Adolescent is defined as a "person 13 to 18 years of age".[1] The term teenager is approximately equivalent; a person whose age is a number ending in '-teen' in the English language. The developmental stage is called adolescence.
During this period of life, children go through the stages of puberty. Most cultures regard people to have become adults at various ages of the later adolescent years.
Magnetic resonance imaging[2] and functional magnetic resonance imaging[3] has investigated the normal development of the brain.