Modellierung der Beteiligung spinaler Strukturen an der Handmuskelregelung beim Greifen

Kurzfassung

This thesis describes a model of spinal neuronal structures contributing to the control of muscle activity during grip. Gripping is a very complex task, although we do it uncountable times per day without thinking about it. During grips, 33 hand muscles have to be controlled based on rich sensory data. Visual information, cutaneous data and proprioceptive data have to be processed, activity of hand muscles is induced by alpha-motor neurons in the 7th and 8th vertebrae. Muscular activity is controlled using different control layers and can be induced by supraspinal structures in the brain’s motor cortex as well as by spinal structures. Proprioceptive information comes from the muscle spindles and the Golgi tendon organs and contains information about the position, movement speed and applied force of a muscle. It is conducted from the extremities to the corresponding region of the spine in several milliseconds, can be processed there and is conducted to the brain via ascending pathways. Proprioceptive information is processed by structures of spinal interneurons, which can activate and inhibit alpha- motor neurons and other interneurons as a very early reaction to stimuli. Activation of a muscle activates Renshaw cells, which can also interact with other interneurons and alpha-motor neurons. In this work a simplified computational model of the musculoskeletal system, proprioceptive organs and relevant spinal structures has been built. To validate the model, a test bed was constructed, with which fingers can be perturbed with predefined movements, while muscular activity can be recorded with surface EMG. The parameters of the spinal model can be fitted to the measured muscle activity.