EEG markers of successful allocentric spatial working memory maintenance in humans

Area of Science:

• Neuroscience
• Cognitive Psychology
• Electrophysiology

Background:

• Allocentric spatial working memory is vital for navigation and daily tasks.
• The specific brain oscillatory patterns supporting human allocentric spatial working memory remain unclear.
• Previous research implicates various brain regions but lacks focus on oscillatory dynamics.

Purpose of the Study:

• To investigate the electroencephalographic (EEG) oscillatory patterns associated with successful versus failed allocentric spatial working memory maintenance in humans.
• To compare these patterns between young and older adults.

Main Methods:

• Twenty-three young and twenty-two older adults performed a real-world spatial working memory task.
• Electroencephalographic (EEG) activity was recorded during the memory maintenance period.
• Individual alpha frequency-based analyses and exact low-resolution brain electromagnetic tomography in the frequency domain were employed to analyze oscillatory power in perfect and failed recall trials.

Main Results:

• Theta band relative power was significantly higher in successful (perfect) trials compared to failed trials, particularly in frontal midline and posterior regions.
• Gamma band (30-40 Hz) relative power was also greater in perfect trials over the right motor cortex.
• Source localization revealed increased theta power in the secondary visual area (BA19) and increased gamma power in the right supplementary motor area (BA6) during successful memory maintenance.

Conclusions:

• Theta oscillations in the occipital lobe are implicated in successful allocentric spatial working memory maintenance.
• Gamma oscillations in the secondary motor cortex (BA6) are also associated with effective spatial working memory performance.
• These findings highlight the role of specific oscillatory frequencies in distinct brain regions for successful spatial memory recall.