Shared functional connectivity between the dorso-medial and dorso-ventral streams in macaques

Area of Science:

• Neuroscience
• Motor Control
• Functional Connectivity

Background:

• Object manipulation involves distinct reach and grasp actions.
• Traditionally, reach and grasp are thought to be processed in separate brain streams.
• Recent evidence questions this strict separation.

Purpose of the Study:

• To investigate the whole-brain functional connectivity of reach and grasp processing areas.
• To examine the validity of the two-stream hypothesis for sensorimotor processing.
• To identify shared and distinct network connections in macaques.

Main Methods:

• Used resting-state functional magnetic resonance imaging (fMRI) at 7-Tesla.
• Analyzed whole-brain functional connectivity in 10 male rhesus macaques.
• Focused on key areas within the dorso-medial (reach) and dorso-ventral (grasp) streams.

Main Results:

• Confirmed a functional separation between dorso-medial and dorso-ventral networks.
• Identified distinct correlations: dorso-ventral with somatosensory/feeding areas, dorso-medial with visual/trunk-hindlimb motor areas.
• Revealed shared connectivity in areas including the superior frontal gyrus, precentral gyrus, and intraparietal sulcus.

Conclusions:

• Sensorimotor processing streams for reach and grasp are largely functionally separated.
• These separate streams can access information through commonly connected brain regions.
• Suggests a more integrated model of motor control than previously assumed.