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Dynamics of large-scale brain activity in health and disease

Bibliographic Details
Main Author: Montez, Maria Teresa Andrade Santos Costa, 1979-
Publication Date: 2008
Language: eng
Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
Download full: http://hdl.handle.net/10451/1571
Summary: Tese de doutoramento em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2008
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spelling Dynamics of large-scale brain activity in health and diseaseDoença de AlzheimerElectroencefalografiaMagnetoencefalografiaEngenharia biomédicaTeses de doutoramento - 2008Tese de doutoramento em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2008Cognition relies on the integration of information processed in widely distributed brain regions. Neuronal oscillations are thought to play an important role in the supporting local and global coordination of neuronal activity. This study aimed at investigating the dynamics of the ongoing healthy brain activity and early changes observed in patients with Alzheimer's disease (AD). Electro- and magnetoencephalography (EEG/MEG) were used due to high temporal resolution of these techniques. In order to evaluate the functional connectivity in AD, a novel algorithm based on the concept of generalized synchronization was improved by defining the embedding parameters as a function of the frequency content of interest. The time-frequency synchronization likelihood (TF SL) revealed a loss of fronto-temporal/parietal interactions in the lower alpha (8 10 Hz) oscillations measured by MEG that was not found with classical coherence. Further, long-range temporal (auto-) correlations (LRTC) in ongoing oscillations were assessed with detrended fluctuation analysis (DFA) on times scales from 1 25 seconds. Significant auto-correlations indicate a dependence of the underlying dynamical processes at certain time scales of separation, which may be viewed as a form of "physiological memory". We tested whether the DFA index could be related to the decline in cognitive memory in AD. Indeed, a significant decrease in the DFA exponents was observed in the alpha band (6 13 Hz) over temporo-parietal regions in the patients compared with the age-matched healthy control subjects. Finally, the mean level of SL of EEG signals was found to be significantly decreased in the AD patients in the beta (13 30 Hz) and in the upper alpha (10 13 Hz) and the DFA exponents computed as a measure of the temporal structure of SL time series were larger for the patients than for subjects with subjective memory complaint. The results obtained indicate that the study of spatio-temporal dynamics of resting-state EEG/MEG brain activity provides valuable information about the AD pathophysiology, which potentially could be developed into clinically useful indices for assessing progression of AD or response to medication.Hansen, Klaus Linkenkaer-Soares, Eduardo Ducla, 1944-Repositório da Universidade de LisboaMontez, Maria Teresa Andrade Santos Costa, 1979-2010-07-27T08:59:35Z20082008-01-01T00:00:00Zdoctoral thesisinfo:eu-repo/semantics/publishedVersionapplication/pdfapplication/pdftext/xmlhttp://hdl.handle.net/10451/1571enginfo:eu-repo/semantics/openAccessreponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiainstacron:RCAAP2025-03-17T12:39:35Zoai:repositorio.ulisboa.pt:10451/1571Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireinfo@rcaap.ptopendoar:https://opendoar.ac.uk/repository/71602025-05-29T02:25:05.829727Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologiafalse
dc.title.none.fl_str_mv Dynamics of large-scale brain activity in health and disease
title Dynamics of large-scale brain activity in health and disease
spellingShingle Dynamics of large-scale brain activity in health and disease
Montez, Maria Teresa Andrade Santos Costa, 1979-
Doença de Alzheimer
Electroencefalografia
Magnetoencefalografia
Engenharia biomédica
Teses de doutoramento - 2008
title_short Dynamics of large-scale brain activity in health and disease
title_full Dynamics of large-scale brain activity in health and disease
title_fullStr Dynamics of large-scale brain activity in health and disease
title_full_unstemmed Dynamics of large-scale brain activity in health and disease
title_sort Dynamics of large-scale brain activity in health and disease
author Montez, Maria Teresa Andrade Santos Costa, 1979-
author_facet Montez, Maria Teresa Andrade Santos Costa, 1979-
author_role author
dc.contributor.none.fl_str_mv Hansen, Klaus Linkenkaer-
Soares, Eduardo Ducla, 1944-
Repositório da Universidade de Lisboa
dc.contributor.author.fl_str_mv Montez, Maria Teresa Andrade Santos Costa, 1979-
dc.subject.por.fl_str_mv Doença de Alzheimer
Electroencefalografia
Magnetoencefalografia
Engenharia biomédica
Teses de doutoramento - 2008
topic Doença de Alzheimer
Electroencefalografia
Magnetoencefalografia
Engenharia biomédica
Teses de doutoramento - 2008
description Tese de doutoramento em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2008
publishDate 2008
dc.date.none.fl_str_mv 2008
2008-01-01T00:00:00Z
2010-07-27T08:59:35Z
dc.type.driver.fl_str_mv doctoral thesis
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10451/1571
url http://hdl.handle.net/10451/1571
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
text/xml
dc.source.none.fl_str_mv reponame:Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
instname:FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron:RCAAP
instname_str FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
instacron_str RCAAP
institution RCAAP
reponame_str Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
collection Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
repository.name.fl_str_mv Repositórios Científicos de Acesso Aberto de Portugal (RCAAP) - FCCN, serviços digitais da FCT – Fundação para a Ciência e a Tecnologia
repository.mail.fl_str_mv info@rcaap.pt
_version_ 1833601345945337856

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