EEG phase synchrony differences across visual perception conditions may depend on recording and analysis methods.

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Brain Activity

Background:

• The neural synchrony hypothesis suggests that synchronized neural activity underlies conscious perception.
• Previous studies indicated greater neural synchrony for upright faces compared to inverted faces.

Purpose of the Study:

• To replicate findings on neural synchrony for upright vs. inverted Mooney faces.
• To investigate if inverted stimuli evoke neural synchrony by comparing them to scrambled stimuli.
• To examine the influence of data analysis parameters on observed synchrony differences.

Main Methods:

• Multichannel electroencephalography (EEG) recorded gamma-range spectral power and inter-electrode phase synchrony.
• Wavelet-based methods were used to analyze data from upright, inverted, and scrambled Mooney face stimuli.
• Analysis involved varying frequency selection criteria and EEG reference derivations.

Main Results:

• Initial analysis, using frequency selection from upright stimuli, showed greater phase synchrony for upright faces.
• However, substantial synchrony was observed across all conditions (upright, inverted, scrambled).
• Differences in phase synchrony disappeared when analysis parameters (frequency selection, reference derivation) were optimized, revealing robust synchrony for non-face stimuli as well.

Conclusions:

• Observed differences in neural synchrony between face and non-face perception are dependent on the chosen analytical parameters.
• Neural synchrony is not exclusive to face perception but is also present during the perception of non-face stimuli.
• Careful selection of frequency and reference is crucial for accurate interpretation of neural synchrony studies.