Describe the meaning of Electrical Stimulation

Brain stimulation has been used to map connections in the brain and to elicit changes in behaviour. Much of the pioneering work on mapping out the primary somatosensory and motor cortex was done by neurosurgeon Wilder Penfield in 1958. His participants were his patients, many of whom required surgery for life threatening conditions such as removal of brain tumours or blood clots. He asked them whether, in the course of surgery, they would mind if he applied a mild stimulating electrode to the surface of their brains. Partly thanks to the brain's lack of pain receptors and resultant insensitivity to pain, brain surgery is sometimes conducted with the patient awake, so Penfield could talk to his patients as he stimulated different parts of their exposed brains. Using this technique, Penfield was the first researcher to discover the amazing topographic representation of body areas in the primary motor and somatosensory cortex.