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A Brief Neuroscience History About the Brain/Mind Information compiled by Diana Linden from: Bear, Connors, Paradiso. Neuroscience, Exploring the Brain, Williams & Wilkins, 1996 C.G. Gross. Brain, Vision, Memory, Tales in the History of Neuroscience, Massachusetts Institute of Technology Press, 1998 Neuroscience 450 BC –
1700 AD Alcmaeon (~450 BC) believed that the brain was the site of
sensation and cognition.
He probably was the first to use anatomic dissection to learn more
about the human body. One of his
observations (based on dissection of the brain) led him to the idea
that the optic nerves were “light-bearing paths” to the brain. He also thought that the eye
contained light (which was a view held by many neuroscientists until the
middle of the 18th century). Democritis (~425 BC) was a Greek
philosopher-scientist. He
“Thought that everything in the universe is made up of atoms of
different sizes and shapes.
The psyche (soul, mind, vital principle) is made up of the
lightest, most spherical, and fastest-moving atoms. Also that the psychic atoms
mingled among other atoms throughout the body, but they are especially
numerous in the brain.” Empedocles (~445 BC) was a Greek philosopher-scientist who thought that blood was the medium of thought, and that the degree of intelligence depended on the composition of the blood. Therefore, the heart was also the seat of mental disorder. The prevailing theory at the time (until around 1600
AD) was that the heart received and integrated sensations and that it was
the intellectual center of the body (in China, Mesopotamia, Babylonia,
India). Hippocratic doctors: (460-379 BC) believed that the brain was the source of phlegm. They had little knowledge of anatomy, as they did not practice dissection. However, rejected supernatural causes of disease and sought natural explanations through observations and by keeping records of extended case studies. “It ought to be generally known that the source of our pleasure, merriment, laughter, and amusement, as of our grief, pain, anxiety, and tears, is none other than the brain. It is specifically the organ which enables us to think, see, and hear, and to distinguish the ugly and the beautiful, the bad and the good, pleasant and unpleasant. It is the brain too which is the seat of madness and delirium, of the fears and frights which assail us, often by night, but sometimes even by day; it is there where lies the cause of insomnia and sleep-walking, of thoughts that will not come, forgotten duties, and eccentricities.” (p. 13, Gross) Neither the diaphragm nor the heart had any mental functions. A quote from a doctor
around that time shows that although they believed the brain was
important, they knew little of the mechanisms of brain
function. “Should [the] routes for the passage of
phlegm from the brain be blocked, the discharge enters the blood vessels .
. . this causes aphonia, [lack of speech] choking, foaming at the mouth,
clenching of the teeth and convulsive movements of the hands; the eyes are
fixed, the patient becomes unconscious and in some cases, passes a
stool. All these symptoms are
produced when cold phlegm is discharged into the blood which is warm, so
chilling the blood and obstructing its flow.” (p. 13, Gross) Aristotle:
(384-322 BC) who was an important influence on his peers, and
who also studied comparative anatomy believed that the brain was a cooling
organ. The heart was the seat
of sensation and thought.
“And of course the brain is not responsible for any of the
sensations at all. The
correct view {is} that the seat and source of sensation is the region of
the heart. . . . the motions
of pleasure and pain, and generally all sensation plainly have their
source in the heart.” Galen (130-199 BC) was one of the first to produce an accurate and detailed account of the anatomy of the brain. Galen probably had more experience with the human body, its reactions, and anatomy than many others of his era. He had extensive clinical experience treating gladiators at the gladiator school in Pergamon). He discovered three ventricles (large fluid-filled spaces) within the brain and hypothesized that they were the sites of storage of psychic pneuma (animal spirits). The soul and higher cognitive functions were located in the solid portions of the brain. The prevailing theory at this time was that the body functioned according to a balance of four vital fluids – humors. Sensations were received and movements initiated by the movement of humors accounted for sensation and initiation of movements. The humors were thought to move to or from the three brain ventricles via the nerves, which were believed to be hollow tubes, like the blood vessels. Leonardo da Vinci (1452-1519) was one of the Renaissance artists who
started making accurate illustrations of the human body, beneath the skin
(surface musculature)
“Painters bought their pigments at the same shops where doctors
bought their medicines, and human dissections were usually open to the
public.”(p. 95, Gross) In his
sketches he also "drew
three cerebral ventricles according to the medieval theory of the
ventricular localization of psychological function.” Around this time French inventors were experimenting
making hydraulically controlled machines. the brain functioned like a
machine. Fluid forced out of
the ventricles through the nerves might literally “pump you up” and cause
the movement of the limbs. Descartes (1596-1650) supported the hydraulic fluid movement
theory to explain brain function and behavior in animals. However,
he concluded that this theory could not account for some characteristics
of humans, like intellect and a God-given soul. rain mechanisms controlled
behavior only to the extent that this behavior resembles that of the
beasts. Uniquely human
capabilities existed outside the brain - in the “mind”. Andreas Vesalius of Padua 1514-1564 was one of
“the greatest of the Renaissance anatomists”. He did not believe the ventricular
doctrine of brain function.
