Harmonizing brain rhythms: cortex-wide neuronal dynamics underpin quasi-periodic patterns in resting-state fMRI.

Area of Science:

• Neuroscience
• Systems Neuroscience
• Neuroimaging

Background:

• Functional magnetic resonance imaging (fMRI) detects whole-brain activity, including resting-state patterns like quasi-periodic patterns (QPPs).
• These fMRI-QPPs exhibit consistent spatiotemporal dynamics, are conserved across species, and are altered in neurological diseases.
• The precise neural origins of blood-oxygen-level dependent (BOLD) fMRI signals, particularly QPPs, remain incompletely understood due to the indirect nature of the BOLD signal.

Purpose of the Study:

• To investigate the neural underpinnings of fMRI-QPPs using simultaneous wide-field calcium (WF-Ca ²⁺ ) imaging and fMRI.
• To establish a direct link between neural activity patterns and BOLD-fMRI QPPs.

Main Methods:

• Simultaneous recording of cortex-wide neural activity using WF-Ca ²⁺ imaging and whole-brain fMRI in animal models.
• Application of QPP analysis to both WF-Ca ²⁺ and fMRI data streams.
• Comparative analysis to identify spatiotemporal correlations between neural activity waves and BOLD signal patterns.

Main Results:

• A robust, time-locked correlation was identified between QPPs detected via WF-Ca ²⁺ imaging and fMRI-QPPs.
• These findings demonstrate that BOLD fMRI QPPs are a direct reflection of preceding, slower waves of neural activity.
• The spatial and temporal precision of this relationship was confirmed.

Conclusions:

• BOLD fMRI QPPs have a direct neural origin in slow waves of neural activity.
• This study validates the hypothesis that fMRI-QPPs accurately represent underlying neural dynamics.
• The multimodal approach provides a powerful tool for understanding the neural basis of brain activity patterns detected by fMRI.