Abstract
In normal muscle, the many muscle fibers belonging to each motor unit intermingle in a mostly random fashion with those of other motor units, which may be of the same or opposite type. Denervation, with subsequent reinnervation, is known to lead to reorganization of this intermingling, and to fiber type grouping. The details of this process are not well understood. A computer model of muscle fiber spatial distribution has been developed to allow the investigation of motor unit reorganization occurring during the process of denervation-reinnervation.
With this model a study was conducted in which certain model parameters were varied. Motor units were gradually killed and fiber type grouping was measured with the newly developed Co-Dispersion Index (CDI). Comparison of the plots for CDI vs. percent motor unit death showed the insensitivity of the CDI to the parameters in question.