Residual coherence and residual envelope correlation in MEG/EEG source-space connectivity analysis

Area of Science:

• Neuroscience
• Biophysics
• Signal Processing

Background:

• Source-space coherence analysis is widely used for functional connectivity estimation with MEG/EEG.
• Leakage properties of inverse algorithms introduce spurious coherence, creating a 'seed blur' artifact that hinders interpretation.
• This artifact obscures crucial details of brain interactions.

Purpose of the Study:

• To introduce a novel method, residual coherence, to eliminate spurious coherence caused by imaging algorithm leakage.
• To theoretically demonstrate the equivalence of residual coherence with corrected imaginary coherence.
• To extend residual coherence to residual envelope correlation for high-frequency brain activity analysis.

Main Methods:

• Development of the residual coherence method to correct for leakage artifacts.
• Theoretical analysis to establish the equivalence between residual coherence and corrected imaginary coherence.
• Extension of residual coherence to residual envelope correlation for high-frequency data.

Main Results:

• The proposed residual coherence method effectively removes spurious coherence artifacts.
• Theoretical analysis confirmed the equivalence between residual coherence and corrected imaginary coherence.
• Residual envelope correlation proved effective for connectivity estimation in high-frequency brain activity.

Conclusions:

• Residual coherence is a robust method for accurate functional connectivity estimation from MEG/EEG data.
• The novel residual coherence and residual envelope correlation methods overcome limitations of traditional coherence analysis.
• These methods enhance the reliability of brain connectivity studies by mitigating leakage-induced artifacts.