Brain Functional Connectivity Is Different during Voluntary Concentric and Eccentric Muscle Contraction.

Area of Science:

• Neuroscience
• Motor Control
• Human Physiology

Background:

• Previous research indicates greater cortical motor network activation during eccentric contractions (EC) compared to concentric contractions (CC), despite lower muscle activation during EC.
• The functional coupling strength between the primary motor cortex (M1) and other motor control regions during voluntary movements remains unclear.

Purpose of the Study:

• To investigate differences in functional connectivity (FC) between the primary motor cortex (M1) and associated cortical regions during EC and CC.
• To understand how the brain networks adapt to different muscle contraction types.

Main Methods:

• Functional magnetic resonance imaging (fMRI) data were collected from 11 healthy young adults during voluntary EC and CC of the right first dorsal interosseous (FDI) muscle.
• FC was estimated between M1 and other motor control network regions.
• Movement parameters (distance, speed, stability) were analyzed.

Main Results:

• No significant differences were observed in movement distance, speed, or stability between EC and CC.
• Significantly stronger mean functional connectivity (FC) was found during CC compared to EC.
• This suggests a more integrated neural network is involved in CC.

Conclusions:

• The study reveals that concentric muscle contractions involve stronger functional coupling within the motor network than eccentric contractions.
• These findings offer novel insights into the neural control mechanisms of voluntary movements.
• The results may inform the development of targeted training and therapeutic strategies for performance enhancement and injury prevention.