**1. Introduction**

Previous neurophysiological and brain imaging studies have revealed that neural activity associated with observation of another person's movement was elicited in the motor‐related cortical areas [1–3]. The motor‐related cortical areas that get active during such motion per‐ ception, constitute the mirror neuron system. Characteristically, this system is activated not only when a person performs a goal‐oriented movement by himself/herself, but also when the person observes the same movement performed by others (**Figure 1**) [4]. Action observation automatically creates a similar simulation of movement in the brain of the observer [5, 6]. In other words, action observation induces functional reorganization of the brain, and facilitates

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

motor learning via the mirror neuron system (**Figure 2**) [7, 8]. Thus, observation of another per‐ son's actions and behavior alters the neuronal activity of the observer. This chapter discusses neurophysiological and brain imaging studies of action observation, and their application to human motor learning.

**Figure 1.** Mirror neurons in monkeys [4]. Top indicates the neural activity in area F5 when the monkey grasps food. Bottom indicates the neural activity in are F5 when the monkey observes the human grasping food.

**Figure 2.** Mirror neuron system in humans [7]. Purple areas (PMD and SPL) are involved in reaching movements. Yellow areas (IFG, PMV, IPL and IPS) are involved in transitive distal movements. Blue areas (STS) are involved in observation of upper‐limb movements. Green areas (A) are involved in intransitive movements. Orange areas (B) are involved in tool use. PMD indicates dorsal premotor cortex; SPL, superior parietal lobule; IFG, inferior frontal gyrus; PMV, ventral premotor cortex; IPL, inferior parietal lobule; IPS, intraparietal sulcus; STS, superior temporal sulcus.
