Predicting Stimulus Modality and Working Memory Load During Visual- and Audiovisual-Acquired Equivalence Learning

Area of Science:

• Cognitive Neuroscience
• Neuroimaging

Background:

• Extensive research exists on electroencephalography (EEG) correlates of associative working memory (WM) load.
• The influence of stimulus modality on EEG patterns during WM processes remains less understood.

Purpose of the Study:

• To investigate the effect of stimulus modality (visual vs. audiovisual) on EEG patterns during associative working memory.
• To re-analyze existing EEG data to identify predictive markers for WM load and modality.

Main Methods:

• Re-analysis of EEG datasets from visual and audiovisual equivalence learning tasks.
• Utilized a staircase method to manipulate working memory load.
• Employed support vector machine algorithms to predict WM load and stimulus modality using power spectral density, phase connectivity, and cross-frequency coupling (CFC).

Main Results:

• High accuracy (>90%) in predicting stimulus modality using power spectral density and theta-beta cross-frequency coupling (CFC).
• Predicting working memory load (≥75% accuracy) was more successful than predicting stimulus modality using theta and alpha phase connectivity.
• Low working memory load showed maximal frontal and parieto-occipital connectivity in theta and alpha bands.

Conclusions:

• Findings validate previous studies dissociating stimulus modality using power spectra and CFC.
• Emphasizes the crucial role of theta and alpha frontoparietal connectivity in working memory load.
• EEG analysis offers insights into modality-specific and load-dependent neural mechanisms in working memory.