A History of the Brain
Introduction
In the early Middle Ages, three cells were distinguished in the brain: the cellula phantastica, cellula logistica and cellula memoralis. Each of these cells was determined to have a different function and a different location -- the cellula phantastica was located in the front and was responsible for imagination, the cellula logistica was located in the middle and determined reason, and the cellula memoralis was located in the posterior and was responsible for memory. In later documents these "cells" were renamed ventricles. The existence of nerves was also determined during the Middle Ages. Master Nicolai (ca. 1150-1200) considered nerves subservient members of the brain that carried out the animal spirits to all members, endowing them with sensation and motion.
In the sixteenth century, Leonardo Da Vinci started to examine the relationship between the brain and the olfactory and optical nerves through experimenting with wax injections. He sketched many views of the brain, including the ventricles, and the system of nerves throughout the body. He stated definitively that nerves clearly arise entirely from the medulla, which originates at the base of the brain. Da Vinci localized perception, sensation and memory in the ventricles of the brain, but his conceptions of which ventricle controlled which functions of the brain kept changing over the course of his studies. Harvey furthered the development of the anatomy of the brain in the seventeenth century by identifying contained parts of the brain: the cerebrum, cerebellum, medulla, as well as the veins and nerves of the cerebrum and their parts. He also expounded on the descriptions of the aura and pia mater, but the understanding of the basic functions of these membranes remained the same.
Questions to consider: Why did people during the Middle Ages think that the brain had three cells? Why did the basic understanding of the brain remain intact throughout the entire period from the Middle Ages through the Renaissance?
A Collection of Quotations from Original Sources and Images of the Brain:
The Middle Ages
Avicenna, 980-1037
"The brain is cold, but its coldness does not modify the heat of the heart and liver. The heart is dry or nearly so, yet its dryness does not alter the moisture of the brain and liver. The brain [is also not] absolutely and entirely cold. The heart is dry compared with the other two; and the brain is cold compared with the other two."
There are five groups of interior faculties: the composite, the imagination, the apprehensive or instinct, the retentive or memory, and the ratiocinative. The chief seat of the activities of these [first two] faculties is the anterior part of the brain. The seat of [cogitative faculty] is in the mid-portion of the brain. The seat of [retentive faculty or memory] is in the posterior region of the brain.
Master Nicholas, ca. 1150-1200
"The brain, being the most important of the animal members is as follows: Some members are animal, others spiritual, others nutritive, other generative. The animal members are the brain, pie mater, and the like. They are situated above the epiglottis..."
"The brain... is, according to some, of hot complexion; according to others, cold; according to others, moist; in substance,- subtle, thin, and soft; in color, white; in constitution, hollow and spongy; in form, oblong with a degree of rotundity. It is covered by the scalp and the skull, and is enclosed in two membranes."
"On account of the three divisions of the brain the ancient philosophers called it the temple of the spirit, for the ancients had three chambers in their temples, first the vestibulum, then the consistorium, finally the apotheca. In the first the declarations were made in law-cases; in the second the statements were sifted; in the third fmal sentence was laid down. The ancients said that the same processes occur in the temple of the spirit, that is, the brain. First we gather ideas into the cellula phantastica, in the second cell we think them over, in the third we lay down our thoughts; that is, we commit to memory."
The Renaissance
Jacopo Berengario Da Carpi, ca. 1460-1530
CONCERNING THE DURA MATER
" When the cranium is elevated, you will see the aura mater, also called meninge. This is a thick, tendinous and strong panniculus, and is also porous, so that the vapors may escape from the brain. Its form is flat, extended in circular form, embracing all the medulla within itself together with the pie mater of the brain. The aura mater extends from prow to stern doubled in its length and (penetrates) in the direction of the sagittal commissure for a depth of two inches within the substance of the brain, dividing the right part from the left."
CONCERNING THE PIA MATER
" In my judgment it is in these very small branches of the arteries dispersed everywhere in the pie mater that the blood or vital spirit is rendered subtle and prepared so that in the substance of the brain and in its ventricles it may be made into animal spirit..."
" In the walls of the ventricles also there is some portion of the pie mater that carries blood and spirit, blood to nourish the parts nearby to it, spirit for the operations of the soul..."
" Its innate complexion is cold and dry."
CONCERNING THE MEDULLA OF THE BRAIN
" Its size exceeds that of the brain in other animals both on account of its abundance of animal spirits as well as on account of the fact that by its cold and humid complexion (in accordance with reason) it tempers these spirits, which come very hot, from the heart."
" If you should cut an onion through the middle, vou could see and enumerate all the coats or skins which circularly clothe the center of this onion. Likewise if you should cut the human head through the middle, you would first cut the hair, then the scalp, the muscular flesh (galea aponeurotica) and the pericranium, then the cranium and, in the interior, the aura mater, the pia mater and the brain, then again the pia, the aura mater, the rete mirabile and their foundation, the bone."
Pre-Vesalian Anatomists
"The neck sustains the head, in which is contained the brain, the most excellent of the members and the nearest to the sky. Hence the intellect quite clearly holds the highest position as does the human reason, which God the Author and Founder of the world made as close as possible to Himself through his Son." --Alexander Achillinus, 1520.
"The brain is large, divided into anterior and posterior parts. The front part is divided into right and left; the division is apparent in the substance of the brain and in the ventricles." -- Alexander Achillinus, 1520.
"The brain is the origin of all these faculties [the senses], although it may occasionally cause some people to be amazed that sensation and ratiocination arise from a member that is insensitive (for the brain itself is completely without sensation). However, when I say that all of these faculties arise from the brain, we must understand that they arise from the animal spirits which are elaborated in the brain." --Andres de Laguna, 1535
Leonardo da Vinci, 1492-1519
"The entire body has its origin from the heart insofar as the first creation is concerned. Therefore the blood, the veins and the nerves do likewise although these nerves are clearly seen to arise entirely from the medulla nuncha, remote from the heart, and that substance of the medulla is the same as that of the brain from which it is derived."
"Mental matters which have not passed through the sense (sensus communis) are vain, and they give birth to no other truth than what is harmful. And because such discourses spring from poverty of intellect, their authors are always poor and, if they were born rich, they will die poor in their old age."
"The lateral ventricles carry the word imprensiva, the perceptual centre. The third ventricle is labeled sensus communicus or general centre for the special senses, and the fourth ventricle, memoria."
William Harvey, 1653
"Here there is the hair instead of fat and flesh, for the brain which is cold and very humid and largest in man requires the greatest safeguard; for a humid thing is easily terminable; therefore it can endure external injuries only by reason of so many safeguards."
"And so the aura mater is similar to the pleura, the peritoneum, the periosteum; it lies in the middle between the pie mater and the cranium. It is as much softer than the cranium as it is thicker than the pie mater; it is harder, thicker, denser than all the other membranes. Wherefore some believe that it is the organ in the body for all the others and truly the mother of them all"
"The temperament of the brain is cold and humid and soft; cold that it may temper spirits from the heart; lest the heart be inflamed and swiftly lose its power because in the insane the brain has become hot."
"Its substance is very white, very pure; it is very soft in children in whom the reason is imperfect; its often fluid in the embryo, soft and sticky like mild and tranquil spirits, it is not easily dispersed."
Conclusion