Different tracts of neurons are involved with voluntary and involuntary movements. Involuntary movements are processed largely through a group of brain cells known as extrapyramidal neurons. They connect input from the cerebellum and the inner ear to the brain stem. The first two areas process information about coordination and balance. The brain stem sends this information to motor neurons in the spinal cord, which connect directly to the muscles involved. Thus, information related to involuntary movement does not go through the cortex and generally travels in a relatively simple, closed circuit.