Corticospinal Excitability

De novo motor learning is a specific learning paradigm that allows investigation of how a new motor skill is learned from scratch. Motor task learning can induce increased corticospinal excitability and reorganization of connectivity observed within the motor cortex (M1). Several studies have investigated the plasticity mechanisms underlying motor learning using simple paradigms. The results obtained have been variable, with a major trend toward increased corticospinal excitability, while other results show no increase. We expect to observe a significant increase in excitability and enhanced intracortical reorganization mechanisms within M1 in our subjects during our de novo motor learning sessions. The primary objective of this study is to measure changes in corticospinal excitability of the motor system across 3 de novo motor learning sessions separated by different time intervals. The secondary objectives will be: 1) to measure learning across the three practice sessions, 2) to measure changes in inhibition and facilitation across the 3 learning sessions, and 3) to measure correlations between subjects' motor performance and corticospinal and intracortical changes.

Recent evidence suggests that cognitive systems do not operate in isolation but interact within broader networks, thus opening new avenues for fundamental and clinical research. An illustrative example is the interaction between language comprehension and motor representations. For instance, motor training (e.g., sports, origami training) can facilitate action verb recognition, whereas motor deficits (e.g., upper limb immobilization) can hinder the processing of action language. Similarly, action language has been shown to affect motor performance. These effects are attributed to an implicit form of motor imagery, an automatic simulation of motor experience (without actual movement) evoked by action words. Interestingly, literature supports the idea that the motor simulations used for imagining an action are also engaged during the reading of action language, leading to similar neurophysiological and behavioral changes in both processes. However, questions remain about the similarity of the simulations generated by motor imagery and action language. This project, encompassing three experimental sequences, aims to address these questions to achieve significant scientific advancements in both theoretical and applied domains.