Premium
Facilitation of corticospinal excitability in the tibialis anterior muscle during robot‐assisted passive stepping in humans
Author(s) -
Kamibayashi Kiyotaka,
Nakajima Tsuyoshi,
Takahashi Makoto,
Akai Masami,
Nakazawa Kimitaka
Publication year - 2009
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2009.06795.x
Subject(s) - transcranial magnetic stimulation , biceps , tibialis anterior muscle , motor cortex , stimulation , neuroscience , facilitation , physical medicine and rehabilitation , corticospinal tract , afferent , electromyography , pyramidal tracts , treadmill , psychology , medicine , anatomy , physical therapy , magnetic resonance imaging , skeletal muscle , radiology , diffusion mri
Although phasic modulation of the corticospinal tract excitability to the lower limb muscles has been observed during normal walking, it is unclear to what extent afferent information induced by walking is related to the modulation. The purpose of this study was to test the corticospinal excitability to the lower limb muscles by using transcranial magnetic stimulation (TMS) and transcranial electrical stimulation of the motor cortex while 13 healthy subjects passively stepped in a robotic driven‐gait orthosis. Specifically, to investigate the effect of load‐related afferent inputs on the corticospinal excitability during passive stepping, motor evoked potentials (MEPs) in response to the stimulation were compared between two passive stepping conditions: 40% body weight unloading on a treadmill (ground stepping) and 100% body weight unloading in the air (air stepping). In the rectus femoris, biceps femoris and tibialis anterior (TA) muscles, electromyographic activity was not observed throughout the step cycle in either stepping condition. However, the TMS‐evoked MEPs of the TA muscle at the early‐ and late‐swing phases as well as at the early‐stance phase during ground stepping were significantly larger than those observed during air stepping. The modulation pattern of the transcranial electrical stimulation‐evoked MEPs was similar to that of the TMS‐evoked MEPs. These results suggest that corticospinal excitability to the TA is facilitated by load‐related afferent inputs. Thus, these results might be consistent with the notion that load‐related afferent inputs play a significant role during locomotor training for gait disorders.