Download Contribution to the Development of Neuroscience in Medical Schools

Bulletin of the Transilvania University of Braşov • Vol. 6 (51) - 2009
Series 6: Medical Sciences
Supplement – Proceeding of The IVth Balkan Congress of History of Medicine
THE IMPORTANCE OF STUDYING GREEK
PHILOSOPHERS AND PHYSICIANS (5TH –
3RD CENTURY B.C.): CONTRIBUTION TO
THE DEVELOPMENT OF NEUROSCIENCE
IN MEDICAL SCHOOLS
1
D. DIACONESCU , S. TOMA1,
R-S DIACONESCU1
Abstract:
The nature of psychic life, the anatomical seat of cognitive, motor and
sensory functions, and the origin of neurological diseases were broadly
debated by ancient Greek scientists since the earliest times. Within a few
centuries, speculation of philosophers and physicians laid to foundations of
modern experimental and clinical neuroscience. In this review we shall
present the most important Greek philosophers and physicians living between
the 5th and the 3rd century before Christ (B.C.) and examine some of their
leading theories concerning the mechanisms of cognitive activity, the nature
of perception and voluntary movement, and the causes of neurological and
psychiatric disorders
.
Key words: History of neuroscience; Presocratic philosophers;
Alexandrian medicine; Hippocratic medicine.
Introduction
Since the earliest times ancient Greek
scientists debated the nature of psychic life,
the anatomical seat of motor, sensory and
cognitive functions, and the basis of some
neurological and psychiatric diseases.
The aim of this study was to present the
theories of the most important ancient
Greek philosophers and physicians (5th-3rd
century B.C.).
Content
The origin of thinking activity was
explained by Greek philosophers and
physicians based on two theories. The
encephalocentrism considered the brain as
1
Transilvania University of Brasov
the seat of human consciousness, sensation
and knowledge, all these faculties being
attributed by the cardiocentrism to the
heart. Both theories generated controversy
within the scientific community [4].
a. Philosophers
Hippon of Samos (4th century BC)
localized the main part of the soul to the
head, particularly to the brain. Anaxagoras
of Clazomenae (500–428 BC) and
Diogenes of Apollonia (ca. 460 BC)
believed that all sensations had connection
to the brain [4].
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Bulletin of the Transilvania University of Braşov • Vol. 6 (51) - 2009 • Series VI
Empedocles of Acragas (490–430 BC)
thought that “the blood around the heart is
men’s thought” [5]. Thus, humans think
with the blood and the level of intelligence
depends on blood’s composition. That is
why he considered the heart also as the
seat of mental disorder [19].
In the opinion of Empedocles, sensation is
a purely physical process, depending on pores
and affluences. Affluences enter continually
in another body through pores and sensation is
a matter of symmetry of pores [5].
Aristotle also identified three possible
nerves - “poroi” (ducts) – two of them
leading to the cerebellum and one to the
brain [1]. These ducts might refer to the
optic nerve and tract, and to trigeminal and
oculomotor nerves [3]. He also described a
cavity in the brain, probably the ventricular
system, and made the observation that man
has the largest brain in proportion of his
size. He also referred to “liquidity about
the brain”, probably the cerebrospinal
fluid. Aristotle described the spinal cord as
an extension of the brain and the similar
constitution for both structures [1]. But
Aristotle’s theories about brain function
were rather dissapointing. In his view,
brain had no sensory properties and was
insensible when touched. He concluded that
the brain was a cooling organ, after he
noticed a lot of blood vessels on the surface
of the brain, therefore having no intellectual
meaning. Aristotle also considered the brain
as the sleep generator [3].
Fig.1. Empedocle – source Wikipedia
Aristotle (384 BC – 322 BC) was
probably the first anatomist in the modern
sense of this term [11]. According to
Aristotle, the soul is defined as the the
form of a living body [18].
Aristotle had interesting contributions
to brain anatomy. He observed that the
brain was placed in the front part of the
head and was surrounded by the meninges,
two membranes containing blood vessels.
The external membrane was the thickest
and located next to the bone of the skull;
the more delicat internal membrane was
localized around the brain itself.
