Neural measures of working memory in a bilateral change detection task

Area of Science:

• Cognitive Neuroscience
• Neuroscience
• Psychology

Background:

• Change detection tasks are crucial for studying visual working memory.
• Negative slow wave (NSW) and contralateral delay activity (CDA) are EEG measures of working memory load.
• Current methods for measuring NSW and CDA have limitations.

Purpose of the Study:

• To develop a novel change detection task enabling simultaneous measurement of NSW and CDA.
• To investigate how NSW and CDA reflect different aspects of working memory load (set size and net load).
• To assess the predictive power of NSW, CDA, and decoding accuracy for working memory capacity.

Main Methods:

• A novel bilateral change detection task was designed with varying hemifield distributions to create 'net load'.
• Electroencephalography (EEG) was used to record NSW and CDA.
• Multivariate linear classification was employed to decode set size and net load from EEG signals.

Main Results:

• NSW positively correlated with set size, while CDA increased with net load.
• EEG decoding successfully predicted set size and net load.
• Both NSW, CDA, and decoding accuracy predicted individual working memory capacity.
• Behavioral and CDA data suggested a tendency for balanced encoding of bilateral items.

Conclusions:

• The novel task effectively measures both NSW and CDA, offering converging neural insights into working memory.
• This paradigm provides a comprehensive approach to studying working memory using multiple EEG measures.
• The findings contribute to understanding the neural basis of visual working memory and its capacity.