By some reports, the word samurai first appeared in the 12th century. For a long time, the samurai provided the main military force used against emishi and other clans. In the 1100s, two powerful clans served the emperor of Japan: the Taira clan, and the Minamoto clan. These two families became bitter rivals, and in 1192, Minamoto Yoritomo led his clan to victory over the Taira.
EEG measures brain activity and must demonstrate regular wave patterns to be considered valid. Therefore, by this rule the onset of life would be the time when fetal brain activity begins to exhibit regular wave patterns, which occurs fairly consistently around week 25. Previous to that time, the EEG only shows small bursts of activity without sustained firing of neurons.
Brain development: Frontal lobe. The frontal lobe of the brain (located behind the forehead) handles all thought and voluntary behavior such as walking, speech, and problem solving, and some aspects of emotion. Development in this area really takes off between six and 12 months, when your baby becomes more mobile and verbal.