N-back task revisited: Comparing the neural correlates of updating and interference control

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Working memory relies on specialized systems for executive functions like updating and interference control.
• Understanding these processes is vital for psychological resilience and mental health.

Purpose of the Study:

• To delineate neural correlates of updating and interference control using the n-back task.
• To compare neural responses to targets and lures under varying cognitive loads.
• To investigate brain network connectivity differences between these executive functions.

Main Methods:

• fMRI scans of 159 healthy young adult females performing a verbal n-back task.
• Analysis of predefined regions-of-interest (ROIs): middle frontal gyrus (MFG), inferior frontal gyrus (IFG), anterior insula, and caudate.
• ROI and voxel-wise activation analyses, alongside seed-to-voxel connectivity analyses.

Main Results:

• Updating and interference control share overlapping brain networks but exhibit unique patterns.
• MFG and caudate showed stronger activation and differential connectivity for targets versus lures.
• Load-dependent effects showed increased cortical and decreased subcortical activation for targets, with the opposite for lures.
• Targets demonstrated left lateralization, while lures showed right lateralization.

Conclusions:

• The study uncovers nuanced neural dynamics of updating and interference control in female verbal working memory.
• Highlights the interplay between cortical and subcortical regions and their integration under cognitive demand.
• Provides insights into the neural basis of executive functions crucial for mental health.