Soleus Hoffmann reflex amplitudes are specifically modulated by cutaneous inputs from the arms and opposite leg during walking but not standing

Author(s)

Suzuki, Shinya ^{[1, 2]} ; Nakajima, Tsuyoshi ^[2] ; Futatsubashi, Genki ^{[1, 3]} ; Mezzarane, Rinaldo A. ^{[4, 5, 6]} ; Ohtsuka, Hiroyuki ^[7] ; Ohki, Yukari ^[2] ; Zehr, E. Paul ^{[8, 9, 10]} ; Komiyama, Tomoyoshi ^{[1, 6]}

Affiliation

^[1] Tokyo Gakugei Univ, United Grad Sch Educ, Div Hlth & Sports Educ, Tokyo - Japan

^[2] Kyorin Univ, Dept Integrat Physiol, Sch Med, 6-20-2 Shinkawa, Mitaka, Tokyo 1818611 - Japan

^[3] Jobu Univ, Fac Business & Informat Sci, Gunma - Japan

^[4] Univ Brasilia, Coll Phys Educ, Lab Signal Proc & Motor Control, Brasilia, DF - Brazil

^[5] Univ Sao Paulo, Biomed Engn Lab, EPUSP, PTC, Sao Paulo - Brazil

^[6] Chiba Univ, Div Hlth & Sports Sci, Fac Educ, Chiba - Japan

^[7] Hlth Sci Univ Hokkaido, Dept Phys Therapy, Sch Rehabil Sci, Tobetsu, Hokkaido - Japan

^[8] Univ Victoria, Rehabil Neurosci Lab, Victoria, BC - Canada

^[9] Univ Victoria, Ctr Biomed Res, Victoria, BC - Canada

^[10] Int Collaborat Repair Discoveries ICORD, Vancouver, BC - Canada

• Document type: Journal article
• Source: Experimental Brain Research; v. 234, n. 8, p. 2293-2304, AUG 2016.
• Web of Science Citations: 3

Abstract

Electrical stimulation of cutaneous nerves innervating heteronymous limbs (the arms or contralateral leg) modifies the excitability of soleus Hoffmann (H-) reflexes. The differences in the sensitivities of the H-reflex pathway to cutaneous afferents from different limbs and their modulation during the performance of motor tasks (i.e., standing and walking) are not fully understood. In the present study, we investigated changes in soleus H-reflex amplitudes induced by electrical stimulation of peripheral nerves. Selected targets for conditioning stimulation included the superficial peroneal nerve, which innervates the foot dorsum in the contralateral ankle (cSP), and the superficial radial nerve, which innervates the dorsum of the hand in the ipsilateral (iSR) or contralateral wrist (cSR). Stimulation and subsequent reflex assessment took place during the standing and early-stance phase of treadmill walking in ten healthy subjects. Cutaneous stimulation produced long-latency inhibition (conditioning-test interval of similar to 100 ms) of the H-reflex during the early-stance phase of walking, and the inhibition was stronger following cSP stimulation compared with iSR or cSR stimulation. In contrast, although similar conditioning stimulation significantly facilitated the H-reflex during standing, this effect remained constant irrespective of the different conditioning sites. These findings suggest that cutaneous inputs from the arms and contralateral leg had reversible effects on the H-reflex amplitudes, including inhibitions with different sensitivities during the early-stance phase of walking and facilitation during standing. Furthermore, the differential sensitivities of the H-reflex modulations were expressed only during walking when the locations of the afferent inputs were functionally relevant. (AU)

• FAPESP's process: 12/05304-5 - Effects of cutaneous activation on contralateral reflex modulation during gait in humans
• Grantee: Rinaldo André Mezzarane
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor