The substantia nigra is my most favorite part of the brain. Substantia Nigra (Pronounced roughly like Sub-stan-chia N-i-grah, the I in nigra like "you and I") means black substance in latin and was named for its darkly colored melanin pigmented neurons. The substantia nigra is a deep brain structure located in the cranial (superior) regions of the mesencephalon (or midbrain), a part of the brain stem. The substantia nigra plays a critical role as a part of the basal ganglia/nuclei. The SN is essential for performing voluntary movements. The plan of any movement we perform has been run through the SN first in a series of high frequency action potentials and relayed eventually on to cerebral cortex where our conciousness lives. The substantia nigra is the indirect facilitator of movement. For a movement to be carried out after the plan for the movement has been "approved" by the basal ganglia, the electrical message travels from the precentral gyrus down to a target neuromuscular junction through a relay of other structures, but that is another story... Obviously this has everything to do with transformers! :D