Right vagus nerve stimulation promotes motor cortical plasticity

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Neuroplasticity

Background:

• Left vagus nerve stimulation (l-VNS) paired with motor training improves post-stroke upper limb function.
• Preclinical studies suggest right vagus nerve stimulation (r-VNS) engages the dopaminergic reward system differently than l-VNS.
• This raises the possibility of r-VNS offering therapeutic advantages via enhanced plasticity or motivation.

Purpose of the Study:

• To investigate if r-VNS enhances VNS-driven motor cortical plasticity or behavioral performance compared to l-VNS.
• To compare the effects of r-VNS and l-VNS on motor learning and motivational circuits.

Main Methods:

• Healthy rats were trained on a stimulation-paired lever-pressing task.
• The study compared the effects of l-VNS and r-VNS on motor cortex representation expansion.
• Behavioral performance, including task engagement and accuracy, was assessed for both stimulation groups.

Main Results:

• Both l-VNS and r-VNS significantly expanded task-relevant motor cortex representations.
• No significant differences were observed between l-VNS and r-VNS in inducing cortical plasticity.
• Neither l-VNS nor r-VNS led to increased task engagement or performance accuracy in healthy rats.

Conclusions:

• The findings do not support the hypothesis that r-VNS offers benefits over l-VNS through differential engagement of motor learning or motivational circuits.
• Both r-VNS and l-VNS are effective in inducing cortical neuroplasticity.
• Cortical neuroplasticity induced by VNS is associated with enhanced stroke recovery.