Motor Neuron Disease (MND) is a serious and incurable neurologic disease which is characterized by progressive degeneration of motor neurons. It may occur after the injury of upper and lower motor neurons.
Neurons have different shapes depending on their functions. Interneurons carry information between motor and sensory neurons. Sensory neurons carry information to the central nervous system. Motoneurons carry signals from the central nervous system to the muscles, skin, and glands and pyramidal neurons are involved with motor control and cognitive ability. http://health.howstuffworks.com/human-body/systems/nervous-system/brain-pictures24.htm
"Brains are gorgeous at the right magnification", says Mark Miller. His images are quite impressive, particularly since the neurons connecting in the brain resemble the large-scale structure of the universe.