Fronto-parietal homotopy in resting-state functional connectivity predicts task-switching performance

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Human Brain Imaging

Background:

• Homotopic functional connectivity measures interhemispheric synchrony.
• Previous research links altered brain homotopy and white matter integrity to cognitive decline.
• Task-switching performance is sensitive to age-related cognitive changes.

Purpose of the Study:

• To investigate the relationship between functional homotopy and task-switching performance in young adults.
• To examine how homotopy in fronto-parietal network nodes relates to cognitive demands during task-switching.
• To determine if task-switching performance is modulated by interhemispheric connectivity patterns.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure homotopic functional connectivity.
• Participants performed a task-switching paradigm with varying cue-to-target intervals (CTI: 300 ms and 1200 ms).
• Voxel-wise correlations were computed between functional homotopy and mixing costs within the fronto-parietal network and a control language network.

Main Results:

• Mixing costs, reflecting task-set maintenance, were significantly correlated with homotopy in fronto-parietal nodes.
• Lower homotopy in the superior frontal gyrus was associated with smaller mixing costs for short CTI trials.
• Lower homotopy in the supramarginal gyrus was associated with smaller mixing costs for long CTI trials.
• These correlations were specific to the fronto-parietal network, with no significant findings in the control language network.

Conclusions:

• Functional homotopy within the fronto-parietal network plays a role in task-switching performance.
• The specific fronto-parietal nodes involved and the nature of the relationship depend on cognitive demands, as modulated by CTI.
• These findings highlight a dissociable role of interhemispheric synchrony in cognitive control processes.