Evidence for an anterior-posterior gradient of age-related volume reduction along the hippocampal longitudinal axis has been reported in normal aging, but functional changes have yet to be systematically investigated. The current study applied an advanced brain mapping technique, large deformation diffeomorphic metric mapping (LDDMM), automatically delineating the hippocampus into the anterior and posterior segments based on anatomical landmarks. We studied this anterior-posterior gradient in terms of structural and functional MRI in 66 participants aged from 19 to 79 years. The results showed age-related structural volume reduction in both anterior and posterior hippocampi, with greater tendency for anterior decrease. FMRI task contrasts that robustly activated the anterior (associative/relational processing) and posterior (novelty) hippocampus independently, showed only significant reduction of activation in the anterior hippocampus as age increased. Our results revealed positive correlation between structural atrophy and functional decrease in the anterior hippocampi, regardless of task performance in normal aging. These findings suggest that anatomy and functions related to the anterior hippocampus may be more vulnerable to aging, than previously thought.
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http://dx.doi.org/10.1002/hbm.21364 | DOI Listing |
Neurobiol Sleep Circadian Rhythms
May 2025
INCIA, EPHE, Université PSL, Univ Bordeaux, CNRS, 146, Rue Léo Saignat, 33076, Bordeaux, France.
To better understand the relationship between the rest-activity rhythms and cognitive impairments during aging, we assessed the longitudinal changes in the rest-activity rhythms in an elderly population and their possible detrimental effect on the hippocampal network. This was done longitudinally in a rural cohort with two actigraphic assessments and brain imaging examinations, seven years apart. A segmentation of the hippocampus and its related structures was used to assess volumes and functional connectivity in this network based on anatomical and resting state functional data.
View Article and Find Full Text PDFFree Neuropathol
January 2024
Department of Pathology, Nash Family Department of Neuroscience, Department of Artificial Intelligence & Human Health, Neuropathology Brain Bank & Research CoRE, Ronald M. Loeb Center for Alzheimer's Disease, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
This review highlights a collection of both diverse and highly impactful studies published in the previous year selected by the author from the neurodegenerative neuropathology literature. As with previous reviews in this series, the focus is, to the best of my ability, to highlight human tissue-based experimentation most relevant to experimental and clinical neuropathologists. A concerted effort was made to balance the selected studies across neurodegenerative disease categories, approaches, and methodologies to capture the breadth of the research landscape.
View Article and Find Full Text PDFEur J Med Res
January 2025
Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74 Zhongshan Road 2, Guangzhou, 510080, Guangdong, China.
Background: Dementia is a growing public health concern with limited effective treatments. Diet may be a modifiable factor that significantly impacts brain health. Mediterranean diet (MeDi) has been suggested to be associated with brain Magnetic Resonance Imaging (MRI) markers related to dementia, but the existing evidence is inconsistent.
View Article and Find Full Text PDFBrain
January 2025
U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Neuropresage Team; INSERM, University of Caen Normandy; GIP Cyceron, 14000 Caen, France.
Curing Alzheimer's disease remains hampered by an incomplete understanding of its pathophysiology and progression. Exploring dysfunction in medial temporal lobe networks, particularly the anterior-temporal (AT) and posterior-medial (PM) systems, may provide key insights, as these networks exhibit functional connectivity alterations along the entire Alzheimer's continuum, potentially influencing disease propagation. However, the specific changes in each network and their clinical relevance across stages are not yet fully understood.
View Article and Find Full Text PDFJ Neurol
January 2025
Department of Central laboratory, Xuanwu Hospital of Capital Medical University, Beijing, 100053, P.R. China.
Background: Circadian disruptions are increasingly recognized in Alzheimer's disease (AD) patients and may influence disease onset and progression. This study examines how AD pathology affects blood-borne factors that regulate circadian rhythms.
Methods: Eighty-five participants from the Sino Longitudinal Study on Cognitive Decline were enrolled: 35 amyloid-beta negative normal controls (Aβ- NCs), 23 amyloid-beta positive normal controls (Aβ+ NCs), 15 patients with amnestic mild cognitive impairment (aMCI), and 12 with Alzheimer's disease dementia (ADD).
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