Purpose: 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.
Conclusion: Motor imagery facilitates the spinal motor neurons without hemispheric asymmetry.
From the *Department of Neurology, Showa University School of Medicine, Tokyo, Japan; †Division of Clinical Electrophysiology, Department of Neurology, University of Iowa Hospital and Clinics, Roy J. and Lucille A. Carver College of Medicine, Iowa, U.S.A.; ‡Department of Orthopedic Surgery, Kochi Medical School, Kochi; §Division of Neurology, Department of Medicine, Nihon University School of Medicine, Tokyo; ∥Department of Orthopedic Surgery, Kansai Medical University, Otokoyama Hospital, Kyoto; and ¶Department of Neurology, Tohoku University Hospital, Miyagi, Japan.
This study was presented in part at the 4th World Congress of the International Society of Physical and Rehabilitation Medicine, July 12th, 2008, Seoul, Korea.
Address correspondence and reprint requests to Hiroo Ichikawa, M.D., Department of Neurology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-Ku, Tokyo 142-8666, Japan; e-mail: firstname.lastname@example.org.