Volitional muscle activation intensifies neuronal processing of proprioceptive afference in the primary sensorimotor cortex: an EEG study.

Proprioception refers to the ability to perceive the position and movement of body segments in space. The cortical aspects of the proprioceptive afference from the body can be investigated using corticokinematic coherence (CKC). CKC accurately quantifies the degree of coupling between cortical activity and limb kinematics, especially if precise proprioceptive stimulation of evoked movements are used. However, there is no evidence on how volitional muscle activation during the proprioceptive stimulation affects CKC strength. Twenty-five healthy volunteers (28.8 ± 7 yr, 11 females) participated the experiment that included electroencephalographic (EEG), electromyographic (EMG) and kinematic recordings. 2-Hz ankle-joint rotations were elicited through a movement actuator in two conditions: