Proprioceptive information allows humans to perform smooth coordinated movements by constantly updating one's mind with knowledge of the position of one's limbs in space. How this information is combined with other sensory modalities and centrally processed to form conscious perceptions of limb position remains relatively unknown. What has proven even more elusive is pinpointing the contribution of proprioception in cortical activity related to motion. This study addresses these gaps by examining electrocortical dynamics while participants performed an upper limb position matching task in two conditions, namely with proprioceptive feedback or with both visual and proprioceptive feedback. Specifically, we evaluated the reduction of the electroencephalographic power (desynchronization) in the μ frequency band (8–12 Hz), which is known to characterize the neural activation associated with motor control and behavior. We observed a stronger desynchronization in the left motor and somatosensory areas, contralateral to the moving limb while, parietal and occipital regions, identifying association and visual areas, respectively, exhibited a similar activation level in the two hemispheres. Pertaining to the influence of the two experimental conditions it affected only movement's offset, and precisely we found that when matching movements are performed relying only on proprioceptive information, a lower cortical activity is entailed. This effect was strongest in the visual and association areas, while there was a minor effect in the hand motor and somatosensory areas.

Cerebral palsy (CP) is a group of non-progressive developmental movement disorders inducing a strong brain reorganization in primary and secondary motor areas. Nevertheless, few studies have been dedicated to quantify brain pattern changes and correlate them with motor characteristics in CP children. In this context, it is very important to identify feasible and complementary tools able to enrich the description of motor impairments by considering their neural correlates. To this aim, we recorded the electroencephalographic activity and the corresponding event-related desynchronization (ERD) of a group of mild-to-moderate affected unilateral CP children while performing unilateral reach-to-grasp movements with both their paretic and non-paretic arms. During paretic arm movement execution, we found a reduced ERD in the upper µ band (10-12.5 Hz) over central electrodes, preceded by an increased fronto-central ERD in the lower µ band (7.5-10 Hz) during movement preparation. These changes positively correlated, respectively, with the Modified House Classification scale and the Manual Ability Classification System. The fronto-central activation likely represents an ipsilesional plastic compensatory reorganization, confirming that in not-severely affected CP, the lesioned hemisphere is able to compensate part of the damage effects. These results highlight the importance of analyzing different sub-bands within the classical mu band and suggest that in similar CP population, the lesioned hemisphere should be the target of specific intensive rehabilitation programs.

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