When observing others we usually do not require a verbal explanation to understand what they are doing and, in many cases, why they are doing it. Specific brain regions are involved in the processing of observed actions and some of them belong to the motor system, which is mainly involved in the planning and production of movements. Intensive research of these regions suggests, that the same neurons are active during action observation and execution. It has been proposed that these neurons, so called mirror neurons, allow the simulation of observed actions in a person’s motor system. This simulation may help to understand the actions of others. This theory of motor simulation is an intriguing way to explain certain aspects of action perception, as learning by observation, but many questions remain, some of which have been addressed in this thesis