Mirror neurons have been one of the most exciting neurological discoveries in recent years. Some researchers have even gone as far as comparing the discovery of mirror neurons to DNA. Mirror neurons may be analogous to other human sensory systems and some believe that mirror neurons represent their own unique sensory system. Mirror neurons fire when a person or animal performs certain activities as well as when they watch another perform the same activity (Winerman, 2005). Basically, they allow animals and humans to imitate and possibly even learn from others. While the original studies were conducted in monkeys, recent research has extended the theory to humans and other abilities outside of basic motor movements. In this paper, research on mirror neurons in humans, language, and autism will be summarized. In addition, the limitations on this work will be discussed.
The widely popular research on mirror neurons and various applications of the research findings began with an important, but unexpected finding in the brains of macaque monkeys. The original studies did not intend to look at mirror neurons and in fact the existence of mirror neurons was found by accident. Neuroscientist Giacomo Rizzolatti and his colleagues found a group of cells that fired whenever a monkey prepared to act on a stimulus as well as when it watched another monkey act on the stimulus (Winerman, 2005). For example, the monkeys showed a similar pattern of activation when they were performing a simple motor action like grasping a peanut and when they watched another monkey perform the same action (Winerman, 2005). In other words, monkey see, monkey fire -- monkey do, monkey fire. This grouping of cells was called "mirror neurons." The inherent implications of these findings led both researchers and the media to speculate about the potentials for mirror neurons to serve as the basis for many psychological phenomenons. It was not long before researchers began to apply these initial animal findings to humans and uniquely human behaviors such as empathy and language. Were mirror neurons behind our ability to use and learn language? Could mirror neurons help to explain our social connectedness and our ability to understand others?
Making the Leap from Monkeys to Humans
After the initial identification in monkeys, researchers were eager to look for the same system in humans (Winerman, 2005). However, neuroscientists could not use the same single-unit recording that had been used with the sample of monkeys. Rizzolatti and Fadiga examined human hand-muscle twitching suing motor-evoked potentials (Winerman, 2005). These are signals that a muscle is ready to move. The researchers found that the potentials from watching an experimenter grasp and object matched the potentials that were recorded when the participants actually grasped the object themselves. After this initial study, the work on humans has used both fMRI and EEG methodologies. Other...