Correlati EEG dell’osservazione di azioni. Integrazione visuo-motoria e osservazione di performance motorie sub-ottimali

[Autom. eng. transl.] Several evidences in the literature have shown how the observation of actions can increase the activation of the sensorimotor system. This effect has been traced to priming and facilitating neural responses. In addition, it has been observed that the processes of visual-motor facilitation and observation of actions can be influenced by experience. The role of experience was, however, mainly studied by focusing investigations on motor acts that require high levels of competence (eg dance). Consequently, while it has been shown that the observation of technical gestures that have been the object of training induces greater motor responsiveness in groups of athletes, there are still no consolidated data on the possible effects of observing impaired motor performance. These effects have been investigated with a first non-invasive brain stimulation study (TMS - Transcranial Magnetic Stimulation), which showed that the responsiveness of the motor cortex can also be modulated by sub-optimal motor performance vision. In order to investigate these evidences, a second study was carried out by which to investigate the electrophysiological correlates (EEG) of the observation of complex actions performed by individuals with and without motor difficulties. 20 volunteers took part in the EEG study and observed several video clips in which an actor performed the Nine-Hole Peg Test, a standardized motility task. The task could be performed by a confederate without movement difficulties, by a patient suffering from multiple sclerosis with mild motor deficits, by a patient suffering from multiple sclerosis with moderate motor deficits, or by a confederate who tried to simulate mild motor deficits. The analysis of power data for the main EEG frequency bands showed a general decrease in the prevalence of beta band activity during observation of impaired motor performance, but only if real and not simulated. In addition, at the somatosensory areas, the beta power presented a progressive increase associated with the repetition of stimuli, particularly evident with regard to the video of the patient with slight motor difficulties. In line with the functional reading of beta oscillations, these evidences suggest the presence of a progressive integration of sub-optimal motor performances in the motor patterns of the observers, a phenomenon attributable to the intrinsic sensitivity and responsiveness of the human sensorimotor system.