For the first time an important
anatomical distinction between cerebrum
(enkephalos, brain) and cerebellum
(parenkephalis, para-brain) was made by
Aristotle. The para-brain was positioned
beyond the brain, and its shape and tissues
were different from those of the brain.
Fig.2. Aristotle – source
www.wicknet.org/.../gallery_of_the_greats.htm
b. Physicians
The sensory and cognitive significance
of the brain was probably first recognized
by Alcmaeon of Croton (500 BC) [15]. He
asserted that “all the senses are connected
with the brain” through channel-like
structures called “poroi”, two of them, no
DIACONESCU et al.: The importance of studying Greek philosophers and physicians (5th – 3rd 49
century B.C.): contribution to the development of neuroscience in medical schools
doubt the optic nerves, joining the eyes to
the brain. Alcmaeon claimed that the brain
was the seat of consciousness and
sensation because he recognized that all
senses “are compromised if the brain is
moved and changes its place” [5].
He distinguished sensation from
understanding: “man differs from the other
animals in that he alone has understanding,
wheras, they have sensation but do not
understand” [4].
Based on anatomical evidence, he
proposed that the brain was essential for
perception [6, 7] and “the seat, in which
the highest, principal power of the soul is
located” [5].
Alcmaeon was wrong saying that sleep
occurs when blood vessels in the brain are
filled and that waking is caused by the
emptying of these vessels [16].
sacred than other disease, but has a natural
cause, and its supposed divine origin is due
to men’s inexperience and to their wonder
at its peculiar character”. In the same
treatise, the brain was considered the seat
of judgement, emotions and aesthetic
activity [12]. Thus thinking activity, moral
consciousness, perceptive elaboration and
control of body’s movement, were
functions all localized to the brain.
Hippocrates explained mental insanity
as a process of brain corruption induced by
bile, one of the four humours.
In a case report about sudden loss of
speech and paralysis of the right hand, the
term “spasm” is used [13].
It was stated that “an incised wound in
one temple produces a spasm in the
opposite side of the body” and that loss of
speech occurred with “paralysis of the
tongue or of the arm and the right side of
the body” [2].
Hippocrates was also one of the most
prominent ancient greek physician who
practiced trepanation [17]
Fig.3. Alcmeon – source philosophers.endlessgreece.com/alcmaeon.php
In the fourth century BC, Hippocrates
(ca. 460 BC – ca. 370 BC), the “Father of
Medicine”, started a new way of looking at
illness. The main theory stated that disease
is the result of an imbalance of body
constituents or humors and that disease has
nothing to do with demons [10].
For Hippocrates the human brain is
cleft into two symmetrical halves by a
vertical membrane and is also the seat of
human intellect and the cause of
neurologcal disorders. In De morbo sacro,
epilepsy, called in antiquity “the sacred
disease”, is not “any more divine or more
Fig.4. Hippocrates – source
http://commons.wikimedia.org/wiki
Diocles of Carystus (ca. 375–300 BC)
stated that the right half of the brain
provided
sensation and the
left
intelligence, and that the heart is the centre
for hearing and understanding. In his
opinion, madness was “boiling of the
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Bulletin of the Transilvania University of Braşov • Vol. 6 (51) - 2009 • Series VI
blood in the heart”, lethargy was “a
chilling of the psychic pneuma about the
heart and the brain and a freezing of the
blood dwelling in the heart”, and
melancholy was considered as a disorder
arising “from thickening of black bile
around the heart” [8].
Erasistratus of Chios (ca. 304 – ca. 250
BC) founded, together with Herophilus, a
school of anatomy in Alexandria, where
the two performed human dissections on
criminals [21].
Erasistratus described a system of
humors consisting of nervous spirit carried by nerves -, animal spirit - carried
by arteries -, and blood - carried by veins.
Erasistratus considered that atoms are the
essential body element. Atoms were
activated by pneuma (external air) that
circulated through the nerves. He thought
that the inspired air is transformed into
“vital spirit” and transported to the brain’s
ventricles, where it becomes “animal
spirit”. The animal spirit filled the empty
nerves and let them control the muscle
movement [21].
