Interindividual differences in functional interactions among prefrontal, parietal and parahippocampal regions during...

Area of Science:

• Cognitive Neuroscience
• Neuroimaging
• Brain Systems Analysis

Background:

• Understanding individual variations in neural systems underlying working memory (WM) is crucial.
• Previous research often averages brain activity, masking inter-individual differences in cognitive tasks.
• The specific neural networks engaged during 2-back WM tasks and their relation to performance remain incompletely understood.

Purpose of the Study:

• To elucidate the distinct neural systems employed by individual subjects during a 2-back working memory task.
• To investigate the relationship between performance level, self-reported strategies, and neural network configurations.
• To explore inter-individual variance in neural patterns using structural equation modeling (SEM).

Main Methods:

• Functional neuroimaging data (fMRI) were collected from healthy participants performing a 2-back WM task.
• Structural Equation Modeling (SEM) was used to construct a group-level model and individual subject models.
• Correlation analysis examined the relationship between performance, strategy scores, and network path weights.

Main Results:

• A group model highlighted prefrontal and parietal cortex involvement, with significant inter-individual variability.
• High performers showed a left-hemisphere network (inferior parietal lobule, Broca's area); lower performers used a right-hemisphere network (inferior parietal lobule, dorsolateral prefrontal cortex).
• An interaction between parahippocampal formation and inferior parietal lobule correlated with strategy differences; verbal processing networks yielded better performance than spatial ones.

Conclusions:

• Individual behavioral characteristics, including performance and strategy, are reflected in specific neurofunctional system-level patterns.
• SEM effectively captures these strategy- and performance-related neural variations in working memory.
• Neural systems supporting verbal processing are associated with superior performance in this 2-back task compared to spatial processing systems.