The brainstem's red nucleus was evolutionarily upgraded to support goal-directed action

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• The red nucleus, a brainstem structure, coordinates limb movement in quadrupeds.
• Human red nucleus connectivity differs from quadrupeds, suggesting a unique function.
• Previous functional neuroimaging of the human red nucleus was limited.

Purpose of the Study:

• To precisely examine human red nucleus functional connectivity using advanced resting-state functional connectivity (RSFC) and precision functional mapping (PFM).
• To elucidate the functional role of the human red nucleus beyond motor control.

Main Methods:

• Utilized highly sampled individuals (n=5) and large group-averaged datasets (N~45,000).
• Applied advanced RSFC-based PFM for precise brainstem functional neuroimaging.
• Examined functional connectivity patterns of the red nucleus.

Main Results:

• Minimal functional connectivity to somatomotor effector networks (hand, foot, mouth).
• Specific connectivity to the somato-cognitive action network (SCAN) along the central sulcus.
• Strongest connectivity outside primary motor cortex to cingulo-opercular (CON) and salience networks, organized into dorsal-medial and ventral-lateral zones.
• Connectivity to the thalamus mirrored the dento-rubral thalamic tract (DRTT), potentially aiding VIM nucleus targeting.

Conclusions:

• The human red nucleus is not solely a motor structure.
• It plays a crucial role in implementing goal-directed behavior by integrating behavioral valence and action plans.
• Findings suggest a revised understanding of the red nucleus's function in cognitive and motivational processes.