Facial expression responsible for controlling the expression differ in each case. Voluntary facial expressions are often socially conditioned and follow a cortical route in the brain. Conversely, involuntary facial expressions are believed to be innate and follow a subcortical route in the brain. Facial recognition is often an emotional experience for the brain and the amygdala is highly involved in the recognition process. The eyes are often viewed as important features of facial expressions. Aspects such as blinking rate can possibly be used to indicate whether a person is nervous or whether he or she is lying. Also, eye contact is considered
Birth defects of diethylstilbestrol also have an increased risk of uterine fibroids, and incompetent cervix in adulthood. Studies of DES daughters have not found a link between "in utero" exposure to DES and autoimmune diseases. In an animal model designed to study environmental estrogens, DES turned out to be an obesogen capable of causing adult weight gain in female mice which had been exposed to DES during neonatal development. The excess weight gain was not apparent at birth or in infancy, but occurred in adulthood. Initially, fewer studies documented risks of prenatal exposure to DES on males (referred to as "DES sons"). In the