In his dissections he found that many animals (and all
mammals), have the same ventricles as humans, but he also reasoned that
they do not have a soul. the
importance of the ventricles in higher brain functions, he drew and
labeled the ventricular structures in much more detail and with much more
care than he depicted the cerebral cortex. Vesalius believed that the
function of the convolutions of the cerebral cortex was “to allow the
blood vessels to bring nutriment to the deeper parts of the brain.” Shakespeare’s Love’s Labours Lost: “A foolish extravagant spirit,
full of forms, figures, shapes, objects, ideas, apprehensions, motions,
revolutions. They are begat
in the ventricle of memory, nourished in
the womb of pia mater.” Archiangelo Piccolomini (1526-1586) was a professor of anatomy in Rome who
succeeded in separating the cerebral cortex from the underlying white
matter. The
cerebral cortex was considered to be an unimportant rind (or protective
covering). Hobbes 1588-1679
Marcello Malpighi (1628-1694) observed the
microscopic anatomy of the cerebral cortex. His observations
suggested that the cerebral cortex was made up of “a mass of very
minute glands” with attached fibers. These are found in “the cerebral
gyri, which are like tiny intestines”.
Frederik Ruysch (1628-1731) believed that the
function of the convolutions of the cerebral cortex was “. . . to make the
cerebral [blood] vessels safe by guiding them through these tortuosities
and so protect them against danger of rupture from violent movements,
especially during full moon when the brain swells
in the skull.” Thomas Willis (1621-1675) was a professor at
Oxford and the author of the first monograph on brain
anatomy and physiology.
He believed that sensory and motor function came into the striatum,
where common sense was located.
Then these sensations were elaborated into perception and
imagination and finally stored as memories in the cerebral cortex. “As often as a sensible
impressions, such as a visual stimulus, arrives from the periphery it
turns inwards like an undulation of water and is transferred to the
corpora striata where the sensation received from outside becomes a
perception of internal sense.
If, however, this impression is carried further and penetrates the
corpus callosum, imagination takes the place of sensation. If after this the same undulation
of the spirits strikes against the cortex, as it were the outermost banks,
it imprints there a picture or character of the object which, when it is
later reflected from there revives the memory of the same thing.” Through his investigations he found (the convolutions
of the cerebral cortex are called gyri), “Those gyri are fewer in
quadrupeds, and in such as the cat, they are found to have a particular
shape and arrangement so that this beast considers or recalls scarcely
anything except what the instincts and demands of nature suggest. In the smaller quadrupeds, and
also in birds and fish, the surface of the brain in flat . . . Hence it is
that animals of this sort understand or learn few things.” Francois Pourfour du Petit (1644-1741) was a
French army surgeon. He found, through his observations of wounded
soldiers and animal experimentation, that the cerebral cortex has
contralateral motor function.
His research was probably ignored largely because of the anticortex
ideology of the time. Emanuel Swedenborg (born 1688) wrote “I have pursued this [brain]
anatomy solely for the purpose of discovering the soul. If I shall have furnished anything
of use to the anatomic or medical world it will be gratifying, but still
more so if I shall have thrown any light upon the discovery of the
soul.” At the end of 17th century interest in
the importance of the cerebral cortex waned, and the theories of the
cortex as a glandular, vascular, or protective rind returned to their
original dominance. Middle of 18th century Albrecht von Haller (1708-1777) was among other
things a botanist, poet, novelist, politician, and professor in
Germany. Using live animals,
von Haller determined that prodding of the cerebral cortex produced no
sensations or responses.
However prodding different regions of the brain “produced
expressions of pain, attempts of the animal to escape, or
convulsions.” (p. 49, Gross)
Although his gruesome results produced information more in accord our
modern view of the brain function, he further states that the cerebral
cortex consisted of mere vessels. It's function was to house blood
vessels. A common view at that time was that the cerebral
cortex was considered an insensitive rind with no sensory, motor, or
higher functions. . Franz Joseph Gall (1758 – 1828) believed that different psychological functions were localized in different regions of the cerebral cortex. Co-founder of phrenology (study of personality based on bumps on the head)! brain was an elaborately wired machine for producing behavior, thought, and emotion, and that the cerebral cortex was a set of organs with different functions.” It was postulated that about 35 affective and intellectual faculties could be defined. Three assumptions of their theory were that the affective and intellectual faculties (a) were localized in specific organs of the cerebral cortex; (b) the development or prominence of these faculties was a function of their activity, and the amount of activity would be reflected in the size of the cortical organ; and (c) the size of each cortical organ was indicated by the prominence of the overlying skull, that is, in cranial bumps.” (p. 52, Gross) We've come a long way since the 1800's. |