Influence of motor imagery of toe flexion using still images on the excitability of the spinal neural function

Abstract

As a pre-step to using motor imagery for functional training of patients with an increased likelihood of falling due to deterioration in toe grip function, the effect of motor imagery using still images was evaluated by F-waves, an index of the excitability of the spinal nerve function. The subjects were 15 healthy individuals (9 men, 6 women, average age 20.4 ± 1.5 years). The F-wave of the flexor muscle of the left great toe was measured in the resting state and, after learning the left toe flexion movement, the F-wave was measured again during the motor imagery task. The motor imagery task was an imagery trial performed with and without still images. The resting F-wave was recorded immediately after and 5, 10, and 15 minutes after both imagery trials. The amplitude of the F/M ratio of the imagery trial without still images was significantly increased compared with that of rest. In addition, there was no significant change in the amplitude of the F/M ratio of the image when using still images. When images are used for motor imagery, the excitability of the anterior horn cells of the spinal cord does not increase significantly. This is because the motor imagery execution reminds us of the sensation of motor execution, thereby prompting a clearer and more realistic motor image. Therefore, the influence of the images may be reduced.