Studying the Brain

1895

MODERN SCIENCE KNOWS HOW WE THINK, SEE, HEAR AND FEEL.

Locating Brain Diseases by Observing the Action of Parts of the Body — Curious Things Brain Experts Have Discovered From Experiments.

Definite knowledge has recently been acquired regarding the anatomy of the human mind. It is now understood, with a fair degree of accuracy, where and how ideas of various kinds originate in different parts of the so called gray matter.

The organ of thought has been divided up into sections, as it were, which are severally responsible for the creation of ideas and images of many classes. Certain areas of brain surface are recognized as controlling vision, hearing, taste, smell and vocal speech, while others govern the muscular mechanism of the body. If you move your big toe, you direct its motion by orders conveyed from a point of the cerebral cortex directly beneath the very middle of the top of the skull.

At the University of Pennsylvania important work in this line of scientific research is being carried on under the direction of Dr. Lightner Witmer. He has a laboratory fitted up with all sorts of queer looking machinery for finding out how long it takes people to think, to see, to hear, to feel, to distinguish colors and other such things. There are models of brains, which one may take apart and put together again as if they were Chinese puzzles.

Most of the knowledge thus obtained has been got by studying the brains of lower animals, chiefly dogs and monkeys. It does not always follow that what is true of a monkey is true of a man, and scientists have been led into a good many errors by assumptions of that kind. Unfortunately it is not practicable to make experiments upon living human brains, save in exceptional eases where surgical operations have to be performed on them. But it is very easy to remove a portion of the skull of a monkey and to observe how the beasts acts when stimulation — electricity is usually employed for the purpose — is applied to one portion or another of the surface.

Acquaintance with the so called motor areas has become so accurate that a disease of a part of the brain can usually be located with exactness by observation of the muscles of the body. An abnormal wiggle of the big toe would lead the physician to look for trouble in the middle of the top of the head. Maybe there would be no cure for it, and then again perhaps something might be done. If it were ascertained that the patient had received a blow there, it might he imagined that a fracture previously unsuspected had occurred, causing pressure on the brain. In that case relief would probably be obtained by trephining.

An interesting instance on record is that of a girl who was suddenly seized with paralysis of one side of the face, accompanied by loss of power of speech. Within three or four days the paralysis passed downward from the arm to the body and finally to the leg on the same side. It was decided by the doctors that the symptoms indicated a brain hemorrhage up the fissure of Rolando and involving the areas corresponding to the arm and leg. The girl died, and a post mortem examination disclosed the fact that this was exactly what had occurred.

The fissure of Rolando runs across the top of the head from side to side and almost from ear to ear. In and about it are located the most important motor areas which govern the muscular movements of the body. The highest point corresponds to the toe. Following the fissure down the side of the head toward the ear comes the leg, next the arm and finally the face. That portion which represents the face is much more highly differentiated — i. e., split up into a great many smaller areas. Thanks to this arrangement, one is able to vary one's countenance with an almost infinite play of expression, every little muscle being under ready control.

Close by and associated with the area representing the face is that of vocal speech. This latter area is so highly differentiated that each letter and numeral seems to possess its own special tract. There is a case on record of a man who forgot the letters B, P, Q, X and Y and the numerals, 6, 7 and 8. In other respects he was all right. But he could not read because the letters mentioned were unknown to him. Of course he could not write either. He was unable to add 2 and 6 because 6 was unknown to him. When he tried to write out the word "six," he could only get as far as the first two letters, inasmuch as "x" was forgotten.

People remember things in different ways, according to the habit of the individual. For example, you ask one man when Columbus discovered America, and he will reply 1492 promptly, having a visual picture of the figures forming that date in his mind. But another person will recall the date not in that manner at all, but by sound. In the latter case it may be the centers of hearing that furnish the memory, but it is more likely to be those of vocal speech. The host spellers are visualists. They see mental pictures of words, spelling them by reading them off as if from a blackboard. Lots of folks have no such pictures at all. Most of them seem to depend chiefly, if not wholly, upon the habit of using the letters and syllables in certain forms of speaking.

The part of the brain belonging to and representing each sense — seeing, hearing or what not — seems to be a complete little brain in itself. A banker of Frankfort lost the use of his visual brain for purposes of memory and was obliged to begin like a child and train his auditory brain. The orator, whose words pour out in an eloquent flood, as it self inspired, possesses centers of vocal speech which are highly developed, constituting in themselves a brain capable of doing its own thinking, as it were. — New York World.