I've used various versions of the Stick and I agree completely that it seems overpriced when you consider what it *is*, but the darn thing is good at what it *does*, and you'll quickly get over the cost.
In vertebrate species it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body.
(B) The peripheral nervous system includes all of the motor and sensory tissue in the body except the brain and spinal cord. The main peripheral system components are the 12 pairs of cranial nerves and the spinal nerves. Cranial nerves control some sense recognition and motions of the head and neck. The facial nerve that controls facial motion and the optic nerve that controls vision are examples of cranial nerves.