Ehrsson, H. H., Geyer, S., & Naito, E. (2003). Imagery of voluntary movement of fingers, toes, and tongue activates corresponding body-part-specific motor representations. Journal of Neurophysiology, 90, 3304-3316.

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This article reviews much of the research that has originated with new technologies (developed over the last 20 years) that allow the functioning of the brain to be viewed and mapped as real and imagined movement actions occur. It also tests the hypothesis that both real and imagined motor activities stimulate similar representations in the brain.

"The essential component of motor imagery is that the subject imagines himself or herself to be executing the action from the first-person perspective" (p. 304). While some studies report third person imagery (i.e., watching a movie of oneself) to be the best for learning or improving form sports, the majority of highly practiced and natural activities should be first-person oriented to stimulate the actual mental maps of those activities.

"During motor imagery, memory information related to previous enactments is retrieved. It has been suggested that these 'motor memories' are stored in the motor system. . . it has been a common view that motor imagery corresponds to a type of motor preparation process where motor programs are recruited to simulate motor performances without executing the movements. . . [This is] the 'simulation hypothesis' [the hypothesis tested in this investigation]. "Psychophysical experiments have shown that imagined movements seem to obey the same 'motor rules' (e.g., speed-accuracy trade-off) and biomechanical constraints as real movements"(p. 304).

"An important prediction of the simulation hypothesis is that imagery of different types of movement should engage the different corresponding motor representations" (p. 305). Healthy Ss (M = 6; F = 1) performed three motor (move fingers; move toes; and move tongue) and three imagined movements, each separated by identical rest conditions. Brain function was observed using magnetic resonance imaging and electromyography was used to analyze muscular functions in the fingers and toes.

It was found that imagery of the voluntary movement of a particular limb activates specific somatotopically organized motor representations in sections of the motor cortices of real movements. The simulation hypothesis was supported.

Implication. The exact imagination of a movement has the potential to reinforce the movement pattern elicited. The imagery must contain all the features of the movement (the sensations from a first-person perspective, and all movement qualities speed, effort, and scope). The insertion of new movement elements offers an opportunity to improve the movement, although it has not actually been executed. The downside of such "mental tinkering" is that if the new elements are incorrect, performance will decrease.

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