The mirror-neurons system: data and models

In this chapter we discuss the mirror-neurons system, a cortical network of areas that enables individuals to understand the meaning of actions performed by others through the activation of internal representations, which motorically code for the observed actions. We review evidence indicating that this capability does not depend on the amount of visual stimulation relative to the observed action, or on the sensory modality specifically addressed (visual, acoustical). Any sensorial cue that can evoke the "idea" of a meaningful action activates the vocabulary of motor representations stored in the ventral premotor cortex and, in humans, especially in Broca's area. This is true also for phonoarticulatory actions, which determine speech production. We present also a model of the mirror-neurons system and its partial implementation in a set of two experiments. The results, according to our model, show that motor information plays a significant role in the interpretation of actions and that a mirror-like representation can be developed autonomously as a result of the interaction between the individual and the environment.