Motor program coding representation from a handwriting generator model: The production of line responses

In this paper, a model is employed that describes handwriting behaviors activated by curvilinear and angular velocity generators postulated to initiate and regulate pen tip velocity profiles. This model accounts for the observed differences between straight and curved line production and the effect of movement precues on these responses. Of particular interest is the observed interaction between precue information and line execution type for reaction time. It is shown that differences in reaction time can be explained by the model as a function of the number of parameters that need to be specified. Moreover, there is some evidence that the biomechanical system reacts in a privileged manner to command pulses for specific directions, and that the central nervous system attempts to compensate for these asymmetries. These data are some of the first to show that the benefits of precue extend beyond reaction time and that movement execution characteristics are influenced by motor preparation.