Exploring Cortical Reactivity and Connectivity during Bioartificial Motor Imagery and Pain/Itch processing: evidence from three Proof-Of-Concept TMS-EEG studies

The primary motor cortex (M1) is progressively recognized as a pivotal node where motor, sensory, and cognitive domains converge. Beyond its traditional motor role, M1 has shown to participate in higher-order cortical functions, such as motor imagery, having also a role in pain and itch processing. The present PhD work employs the combination of transcranial magnetic stimulation with electroencephalography (TMS–EEG) to explore cortical reactivity, con- nectivity and oscillatory dynamics of M1 across three proof-of-concept (PoC) studies concerning bio-artificial motor imagery, experimentally induced pain and itch. Twenty-four healthy volunteers were enrolled in a first study comparing natural and augmentative (robotic) grasping imagery, while two other studies of twelve subjects each respectively explored pain and itch cortical processing and pain interaction with motor imagery. As result, four TMS– EEG indices consistently pointed out decrease in both cortical reactivity and synchronization during motor imagery, pain and itch. Interestingly, the two motor imageries proposed (natural vs augmentative) exhibited different oscillatory patterns variations, while pain resulted in increasing beta2 frequency power, distinguishing it from itch. Although preliminary in nature, the current evidences then proved the feasibility and utility in using TMS–EEG for exploring sensorimotor dynamics, providing novel insights about bio-artificial motor imagery and cortical mechanisms differentiating pain from itch. Overall, this work highlights TMS–EEG as a promising tool for future, broader and more comprehensive investigations of sensorimotor system cortical mechanism.