The nervous system consists of the brain and spinal cord of the central nervous system and the ganglia of the peripheral nervous system. The functional unit of the nervous system is a neuron. An estimated 100 billion neurons reside in the brain, with some neurons making between 10,000 and 100,000 connections with other cells! A distinct class of neurons, mirror neurons discharge both when the individual performs a motor action and when they observe another individual performing the same or similar action. These mirror neurons were discovered by neurophysiologists in the 1990s at the University of Parma, Italy. Using macaque monkeys, these researchers found that neurons in the rostral part of the lower premotor cortex were activated both when the monkey performed goal-directed hand movements (grasping, holding, and tearing) and when the monkey observed specific hand movements performed by the experimenters. (Pellegrino et al., 1992). In the inferior frontal cortex and inferior parietal cortex of a monkey, it is estimated that about 10% of neurons have “mirror” properties. her. For example, neurons responded to the sight and sound of torn paper, even when the associated sound was emitted out of the monkey's sight (Kohler et al., 2002). For these types of studies, specific neurons were recorded using microelectrodes inserted into the dura mater of the monkey's brain. Obviously, performing similar experiments on humans is not really possible and so most of the evidence for the existence of human mirror neurons is indirect. However, using functional magnetic resonance imaging (fMRI), researchers have...... middle of article ....... Many scientists have vehemently opposed mirror neurons, both in their existence and in their role in humans and apes. For example, an Oxford researcher claims that the mirror neuron system is not an evolutionary adaptation for understanding action, but a by-product of social interaction (Heyes, 2009). A neurophilosopher, Patricia Churchland, expresses concern about the role of mirror neuron function. She explains that intentions are much more than recordings from individual neurons. According to her, intentions are at a much more complex level of neural activity (Churchland, 2011). Given the many doubts associated with the mirror neuron system, the importance of mirror neurons should not be overestimated and caution should be exercised. At the same time, mirror neuron research related to empathy, understanding intentions, and autism should not be overlooked..