Related Experiment Video
Updated: Jun 2, 2025
Network Analysis of the Default Mode Network Using Functional Connectivity MRI in Temporal Lobe Epilepsy
Published on: August 5, 2014
Lateralization of the Aberrant Amplitude of Low-Frequency Fluctuation within the Default Mode Network in Patients
Yongjia Shao1, Yan Li2, Zijian Wang3
1Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, No. 150 Jimo Road, Pudong New Area, Shanghai 200120, China (Y.S., Y.Y., Y.W., G.Z.).
Rationale And Objectives:
Alzheimer's disease (AD) is the most common pathogenesis of dementia, and mild cognitive impairment (MCI) is considered as the intermediate stage from normal elderly to AD. Early detection of MCI is an essential step for the timely intervention of AD to slow the progression of this disease. Different form previous studies in the whole-brain spontaneous activities, this research aimed to explore the low-frequency amplitude spectrum activities of patients with MCI within the default mode network (DMN), which has been involved in the process of maintaining normal cognitive function.
Materials And Methods:
Based on resting-state functional magnetic resonance imaging, the amplitude of low-frequency fluctuation (ALFF) was used to analyze alterations in brain regions. The Mini-Mental State Examination and Montreal Cognitive Assessment were used for cognitive assessments. The correlation between imaging and behavioral results was analyzed among patients with MCI (n=36) and normal controls (n=26).
Results:
The DMN is the highest coverage of brain network regarding changes in local brain activity in patients with MCI. And the MCI group showed significant aberrant lateralization of the ALFF value.
Conclusion:
The current results of our study has confirmed the hypothesis of cerebral functional impairment and compensation, and suggests that functional changes in the brain regions with reduced values of the ALFF occurred earlier than those with increased values. In a word, it suggested that the aberrant spontaneous brain activity in the DMN might be a specific imaging marker for improving MCI diagnoses.
Insights
Early detection of mild cognitive impairment (MCI) is crucial for Alzheimer's disease (AD) intervention. This study found aberrant spontaneous brain activity in the default mode network (DMN) in MCI patients, suggesting it as a potential imaging biomarker.
Area of Science:
- Neuroscience
- Medical Imaging
- Cognitive Science
Background:
- Alzheimer's disease (AD) is a leading cause of dementia, with mild cognitive impairment (MCI) as its precursor.
- Early identification of MCI is vital for timely AD intervention and slowing disease progression.
Purpose of the Study:
- To investigate low-frequency amplitude spectrum activities within the default mode network (DMN) in individuals with MCI.
- To explore the potential of DMN activity as an imaging biomarker for MCI detection.
Main Methods:
- Resting-state functional magnetic resonance imaging (fMRI) was employed.
- Amplitude of Low-Frequency Fluctuation (ALFF) analysis was performed to assess brain activity.
- Cognitive function was evaluated using the Mini-Mental State Examination and Montreal Cognitive Assessment.
Main Results:
- The default mode network (DMN) exhibited the most significant changes in local brain activity in MCI patients.
- The MCI group demonstrated significant aberrant lateralization of ALFF values within the DMN.
Conclusions:
- Findings support the hypothesis of cerebral functional impairment and compensation in MCI.
- Aberrant spontaneous brain activity in the DMN may serve as a specific imaging marker for enhancing MCI diagnoses.
- Functional brain changes with reduced ALFF values appear earlier than those with increased values in MCI.
