History of neuroscience
During the second half of the first millennium BC, the Ancient Greeks developed differing views on the function of the brain. However, due to the fact that Hippocratic doctors did not practice dissection, because the human body was considered sacred, Greek views of brain function were generally uninformed by anatomical study. It is said that it was the Pythagorean Alcmaeon of Croton (6th and 5th centuries BC) who first considered the brain to be the place where the mind was located. According to ancient authorities, "he believed the seat of sensations is in the brain. This contains the governing faculty. All the senses are connected in some way with the brain; consequently they are incapable of action if the brain is disturbed...the power of the brain to synthesize sensations makes it also the seat of thought: The storing up of perceptions gives memory and belief and when these are stabilized you get knowledge." In the 4th century BC Hippocrates, believed the brain to be the seat of intelligence (based, among others before him, on Alcmaeon's work). During the 4th century BC Aristotle thought that, while the heart was the seat of intelligence, the brain was a cooling mechanism for the blood. He reasoned that humans are more rational than the beasts because, among other reasons, they have a larger brain to cool their hot-bloodedness.
Mesencephalic locomotor region
The MLR was first described by Shik and colleagues in 1966 when they observed that electrical stimulation of a region of the midbrain in decerebrate cats produced walking and running behavior on a treadmill. Twenty-eight years later, Masdeu and colleagues described the presence of a MLR in humans. It is now widely acknowledged that, along with other motor control centers of the brain, the MLR plays an active role in initiating and modulating the spinal neural circuitry to control posture and gait. Anatomically, as the name suggests, the MLR is located in the mesencephalon (or midbrain), ventral to the inferior colliculus and near the cuneiform nucleus. Although identifying the exact anatomical substrates of the MLR has been subject to considerable debate, the pedunculopontine nucleus (PPN), lateral cuneiform nucleus, and midbrain extrapyramidal area are thought to form the neuroanatomical basis of the MLR. Nuclei within the MLR receive inputs from the substantia nigra of the basal ganglia and neural centers within the limbic system. Projections from the MLR descend via the medullary and pontine reticulospinal tracts to act on spinal motor neurons supplying the trunk and proximal limb flexors and extensors.