Functional network mirrored in the prefrontal cortex, caudate nucleus, and thalamus: high-resolution functional...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Human Brain Imaging

Background:

• Cortico-striatal-thalamo-cortical loops are crucial for cognitive functions.
• Previous research suggested parallel organization but lacked direct evidence in healthy humans.

Purpose of the Study:

• To investigate the functional specificity and structural connectivity of cortico-subcortical loops in the human brain.
• To examine how these loops vary with cognitive hierarchy levels in different domains.

Main Methods:

• Utilized high-resolution functional magnetic resonance imaging (fMRI) and diffusion-weighted magnetic resonance imaging (dMRI) at 7 tesla.
• Implemented three levels of cognitive hierarchy in second language and nonlanguage tasks.
• Analyzed brain activation patterns and structural connectivity using tractography.

Main Results:

• Distinct activation patterns were observed in the prefrontal cortex (PFC), caudate nucleus (CN), and thalamus (VA/MD) corresponding to higher and lower cognitive hierarchy levels.
• fMRI showed anterior PFC, CN head, and VA thalamus for higher levels, and posterior PFC, CN body, and MD thalamus for lower levels.
• dMRI tractography confirmed parallel structural connections mirroring the functional specificity of these loops.

Conclusions:

• This study provides the first in vivo human evidence of parallel cortico-subcortical loops with functional specificity.
• The findings demonstrate that functional specificity within these loops is mirrored by parallel structural networks.
• These results advance our understanding of brain organization underlying cognitive processes.