Pitching-specific facilitation of upper-limb corticospinal excitability during motor imagery of sports motor skills

Comprehensive Summary

This paper explores how motor imagery (MI), defined as the mental stimulation of movement without actual physical movement, affects corticospinal excitability during motor tasks such as baseball, tennis, and basketball. While previous methods, such as transcranial magnetic stimulation, were used to study neural activation, motor imagery is a more efficient and detailed way to understand how the motor system shows physical activity at the cortical level. To represent this, two experiments were conducted: in the first, five sports movements were performed without visual input; in the second, participants repeated the imagery tasks while watching videos of each movement, allowing the researchers to assess whether visual guidance enhances neural activation. The corticospinal excitability was measured using TMS-induced motor potentials in the flexor carpi radialis (FCR), extensor carpi radiologist (ECR), first dorsal interosseous (FDI), and abductor pollicis brevis (APB). Testing these four upper-limb sections showed that only the MEP amplitude increased by 182% during baseball pitching in Experiment 1, whereas in Experiment 2, APB increased by 131% and FCR by 152%, indicating that visual-guided imagery enhanced neural activation. According to the researchers, because the background EMG activity remained the same, this confirmed that the percent increase in muscle activity was due to neural modulation rather than involuntary muscle contraction. Using motor imagery yields more precise, relevant motor representations rather than generalized activation of the motor cortex, and these representations are especially enhanced by visual guidance.

Outcomes and Implications

The use of motor imagery is important medically because it demonstrates that MI can selectively activate neural pathways associated with fine motor control, even in the absence of physical movement. This can have significant implications for neurological rehabilitation, specifically when patients are recovering from motor depleted and degeneration disorders like stroke or traumatic brain injury. Since MI was shown to enhance corticospinal excitability in specific muscles critical to task performance, it could be used to target weakened motor pathways early in recovery, including in patients who are not yet capable of performing physical exercises. Additionally, by testing fine motor skills through the use of sports like baseball pitching, MI paired with visual guidance can modulate corticospinal output and provide a noninvasive approach to retraining motor planning without triggering dysfunctional movement patterns. According to the researchers, further research is required to test the use of motor imagery clinically, however the results indicate that MI can be implemented in rehabilitation settings due to its precision and accessibility.