Negative BOLD responses during hand and foot movements: An fMRI study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Negative BOLD signals in functional magnetic resonance imaging (fMRI) are associated with neural inhibition.
• Understanding these signals during motor execution provides insights into brain network dynamics.

Purpose of the Study:

• To characterize negative BOLD signal patterns during voluntary motor execution of hands and feet.
• To identify brain regions and networks involved in negative BOLD responses during movement.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Participants performed repetitive extension and flexion movements of the hand or ankle.
• Analysis focused on negative BOLD signal changes in specific brain regions.

Main Results:

• Negative BOLD responses were observed in the ipsilateral hemisphere's sensorimotor area (SMI) and frontal gyri (medial, middle, superior) during hand movements.
• Foot movements elicited negative BOLD responses in bilateral SMI, frontal gyri, and additional regions including the cingulate gyrus (CG) and precuneus.
• Conjunction analysis revealed common deactivation in medial frontal gyrus (MeFG) and CG, overlapping with default mode network regions, during both hand and foot movements.

Conclusions:

• Negative BOLD responses during voluntary movement involve at least three mechanisms: transcallosal inhibition, a broader deactivated network, and default mode network engagement.
• The findings highlight the complex interplay of inhibitory and network processes during motor control.