Default Mode Network (DMN) Activity Evaluation

Introduction to DMN Evaluation Methods

The American Academy of Neurology recommends using resting-state functional magnetic resonance imaging (fMRI) as the primary method to evaluate Default Mode Network (DMN) activity, measuring spontaneous fluctuations of the BOLD signal when the brain is "at rest" 1, 2
The European College of Neuropsychopharmacology suggests that electroencephalography (EEG) can be used to evaluate oscillatory dynamics, with particular attention to frequency bands that reflect DMN activity 3

Independent component analysis (ICA) is a network-based method used to identify temporally coherent functional networks, utilized to examine connectivity within the DMN 1, 2
Seed-based approaches analyze functional connectivity between one or more predefined regions of interest (ROI), such as the anterior cingulate cortex 1, 4
Graph theory is a method used to characterize global and regional properties of functional brain networks, including the DMN 2, 4
Amplitude of low-frequency fluctuations (ALFF) quantifies the amplitude of the BOLD signal power spectrum, reflecting neural activity 2, 4

Increased functional connectivity between DMN regions, particularly in the posterior part (posterior cingulate cortex), may indicate hyperactivity 1, 2
Reduced functional connectivity between DMN regions, especially in the anterior part (medial prefrontal cortex), may indicate hypoactivity 1, 2
Decreased ALFF in the dorsal anterior cingulate cortex and DMN regions may indicate hypoactivity 2, 4
Reduced "small worldness" and "degree" in the cingulate cortex for the DMN may indicate altered network properties 2, 4

The American College of Neuropsychopharmacology notes that methodological variability in resting-state studies can lead to inconsistent results 1, 2
It is essential to consider both anterior and posterior DMN connectivity, as they may show opposing alterations 1, 2