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
Henneman's size principle in this experiment. Experiments were done on 1- to 7-day-old Wistar rats and 20- to 30-day-old Wistar rats as well. The 1- to 7-day-old Wistar rats were selected because early after birth, the rats show an increase in cell size. In 20- to 30-day-old Wistar rats, the physiological and anatomical features of oculomotor nucleus motor neurons remain unchanged. Rat oculomotor nucleus motor neurons were intracellularly labelled and tested using electrophysical properties. The size principle applies to the recruitment order in neonatal motor neurons and also in the adult oculomotor nucleus. The increase in size of motor neurons led to a