Increased prefrontal activity and reduced motor cortex activity during imagined eccentric compared to concentric...

Area of Science:

• Neuroscience
• Motor Control
• Exercise Physiology

Background:

• Imagined resistance training involves complex neural processes.
• Understanding brain activation differences between concentric and eccentric muscle actions is crucial for motor control research.

Purpose of the Study:

• To investigate distinct brain region recruitment during imagined concentric versus eccentric phases of elbow flexor contractions.
• To explore the neural underpinnings of force regulation during imagined muscle actions.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed.
• Healthy young subjects performed an imagined maximum resistance training task of elbow flexors.
• Brain activity was analyzed during imagined concentric and eccentric phases.

Main Results:

• The pre-frontal cortex (BA44) showed bilateral recruitment during the imagined eccentric phase compared to the concentric phase.
• The motor and pre-motor cortex (BA 4/6) were recruited during the imagined concentric phase compared to the eccentric phase.
• Activity in the motor and pre-motor cortex was reduced during the eccentric phase relative to overall session activity.

Conclusions:

• Distinct neural mechanisms govern imagined concentric and eccentric contractions.
• Pre-frontal cortex recruitment during the eccentric phase may reflect increased force regulation demands.
• Reduced motor and pre-motor cortex activity during the eccentric phase might contribute to limitations in maximal eccentric muscle activation.