About two decades ago, it was discovered that some neurons in F5 area of ventral premotor cortex of the macaques monkeys discharged not only when the monkeys performed a motor act, but also when they saw the same act being done by another monkey. The accidental discovery of these fascinating neurons, named the Mirror Neurons, urged the scientists to think of presence of such kind of neurons in humans because the same area, the premotor cortex, exists in the human brain. In this article, we review first the basic properties of these neurons in monkeys. We then describe the Mirror Neuron System (MNS) in humans; we also compare the MNS of monkeys with that of humans. The aim of this review is to provide an account of the basic concepts &functionalproperties of the system formed by mirror neurons.

Keywords: Mirror Neurons; Imitation; Action Understanding.