Related Experiment Video
Updated: Jun 5, 2026
08:43
Application of Granger Causality Analysis of the Directed Functional Connection in Alzheimer's Disease and Mild Cognitive Impairment
Published on: August 7, 2017
Default mode network connectivity in stable vs progressive mild cognitive impairment.
J R Petrella1, F C Sheldon, S E Prince
1Department of Radiology and Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC, USA. jeffrey.petrella@duke.edu
Neurology
|January 14, 2011
Summary
Default mode network (DMN) dysfunction in Alzheimer disease (AD) and mild cognitive impairment (MCI) can predict cognitive decline. Functional MRI (fMRI) connectivity indices effectively distinguish MCI patients who progress to AD from those who remain stable.
Area of Science:
- Neuroimaging
- Cognitive Neuroscience
- Neurology
Background:
- Default mode network (DMN) dysfunction is observed in Alzheimer disease (AD) and mild cognitive impairment (MCI).
- Previous studies used cross-sectional fMRI, but predictive utility for cognitive decline remains unexplored.
Purpose of the Study:
- To investigate the predictive value of DMN connectivity for future cognitive decline in individuals with MCI.
- To assess if fMRI-derived DMN indices can differentiate MCI patients who progress to AD from those who remain stable.
Main Methods:
- fMRI scans were acquired during a face-name memory task from 68 subjects (25 controls, 31 MCI, 12 AD).
- MCI subjects were followed for 2.4 years to track progression to AD.
- Goodness-of-fit (GOF) indices of DMN expression were calculated and correlated with cognitive decline and functional status.
Main Results:
- DMN connectivity (GOF indices) was significantly lower in MCI and AD compared to controls (p < 0.0001).
- Baseline GOF indices predicted progression from MCI to dementia, independent of other clinical factors.
- In MCI, lower GOF indices correlated with greater decline in functional status (r = -0.40, p < 0.04).
Conclusions:
- fMRI-based DMN connectivity indices can predict cognitive decline and conversion to AD in MCI patients over 2-3 years.
- Findings suggest distinct functional brain connectivity endophenotypes in MCI, correlating with memory scores and progression rates.
Related Concept Videos
01:30Cognitive Development During Adulthood
Cognitive development continues throughout adulthood, undergoing significant shifts across early, middle, and late stages. Individual transition occurs from adolescent idealism to pragmatic and adaptable thinking in early adulthood. During this period, individuals learn to integrate personal beliefs with the recognition that other perspectives are equally valid. Exposure to the complexities of modern society, diverse experiences, and higher education contribute to this adaptive thought process,...
01:22Dementia l: Introduction
Dementia is an acquired, progressive syndrome characterized by a decline in multiple cognitive domains severe enough to impair daily functioning and reduce independence. Although memory loss is a central feature, the diagnosis requires additional deficits involving language, executive function, visuospatial skills, judgment, calculation, or abstract reasoning. These cognitive impairments reflect underlying neurodegenerative or vascular processes that gradually disrupt neuronal networks...
01:29Alzheimer Disease l: Introduction
Alzheimer disease is a chronic, progressive, and irreversible neurodegenerative disorder and the most common cause of dementia in older adults. It leads to gradual neuronal loss, causing cognitive decline, behavioral changes, and loss of functional independence.Risk Factors and EtiologyThe disease is multifactorial. Age is the strongest risk factor, with prevalence doubling every 5 years after age 65. Genetic factors include mutations in genes such as APP, PSEN1, and PSEN2, which are associated...
01:26Alzheimer's Disease: Overview
Alzheimer's Disease (AD) is a continually advancing neurodegenerative disorder, distinguished by escalating memory loss, cognitive dysfunction, and dementia. The disease unfolds in three stages: preclinical, mild cognitive impairment (MCI), and dementia. Its onset is insidious, and the progression gradual, with the cause not well explained by other disorders.
The clinical diagnosis of AD hinges on the presence of memory and other cognitive impairments. Biomarkers, such as changes in Aβ and tau...
The clinical diagnosis of AD hinges on the presence of memory and other cognitive impairments. Biomarkers, such as changes in Aβ and tau...
01:23Alzheimer Disease ll: Pathophysiology
Alzheimer disease involves structural changes in the brain that begin long before symptoms appear. The most distinctive features are extracellular neuritic plaques and intracellular neurofibrillary tangles.Neuritic plaques form in the cerebral cortex and around blood vessels. These plaques contain a dense core of beta-amyloid (Aβ)—a toxic protein fragment that clumps outside neurons. The core is surrounded by damaged neuronal extensions, as well as reactive astrocytes and microglia. Abnormal...
01:19High-Level and Low-Level Awareness
Controlled processes in human consciousness represent high-alert mental states where individuals deliberately focus their attention on achieving specific goals. Controlled processes can be seen in situations like mastering new technology, where a person might become so absorbed that they ignore surrounding distractions. Such processes involve selective attention, requiring one to concentrate on particular elements of experience while disregarding others. These are governed by executive...