Distinct neural mechanisms for spatially lateralized and spatially global visual working memory representations

Area of Science:

• Cognitive Neuroscience
• Electrophysiology
• Visual Perception

Background:

• Visual working memory (VWM) involves actively retaining limited information.
• Previous research identified lateralized event-related potentials (ERPs) for VWM maintenance.
• Recent imaging studies suggest spatially global visual cortex activity for VWM readout.

Purpose of the Study:

• To investigate the coexistence of lateralized and spatially global electrophysiological signatures in VWM.
• To determine if distinct neural mechanisms underlie these different VWM representations.

Main Methods:

• Simultaneous measurement of lateralized event-related potentials (ERPs) and parietooccipital alpha (8-12 Hz) power.
• Tracking VWM item counts using lateralized ERPs in one visual hemifield.
• Assessing spatially global VWM representations via bilateral alpha power.
• Decoding the identity of stored VWM representations from both ERP and alpha signals.

Main Results:

• Successfully measured coexisting lateralized ERPs and bilateral parietooccipital alpha power.
• Demonstrated that both alpha power and contralaterally biased ERPs carry decodable VWM information.
• Confirmed that these signals correlate with the number and identity of items in VWM.

Conclusions:

• Lateralized ERPs and bilateral alpha oscillations represent distinct neural mechanisms in VWM.
• ERPs map onto lateralized VWM representations, while alpha power reflects spatially global representations.
• Findings unify electrophysiological and imaging observations, suggesting parallel processing in VWM.