Cardiorespiratory effects on default-mode network activity as measured with fMRI

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Functional Magnetic Resonance Imaging (fMRI)

Background:

• The default-mode network (DMN) shows higher activation during rest than during tasks.
• BOLD signal changes in the DMN are debated: cognitive processing vs. cardiorespiratory (CR) effects.
• CR effects can influence BOLD signal measurements independently of neural activity.

Purpose of the Study:

• To investigate if CR effects alone explain BOLD signal changes in the DMN.
• To differentiate between neural and CR origins of DMN activity.
• To assess the impact of cognitive task demands on DMN activity after CR correction.

Main Methods:

• Simultaneous measurement of brain activity, heart rate, and respiration.
• Application of RETROICOR and additive linear modeling to correct for CR effects.
• Comparison of DMN activity during resting-state and cognitive tasks (high- and low-demand).

Main Results:

• CR effects were detected within the DMN's frequency range and spatial locations.
• DMN deactivation and resting-state connectivity remained significant after CR correction.
• Task-demand modulation of DMN deactivation persisted post-correction, while task-related activation was removed by CR correction.

Conclusions:

• BOLD signal changes in the DMN are not solely attributable to CR effects.
• Evidence supports a role for cognitive neuronal processing in DMN activity.
• CR correction methods are crucial for accurately interpreting DMN BOLD signals.