Spinal plasticity with motor imagery practice.

Area of Science:

• Neuroscience
• Motor Control
• Neuroplasticity

Background:

• Motor imagery (MI) is the mental simulation of movement without physical execution.
• While MI's effects on cortical areas are established, its impact on spinal structures is less understood.
• Investigating MI's influence on spinal mechanisms is crucial for understanding neural plasticity.

Purpose of the Study:

• To assess the plastic changes in spinal structures following an acute session of motor imagery practice.
• To examine the effect of MI on spinal presynaptic inhibition and Ia-afferent motoneuronal excitability.
• To determine if MI practice modulates spinal circuitry sensitivity.

Main Methods:

• Utilized H-reflex conditioning paradigms to evaluate spinal presynaptic inhibition and facilitation.
• Compared triceps surae spinal H-reflex responses (H_TEST, H_PSI, H_FAC) before and after a 20-minute MI practice session.
• Included a 20-minute rest session as a control.

Main Results:

• MI practice significantly increased H_PSI and H_FAC responses, indicating a reduction in spinal presynaptic inhibition.
• No significant changes were observed in the unconditioned H_TEST response or afferent-motoneuronal synapse.
• These changes were observed immediately after MI practice and persisted for at least 10 minutes.

Conclusions:

• Acute motor imagery practice induces short-term plasticity in spinal circuitry.
• MI practice reduces spinal presynaptic inhibition, thereby increasing the sensitivity of the spinal cord to MI.
• Findings suggest that spinal network modulation is a component of the neural plasticity induced by MI practice.