed in the aging brain / Adriana Lucía Ruiz Rizzo ; Betreuer: Kathrin Finke." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1162443715/34.
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Bodily, Ty Alvin. "A Graph Theoretical Analysis of Functional Brain Networks Related to Memory and Healthy Aging." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7567.
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The cognitive decline associated with healthy aging begins in early adulthood and is important to understand as a precursor of and relative to mild cognitive impairment and Alzheimer disease. Anatomical atrophy, functional compensation, and network reorganization have been observed in populations of older adults. In the current study, we examine functional network correlates of memory performance on the Wechsler Memory Scale IV and the Mnemonic Discrimination Task (MST). We report a lack of association between global graph theory metrics and age or memory performance. In addition, we observed a positive association between lure discrimination scores from the MST and right hippocampus centrality. Upon further investigation, we confirmed that old subjects with poor memory performance had lower right hippocampus centrality scores than young subjects with high average memory performance. These novel results connect the role of the hippocampus in global brain network information flow to cognitive function and have implications for better characterizing and predicting memory decline in aging.
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Arkan, Ethar. "The Effect of Aging on the Blood Brain Barrier Permeability and Response to FluoxetineEnantiomers." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright150428514055809.
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Swan, Alicia. "Aging and the preclinical efficacy of nicotinamide in the treatment of traumatic brain injury /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1796420341&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Swan, Alicia Ann. "Aging and the Preclinical Efficacy of Nicotinamide in the Treatment of Traumatic Brain Injury." OpenSIUC, 2008. https://opensiuc.lib.siu.edu/theses/514.
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The clinical relevance of vitamin B3, nicotinamide (NAm), has been demonstrated in a variety of injury models to exert a number of therapeutic benefits in the protection against and treatment of traumatic brain injury (TBI). This study investigated its efficacy on recovery from TBI in animals of differing ages (6- and 10-months old) that were injured using the controlled cortical impact model and tested for motor and cognitive recovery following injury. Injured animals were treated with NAm or saline following injury and sham-injured animals were included as a control group. It was hypothesized that increasing age reduces the potentiality of recovery from injury as well as a decreased therapeutic benefit derived from the post-injury administration of NAm. The results found that neither the 6- nor 10-month old animals treated with NAm demonstrated improved functional recovery, indicating that age is an important factor in the vitamin's efficacy. These results indicate that the success of possible treatments for TBI needs to also consider the effects of an individual's age on the drug's effectiveness.
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Vannini, Patrizia. "Functional neurobiology in normal aging, mild cognitive impairment and Alzheimer's disease : focus on visuospatial processing using functional magnetic resonance imaging /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-164-7/.
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