Recent neurophysiological experiments have shown that the visual stimuli that trigger a particular kind of neurons located in the ventral premotor cortex of monkeys and humans are very selective. These textitmirror neurons are activated when the hand of another individual interacts with an objects but are not activated when the actions, identical in purpose, are made by manipulated mechanical tools. A Human Frontiers Science Program project is investigating which are the parameters of the external stimuli that mirror neurons visually extract and match on their movement related activity. The planned neurophysiological experiments will require the presentation of digital stimuli of different kinds, including video sequences showing meaningful actions made by human hands, synthetic reproductions of the same actions made by realistic virtual hands, as well as variations of the same actions by controlled modifications of hand geometry and/or action kinematics. This paper presents the specialized animation system we have developed for the project.