Dietz
Fakultäten » Medizinische Fakultät » Universitätsklinik Balgrist und Schweizerisches Paraplegikerzentrum » Paraplegikerzentrum » Prof. Dr. Armin Curt » Dietz
Completed research project
| Title / Titel | Probing neural circuitry for the control of movement: insights from stimulation studies | ||
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| Abstract (PDF, 14 KB) | |||
| Summary / Zusammenfassung | This project covers a wide-ranging study that has numerous sub-projects. The overall aim of these projects is to examine 1) the basic organization of spinal and cortical circuitry for the control of movement and 2) the influence of injury on these circuits. To investigate the neuronal circuitry, we will use various types of mechanical or electrical stimulation of the limbs in both uninjured human subjects and subjects with a neurological injury (such as spinal cord injury or Parkinson’s disease). The motor response to these various modes of stimulation will provide us with deeper knowledge about the basic neuronal circuitry underlying human movement and how it changes after neurological injury. Method: Electromyographic (EMG) recordings from the muscles of the legs and/or arms will be made in all investigations. During the experiments, subjects may be asked to either lie down (supine or prone), sit, stand, or walk on a treadmill. In addition, subjects may also be walking in a driven gait orthosis (Lokomat, Hocoma AG, Zurich Switzerland). The stimulation will be delivered at different times during the different static postures or during different movement phases, with a minimum inter-stimulus of 1 s. Electrical stimulation of peripheral nerves will be delivered via a commercially-available stimulator (AS100, ALEA Solutions GmBH, Zürich, Switzerland). Stimulation is delivered to the nerve via a surface electrode placed over the nerve of interest. The stimulator is a medically-rated component device that has been approved according to European standards (EN 61010-1: 1995, EN 50081-1: 1995, EN 50082-1 1995). The stimulator has 3 built-in safety features to prevent harm to the subjects. The intensity of the stimulus is controlled either with respect to a multiple of the lowest perceptual threshold (as reported by the subject) or with respect to the level of the associated motor response to the stimulus. Electrical stimulation may be applied either for cutaneous (skin) reflex studies, H-reflex studies, or flexor reflex afferent studies. For cutaneous reflex studies, the stimulus is typically on the order of 2-4 times the threshold of perception of radiating paraesthesia and is below that producing noxious responses. The actual intensity of the stimulation will differ depending on the individual subject, skin impedance, and electrode position. Typically the stimulus produces a sensation like a needle prick to the subject and may produce a visible muscle contraction. Stimulation of flexor reflex afferents involves more noxious stimulations. Low-intensity flexor reflex afferent responses are produced by stimulating cutaneous nerves (either behind the ankle or behind the knee) at intensities slightly higher than those used for cutaneous stimulation. Such stimulation produces a flexion response in the ipsilateral (stimulated) leg. High-intensity flexor reflex afferent responses involve activation of noxious pathways and produce a withdrawal response (analogous to the withdrawal response to painful stimuli). |
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| Keywords / Suchbegriffe | Spinal cord injury, degeneration, electrical stimulation | ||
| Project leadership and contacts / Projektleitung und Kontakte |
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| Funding source(s) / Unterstützt durch |
Others |
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| Duration of Project / Projektdauer | Nov 2004 to Nov 2011 |