Exploring Information Flow from Posteromedial Cortex during Visuospatial Working Memory: A Magnetoencephalography...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Brain Imaging

Background:

• The posteromedial cortex (PMC) is a key component of the default mode network.
• Its exact role in internally driven cognitions, such as visuospatial working memory, is not fully understood.
• Understanding the PMC's function is vital for mapping brain interconnectivity and cognitive processes.

Purpose of the Study:

• To investigate the precise contribution of the PMC to visuospatial working memory.
• To analyze information flow and Granger-causal relationships between cortical regions during a visuospatial working memory task.
• To determine how the PMC influences stimulus representations in other brain areas.

Main Methods:

• Magnetoencephalography (MEG) was used to measure PMC activity in healthy young adults.
• Multivariate pattern classification analyzed stimulus-related information in predefined cortical regions of interest (ROIs).
• Information flow analysis quantified Granger-causal relationships between ROIs over time.

Main Results:

• Stimulus information was encoded and retrieved in prefrontal, occipital, ventrotemporal cortices, and PMC.
• Occipital cortex influenced other regions, consistent with the task's visual nature.
• The PMC significantly shaped object representations in occipital and prefrontal cortices throughout the task, particularly during retrieval.

Conclusions:

• Findings support the PMC's role in representing internal content and comparing external stimuli with memory.
• The PMC actively influences stimulus representations in other cortical regions during visuospatial working memory.
• This highlights the PMC's critical function in shaping cognitive processes during memory tasks.