Load-dependent alpha suppression is related to working memory capacity for numbers.

Area of Science:

• Cognitive Neuroscience
• Neuroimaging

Background:

• Alpha suppression is theorized to enhance stimulus processing in working memory by increasing cortical excitability.
• The relationship between alpha suppression and working memory performance shows inconsistent evidence, hindering its use as a cognitive biomarker.

Purpose of the Study:

• To investigate the link between individual differences in alpha suppression and working memory capacity.
• To determine if alpha suppression can serve as a brain-based measure of working memory functioning.

Main Methods:

• Electroencephalography (EEG) was used to record brain activity in participants performing arithmetic tasks with varying working memory loads (low vs. high).
• Participants calculated either the product (low-load) or the difference of products (high-load) of digits.

Main Results:

• Alpha suppression was observed in parietal regions and intensified with increased working memory load in about 80% of participants.
• Greater alpha suppression during increased cognitive load was associated with larger declines in behavioral performance and lower Digit Span scores.
• Individuals with poorer working memory capacity exhibited more prominent alpha suppression.

Conclusions:

• Alpha suppression, particularly its interindividual variability in sensitivity, may function as a reliable brain-based indicator of working memory capacity.
• This finding supports the use of EEG-based alpha activity measures for evaluating cognitive processes like working memory.