Segregated precuneus network and default mode network in naturalistic imaging.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• A precuneus network (PCUN), or "parietal memory network", is proposed, overlapping spatially with the default mode network (DMN).
• Distinguishing PCUN and DMN is crucial for understanding brain function and disorders, but consensus and biological evidence are lacking.
• Previous resting-state studies suggest separation, yet direct functional evidence is needed.

Purpose of the Study:

• To compare the responses and functional couplings of PCUN and DMN during movie watching.
• To investigate how movie context continuity modulates the activity of these two brain networks.
• To provide biological evidence supporting the distinct roles of PCUN and DMN.

Main Methods:

• Identified PCUN and DMN using resting-state fMRI in 48 healthy participants.
• Analyzed network responses to a context-rich video versus a context-shuffled version using temporal fluctuation variance and functional connectivity.
• Examined functional network connectivity with primary visual regions.

Main Results:

• Contextual scrambling affected DMN and PCUN fluctuation levels in opposite ways.
• PCUN's internal functional connectivity (FC) was more sensitive to contextual continuity than DMN's.
• PCUN demonstrated significantly stronger functional network connectivity with visual regions compared to DMN.

Conclusions:

• Findings support distinct functional roles for PCUN and DMN in processing context-rich information.
• The results advocate for considering PCUN and DMN separately in resting-state research and clinical studies.
• This study provides biological evidence for differentiating PCUN and DMN based on their responses to dynamic, contextual stimuli.