Pre-stimulus EEG Microstates Correlate With Anticipatory Alpha Desynchronization.

Area of Science:

• Neuroscience
• Cognitive Electrophysiology

Background:

• Electrophysiological markers are crucial for understanding event anticipation.
• Pre-stimulus microstate topography offers insights into anticipatory brain activity.
• The relationship between microstate metrics and alpha power reduction was previously unclear.

Purpose of the Study:

• To investigate the correlation between pre-stimulus microstate features (GEV, FOO) and alpha power reduction (ERD).
• To determine if microstate metrics can serve as electrophysiological correlates of cortical activation during anticipation.

Main Methods:

• Extraction of microstates during a semantic memory task's expectancy period.
• Analysis of correlations between microstate metrics (GEV, FOO) and alpha power reduction (ERD) indices.
• Focus on dominant and non-dominant microstate occurrences.

Main Results:

• A positive correlation was found between the occurrence of the dominant microstate and both the mean amplitude and peak magnitude of high-alpha ERD.
• Higher frequency of occurrence (FOO) of the dominant microstate correlated with stronger alpha power decrease.
• The dominant microstate's FOO also correlated positively with the latency of the alpha ERD peak.
• No significant correlations were found between Global Explained Variance (GEV) and alpha ERD indices.

Conclusions:

• The occurrence of the dominant microstate is a potential electrophysiological correlate of cortical activation.
• Only the dominant microstate's occurrence, not GEV, is a useful index for anticipatory brain activity.
• These findings refine the understanding of electrophysiological markers in cognitive anticipation.