Author/Editor		Schubert, M; Curt, A; Colombo, G; Berger, W; Dietz, V
Title		Visual control of human gait: a "functional" TMS study
Type		članek
Source		In: Stalberg EV, de Weerd AW, Zidar J, editors. ECCN 98. 9th European congress of clinical neurophysiology; 1998 Jun 4-7; Ljubljana. Bologna: Monduzzi Editore,
Publication year		1998
Volume		str. 143-7
Language		eng
Abstract		The aim of this study was to assess corticospinal input in human gait. It was assumed that visual input, as mediated via corticalpathways, should modulate evoked motor potentials (EMP) during walking. The effect of transcranial magnetic stimulation (TMS) in a visually guided precision stepping task was compared to that in normal gait. EMP were studied in tibialis anterior (TA), gastrocnemius (GM), and, for reference, in abductor digiti minimi (AD) muscles during treadmill walking. A significant modulation of net facilitation of EMP was demonstrable throughout thestride cycle in TA and GM when nromalizing the EMP with respect to the underlying electromyogram (EMG). Facilitation was strongest in TA particularly prior to an increase in EMG activity. Significant differences of EMP facilitation between the visual and control tasks could be seen in both, flexor and extensor. The profile of facilitation of TA EMP in the visual task was shifted in time to commence slightly earlier, yet, maximal facilitation prior to the swing phase was decreased compared to the control task. Conversely, there was increased facilitation of GM EMP during swing phase and particularly prior to the toe-down movement when the target was about to be touched. Thus, there was a differential effec of visual input upon EMP in TA and GM according to their respective functional state. During swing phase there was a reciprocal effect of inhibition and facilitation in the antagonists. The results support the initial hypothesis of a conditioning effect of volitional drive on the size of EMP during functional movement in the leg muslces. The possibility of clinical applicability of functional TMS in neurophysiological testing is discussed.
Descriptors		GAIT PSYCHOMOTOR PERFORMANCE EVOKED POTENTIALS, MOTOR NEUROPHYSIOLOGY ELECTROMYOGRAPHY