Internal-external motor imagery and skilled motor actions

The purpose of this study was to analyze the movement-related brain macropotentials (MRBMs) recorded during the executions of two tests of motor imagery: kinaesthetic (internal) and visual (external).Recordings were compared with those obtained performing a GO/NO-GO motor test. The GO test required pressure of three keys of a modified keyboard in sequence when a figure appeared in the computer screen. On No/GO trials no button had to be pressed. Motor imagery tests were an internal or kinaesthetic imagination test (IN MI) on which partecipants imagined performing the pressure of keyboard buttons, avoiding any real movement, and an external or visual imagination test (EX MI) on wich subjects were asked to imagine seeing their finger press the buttons. With the completion of the Movement Imagery Questionnaire, the partecipants were assigned into two groups: high (11) and low (10) capacity of imagination. The experimental data confirm that real motor activity is related to higher amplitude MRBMs than motor imagery. The profile of the waves recorded during internal imagery seems to be related to a higher brain involvement compared to those recorded during external visual imagery; it suggest that the kinaesthetic process of imaginations is more efficient in information processing and motor skill acquisition.