Many studies have emphasized simulation theory as a core concept for the mirror neurons that are found in the ventral premotor area (F5) and inferior parietal cortex (PF) of the macaque. Imitation, social cognition, empathy and language are linked to mirror neurons. However, function of mirror neurons in the macaque is still missing, because such cognitive functions are limited or lacking in these monkeys. It is important to discuss these neurons in the aspect of motor function. I would suggest that mirror neurons in area PF might have a roll of monitoring of self generated action. This idea may provide neural correlate of self other distinction.