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Updated: Jun 23, 2026
12:09
Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy
Published on: August 5, 2014
Functional network contributions to longitudinal tau spread in Posterior Cortical Atrophy.
Yuta Katsumi1, Ryan Eckbo1, Scott M McGinnis1,2
1Frontotemporal Disorders Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA USA.
NPJ Dementia
|June 22, 2026
Summary
Longitudinal tau spreading in posterior cortical atrophy (PCA) begins in visual and attention networks, then spreads to other brain regions like the default mode network (DMN). This progression highlights key pathways in Alzheimer's disease.
Area of Science:
- Neuroscience
- Neurology
- Radiology
Background:
- Posterior cortical atrophy (PCA) involves progressive visual-cognitive deficits.
- Alzheimer's disease-related tau pathology in posterior cortical areas underlies PCA.
- Understanding tau spreading patterns is crucial for early diagnosis and treatment.
Purpose of the Study:
- To investigate longitudinal tau spreading patterns in early-stage PCA.
- To identify primary tau epicenters and their influence on subsequent tau accumulation.
- To explore the role of specific brain networks in tau propagation.
Main Methods:
- Structural MRI and 18F-Flortaucipir PET scans were performed at baseline and follow-up in 23 PCA patients.
- Directional regression analysis was used to model temporal directionality of tau spread.
- Seed-based analysis and graph theory quantified tau epicenters and network involvement.
Main Results:
- Tau epicenters were identified in the visual and dorsal attention networks (DAN).
- Tau spread directionally from posterior cortical areas to anterior DAN nodes and the default mode network (DMN).
- The visual network and posterior DMN were identified as hubs for tau spread.
Conclusions:
- Longitudinal tau spread in PCA follows a hierarchical progression.
- Initial tau deposition in visual and DAN networks predicts spread to other regions, including the DMN.
- Dynamic connectivity reorganization may mediate tau spread as pathology saturates primary networks.
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