Abstract
Brain aging is a complex and heterogeneous process characterized by the selective loss and preservation of brain functions. This study examines the normal aging effects on the cerebral cortex by characterizing changes in functional connectivity using resting-state fMRI data. Previous resting-state fMRI studies on normal aging have examined specific networks of the brain, whereas few studies have examined cortical-cortical connectivities across the entire brain. To characterize the effects of normal aging on the cerebral cortex, we proposed the Pearson functional product-moment correlation coefficient for measuring functional connectivity, which has advantages over the traditional correlation coefficient. The distinct patterns of changes in functional connectivity within and among the four cerebral lobes clarified the effects of normal aging on cortical function. Besides, the advantages of the proposed approach over other methods considered were demonstrated through simulation comparisons. The results showed heterogeneous changes in functional connectivity in normal aging. Specifically, the elderly group exhibited enhanced inter-lobe connectivity between the frontal lobe and the other lobes. Inter-lobe connectivity decreased between the temporal and parietal lobes. The results support the frontal aging hypothesis proposed in behavioral and structural MRI studies. In conclusion, functional correlation analysis enables differentiation of changes in functional connectivities and characterizes the heterogeneous aging effects in different cortical regions.
Highlights
The blood-oxygenation-level-dependent (BOLD) signal measured through fMRI reflects hemodynamic changes resulting from local neural activity [1, 2]
To investigate the normal aging effect on functional connectivity, we evaluate the statistical significance of the paired PFCorr differences between the young and the elderly groups by testing the hypotheses below
This is the first report on the effects of aging on cortical-cortical functional connectivity
Summary
The blood-oxygenation-level-dependent (BOLD) signal measured through fMRI reflects hemodynamic changes resulting from local neural activity [1, 2]. Resting-state fMRI data analysis involves evaluating coherent activity among brain regions and characterizing the functional connectivity of brain networks [9, 10]. The set of simultaneously recorded region-specific BOLD signal profiles of subjects intrinsically formed a set of multivariate functional data sampled from a set of multivariate random functions. We used the FDA methods to characterize aging-related changes in resting-state brain activity by calculating cortical-cortical connectivities across the whole brain, instead of focusing on specific networks. Such approach was never reported in the rsfMRI literature. We performed the simulations to compare the proposed method with other methods of measuring functional connectivity.We examined whether the proposed method distinguishes the effects of aging in large-scale cortical-cortical connectivities across the whole brain
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
