Simulation theory proposes that when an individual observes emotional facial expressions, there is an automatic activation of neural circuits. This neuronal activation allows individuals to mentally reproduce the emotion and, consequently, to recognize it. In other words, an internal mirroring process is generated within the individual, facilitating the recognition of others’ emotions and the understanding of their affective states. In this theoretical framework, the ability to recognize emotions on others’ faces, commonly known as Facial Emotion Recognition (FER), represents a fundamental aspect of social sphere, supporting empathy and facilitating interaction and communication. In this context, the mu rhythm plays a pivotal role; it is a sensorimotor oscillation considered an indicator of Mirror Neuron System (MNS) activity during facial emotion recognition.