Connectivity properties in the prefrontal cortex during working memory: a near-infrared spectroscopy study

Area of Science:

• Neuroscience
• Cognitive Science
• Brain Network Analysis

Background:

• Working memory (WM) is vital for cognitive functions.
• Brain connectivity analysis offers insights into WM network properties.
• Combining functional and effective connectivity provides a comprehensive view of brain networks.

Purpose of the Study:

• To investigate prefrontal cortex (PFC) connectivity during working memory tasks using combined functional and effective connectivity analysis.
• To explore how network properties change with increasing memory load (0-back vs. 2-back tasks).

Main Methods:

• Utilized near-infrared spectroscopy (NIRS) to measure brain activity.
• Applied functional and effective connectivity analyses, including Granger causality (GC).
• Examined network properties like characteristic path length and clustering coefficient in the PFC.

Main Results:

• The PFC network exhibited small-world properties in both 0-back and 2-back tasks.
• Characteristic path length increased significantly with higher memory load (2-back vs. 0-back).
• Effective connectivity showed increased Granger causality from right PFC to left PFC in the 2-back task.

Conclusions:

• Increased working memory load enhances long-range connections within the PFC.
• The observed enhancement in connectivity, particularly right to left PFC information flow, may support higher memory demands.