CNS develop? A human embryo consists of three major cell layers known as the ectoderm, mesoderm and endoderm. The CNS develops from a specialised region of the ectoderm called the neural plate. The process through which the neural plate starts to form the nervous system is called neural induction. The neural plate lies along the midline of the embryo. A midline indentation forms and deepens along the neural plate to form a groove known as the neural groove. This groove then closes to form a hollow tube known as the neural tube. All major components of the CNS are then present including the spinal cord and brain stem. What happens to the CNS as we age? The functioning of the nervous system changes from childhood to old age, reaching its peak development at around the age of 30. Different aspects of brain function tend to be affected at different ages. For example, vocabulary and the use of words start to decline at around age 70, while the ability to process information can be maintained until age 80 if no neurological disorders are present. As aging occurs, the overall number of nerve cells starts to decline. A brain generally weighs 56% less at the age of 75 than at the age of 30 due to this decrease in brain cells. Overall brain function is also slowed due to several factors. These include less efficient synapses and the slowing down of the transmission of electrical signals between neurons. Engaging in mental and