Motor imagery facilitates the spinal motor neurons without hemispheric asymmetry.
OBJECTIVE
To determine possible hemispheric differences of motor imagery in facilitating the anterior horn cells.


METHODS
We conducted a side-to-side comparison of motor imagery to counter rest-induced suppression of spinal motor neurons in 10 right-handed healthy adults using the F wave as a measure of excitability. Studies consisted of sequential recording of F waves from the abductor pollicis brevis with 100 supramaximal stimuli applied to the median nerve on three consecutive sessions: (1) after standardized hand exercise to establish the baseline; (2) after immobilizing abductor pollicis brevis bilaterally for 3 hours, with one side assigned to relaxation task and the other side to motor imagery task; and (3) after standardized hand exercise to assess a recovery. The same sequence was repeated, switching the side of relaxation and motor imagery tasks.


RESULTS
F-wave persistence and average amplitude showed a significant decrease (P < 0.01) from baseline after relaxation task, recovering quickly after exercise, but no change (P > 0.05) after motor imagery task. The results showed no significant differences (P > 0.05) between dominant and nondominant hands.


CONCLUSIONS
Motor imagery facilitates the spinal motor neurons without hemispheric asymmetry.
Ichikawa
Hiroo
H
Department of Neurology, Showa University School of Medicine, Tokyo, Japan. h_ichikawa0527@yahoo.co.jp
Kimura
Jun
J
Taniguchi
Shinichirou
S
Hara
Motohiko
M
Fujisawa
Reiko
R
Shimizu
Hiroshi
H
Yamada
Thoru
T
Kawamura
Mitsuru
M
D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006225:Hand / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D008475:Median Nerve / Q000502:physiology; D008875:Middle Aged; D009043:Motor Activity; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D010865:Pilot Projects; D012063:Relaxation / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D055815:Young Adult