Enhanced intersubject similarity in functional connectivity by long-term abacus training

Area of Science:

• Neuroscience
• Cognitive Science
• Brain Imaging

Background:

• Individual differences in intrinsic functional connectivity (FC) are biologically informative and behaviorally relevant.
• Previous cognitive training studies often overlooked individual FC differences, treating them as random variation.
• Abacus-based mental calculation (AMC) training offers a unique model to study long-term cognitive plasticity.

Purpose of the Study:

• To investigate the plasticity of intersubject similarity in functional connectivity (ISFC) induced by long-term AMC training.
• To identify specific functional connections ('critical FCs') affected by AMC training.
• To explore the relationship between enhanced ISFC and mental calculation ability.

Main Methods:

• Longitudinal study: Compared ISFC changes in AMC trainees (n=40, 5-year training) versus controls (n=43).
• Cross-sectional study: Examined ISFC and its predictive power in a larger sample (AMC: n=93; Control: n=110) with varying training durations (1-5 years).
• Functional connectivity (FC) analysis using neuroimaging data to assess brain network similarities.

Main Results:

• AMC training robustly enhanced ISFC, even after accounting for developmental factors.
• The ISFC enhancement was specific to 'critical FCs,' primarily within the default-mode and visual networks.
• In the AMC group, 'critical FCs' and their intersubject similarity predicted mental calculation ability and its similarity, a relationship not observed in controls.

Conclusions:

• Long-term AMC training induces plastic changes in ISFC, particularly impacting the default-mode network.
• Enhanced ISFC is associated with behavioral improvements in mental calculation ability.
• Long-term cognitive training may be necessary to establish robust brain-behavior relationships linked to functional connectivity patterns.