Mirror systems: evolving imitation and the bridge from praxis to language

Abstract

The Mirror System Hypothesis of the evolution of the human language-ready brain emphasizes the parity requirement for communication through language. It gives key roles to mirror neurons for manual actions and the evolution of brain mechanisms for an imitation of the praxis. Both the imitation and language require integration of mirror neurons with diverse neural systems. The visual data on shape and pose of an object are processed in parietal cortex and passed to an area of the premotor cortex called F5. Many single neurons in F5 fire most strongly when the monkey executes a limited range of manual actions, with distinct neurons related to such as a precision pinch, tearing paper, or breaking peanuts. The Mirror System Hypothesis holds that the brain mechanisms, which support language, evolved in part by an elaboration of Broca's area atop the mirror system for manual action. The Mirror System Hypothesis has several elements such as language demands parity and mirror neurons provide a basis for parity. The hominin evolution mentions that mirror neurons for manual actions preceded those for vocal actions, thereby lending support to gestural theories of language origin. Ape gestures are flexible and learnable, in contrast to the mostly innate system of primate vocalizations, exemplifying processes whereby a practical action may become ritualized to serve as a communicative action. Imitation is essential for language and mirror neurons are essential for imitation but do not support imitation in and of themselves.