Free Inventing Iron Man by E. Paul Zehr Page A

intended as you will read), Alexander Monroe (1697–1762) showed that cutting a nerve did not reveal a gushing or outflowing from the nerve. This would have to have occurred if the older ideas of Galen were correct, so Monroe’s experiment proved this wrong. Monroe thought maybe electricity might be involved instead.

    Figure 3.4. The human brain showing different areas of specialization in the cerebral cortex and the cerebellum. Modified from Mysid’s adaptation of the 1918 edition of
Gray’s Anatomy
.
    This idea was met head on—with lots of controversy about “animal electricity”—by two very important Italian physiologists, Luigi Galvani (1737–98, from whose name we get galvanic current and the word “galvanize”) and Alessandro Volta (1745–1825, from whose name we get volts as a measure of electrical amplitude). Galvani showed that a frog leg could twitch even (shortly) after death if the nerves going to the leg muscles were electrically stimulated. The controversy arose because Galvani thought this electrical stimulation used electricity within the frog’s leg (e.g., animal electricity), whereas Volta thought that the frog’s leg was merely a conductor of electricity. So, the combined research of the two men was the first real description of the electrical nature of the nervous system. However (this bit is really important, so pay attention please), when the brains of different animals were stimulated with electricity, not much actually happened. This suggested that maybe the brain didn’t do anything specific and related to the control of movement.
    In fact, Charlotte Taylor and Charles Gross have described how, up until the eighteenth century, the outer surface of the brain (known as the cortex) was actually considered to be a useless “rind.” By the way, this is actually what the root word “cortex” means in Latin. Some scientists correctly disagreed. Thomas Willis (1621–75), a professor at Oxford, and Francois Pourfour du Petit (1664–1741), a surgeon in the French army, both thought the cortex had an important role in movement control. In particular, from observing lesions in injured soldiers and from parallel experiments in dogs, du Petit noted that the outer surface of the brain was indeed very important for movement. These observations from hundreds of years ago helped show that the brain and nervous system were electrical in nature and that there were specialized parts of the brain, including those related to movement.
    Clear evidence of specific functions in different parts of the brain had to wait until the excellent work of Paul Broca (1824–80). In 1861 he wrote about several patients who had difficulties in speaking. They all had damage to the left frontal lobes. This showed clearly that certain functions (in this case, speech) could be largely controlled and affected by very specific parts of the brain. You can roughly locate this part of your own brain by running your hand over the corners of your forehead as your skull moves back toward your ear. Anyway, it would take a bit more creative work after Broca’s research to convince people that parts of the brain participated in movement control.
    It is often said that the human brain is the most complex organ. Measuring activity in such a complex organ is not as simple as you might imagine. Remember, there are 101 billion neurons to listen in on. And they have to communicate together in useful patterns in order to produce all the behaviors we are capable of. Technology has often been a limitation for this kind of measurement and only small numbers of neurons have been recorded. In 2007, MIT neuroscientists Timothy Buschman and Earl Miller conducted a study aimed at looking at attentional focus in monkeys. They recorded from up to five hundred neurons simultaneously in three different brain regions during different tasks of focusing on targets. This represented a