Brainstem neuron

The medulla oblongata is the lowest part of the brainstem, the stretch that links the brain to the spinal cord. Its nerve cells are not scattered at random: the medulla holds many nuclei, which are tight clusters of nerve cells, and tracts, which are bundles of fibers. One region of it called the tegmentum holds the inferior olivary nucleus and the nuclei of four cranial nerves, the ninth, the tenth, the eleventh and the twelfth.

Some of those neurons are lower motor neurons, the ones that give the muscle its final command. The signal to move usually sets out from nerve cells in the brain and stops in cells of the brainstem and the spinal cord, and from there it goes out to the muscles of the body: it is a relay race in which the brainstem takes the baton halfway around the track.

And one area of the medulla, the rostral ventrolateral medulla, has a different job: its neurons are excitatory, and they carry information to presympathetic neurons in the spinal cord, the ones that hold blood pressure at its baseline level without any conscious decision.