Progressive Changes Between Thalamic Nuclei and Cortical Networks Across Stimulus-Response Learning

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Systems Neuroscience

Background:

• The thalamus is a key brain structure connecting cortical and subcortical regions, crucial for cognitive functions.
• Specific thalamic nuclei have unique connectivity patterns, but their roles in cognitive networks are not fully understood.
• Thalamic nuclei, like the mediodorsal nucleus, are implicated in goal-directed behaviors.

Purpose of the Study:

• To investigate changes in functional integration of thalamic nuclei within brain networks during the transition from controlled to automatic behavior.
• To examine how functional connectivity (FC) between thalamic nuclei, cortical, and subcortical structures evolves during learning in humans.

Main Methods:

• Functional magnetic resonance imaging (fMRI) data from 52 healthy subjects undergoing a stimulus-response learning task were analyzed.
• Regions-of-interest (ROIs) were defined for 47 thalamic nuclei, 38 basal ganglia/hippocampal subregions, and 12 cerebral cortex regions.
• ROI-to-ROI functional network analysis was used to examine learning-related FC changes.

Main Results:

• Learning decreased FC between the frontoparietal network and higher-order thalamic nuclei.
• Increased FC was observed between the cingulo-opercular network and pulvinar nuclei.
• Altered FC was found between the default mode network (DMN) and mediodorsal nuclei, alongside increased intrathalamic FC and changes involving the putamen.

Conclusions:

• Thalamic nuclei play a significant role in the neural basis of learning and behavioral automation.
• Functional connectivity patterns involving the thalamus dynamically adapt during the shift from controlled to habitual actions.
• These findings enhance our understanding of thalamocortical and thalamic-subcortical interactions in learning and behavior.