Program in Neuroscience, University of Fribourg, Switzerland
Dr. Dieter G. Ruegg
Institute of Physiology
University of Fribourg
1700 FRIBOURG
SWITZERLAND
phone +41-26-300 8608
email Dieter.Ruegg@unifr.ch
Website
Spinal motor control
The central nervous system's task of achieving controlled voluntary movements is an extraordinarily complex one. In most instances, numerous muscles are involved, each of which consists of at least one hundred motor units - the smallest entity which can be activated by the nervous system. Our objective is to discover the algorithms which the nervous system uses to activate motor units, muscles, muscle groups and spinal reflexes. Initially, we were concerned with the function of monosynaptic reflexes in the initiation of movements. Even in reaction time situation where the subject reacts as fast as possible, the reflex pathway is facilitated shortly before the onset of movement. As a first step towards unterstanding such interachtions between reflexes and voluntary muscle contractions, we have developed a time independent analytical model to describe muscle activation (in collaboration with the Institute of Mathematics), and we are currently engaged in testing it experimentally on human subjects. On the basis of predictions from the original model, we have elaborated a more sophisticated time dependent model with which we are now able to simulate not only the discharges and contractions of each motor unit within the activated muscle but also surface EMG. Another project in which we are involved relates to motor control in astronauts and cosmonauts after missions in the MIR station. These experiments are designed to assess the influence of microgravity on muscle activation, reflexes and the performance of reaction time tasks.
Selected publications
Drews H., Gerilovski L. & Ruegg D.G. Contribution of Ia muscle afferent activation to the rise of H reflexes and somatosensory evoked potentials in man. Somatosensory and Motor Research 5: 109-117, 1998
Ruegg D.G., Kakebeeke T.H. & Studer L.M. Activation of muscles and microgravity. International Journal of Sports Medicine 18:S329-S331, 1997
Studer L.M., Ruegg D.G. & Gabriel J.-P. A model for steady isometric muscle activation. Biological Cybernetics. 80: 339-355, 1999