According to Erasistratus, the dura
mater had the greatest significance, being
considered the center of sensitive, motor,
and cognitive functions. Therefore,
psychiatric and neurological disorders
were thought to depend on pathological
changes of this membrane. He considered
that lethargy “arises from an affection of
the psychic faculty in the meninx, which is
precisely where lethargy occurs”. Delirium
was “a disorder of the activity of the
meninx” [9].
Erasistratus is one of the first who
described the cerebrum and cerebellum.
Initially, he asserted that nerves also
originate from the meninges. Later, he
recognizes that nerves originate from
brain. He also established a relationship
between the the number and complexity of
the human brain convolutions and
intelligence [8].
Fig.5. Erasistratus of Chios – source
http://www.encyclopedia.com/
Herophilus of Chalcedon (335-280
BC), the “Father of Anatomy”, is also
considered the founder of human anatomy
as a distinct branch of medicine [14].
Fig.5. Erasistratus of Chios – source
womenshealth.medinfo.ufl.edu/.../slide5.html
He made a series of accurate
descriptions of neuroanatomical structures.
He also made a clear distinction of the
brain ventricles, identifying that they are in
reciprocal communication and therefore
allow passage of the psychic pneuma.
He described precisely the cerebellar
ventricle, the fourth ventricle or the
posterior ventricle. He also described and
nominated some structures visible on the
floor of this cavity, such as the calamus
DIACONESCU et al.: The importance of studying Greek philosophers and physicians (5th – 3rd 51
century B.C.): contribution to the development of neuroscience in medical schools
scriptorius, the posterior median sulcus
and the colliculus facialis. He accepted
Aristotle’s distinction between enkephalos
and paraenkephalos, recognizing that they
are separated by a thick membrane –
tentorium cerebelli.
He described a membrane covering the
ventricles of the brain as the “choroid
meninx”. Along with Erasistratus, he was
considered the first anatomist who
identified motor and sensory nerves and
who located their origin correctly in the
brain or in the spine. He described the
optic, oculomotor, trigeminal, motor root
of the trigeminal, facial, acoustic and
hypoglossal nerves [4, 20].
Erasistratus and Herophilus first
identified that cutting nerves causes
paralysis.
References
3. Clarke E. Aristotelian concepts of the
form and function of the brain. Bull
Hist Med All Sci 1963;37:1-14.
4. Crivellato E, Ribatti D. Soul, mind and
brain: Greek philosophy and the birth
of neuroscience. Brain Research
Bulletin 2007;71(1):327-338.
5. Diels H, Kranz W. Die Fragmente der
Vorsokratiker. 12th ed, Berlin, 1966.
1. Aristotle, Gotthelf A. Historia
Animalium, vol. I: Books I-X Cambridge Classical Texts and
Commentaries, No. 38, 2002
2. Chadwick J, Mann NW. The Medical
Works of Hippocrates. Blackwell,
London, 1950.
Conclusions
All these theories represent great
achievements transmitted by Greek
philosophers and physicians to later
generations of neuroscientist.
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6. Doty RW. Alkmaion’s discovery that
brain creates mind: A revolution in
human knowledge comparable to that
of Copernicus and of Darwin.
Neuroscience 2007; 147(3):561-568.
7. Doty RW. Alkmaion, ca 500 BC,
discovers that mind is in the brain.
Neuroscience Research 2007; 58
(suppl.1): S243.
8. Garofalo I. Figure della medicina
ellenistica. In: G. Cambiano, L.
Canfora, D. Lanza “Lo spazio
letterario della Grecia antica”, vol. 1.
2, Roma 1993:345-368.
9. Garofalo I. Anonimi Medici, De
Morbis acutis et chroniis. EJ Brill,
Leiden 1997
10. Garrison FH. History of Medicine.
Philadelphia, W.B. Saunders, 1966
11. Gross CG. Aristotle on the brain. The
Neuroscientist 1995;1(4):245-250.
12. Hanson AE. Hippocrates: The “Greek
Miracle” in Medicine. In: Medicine,
Lee T. Pearcy, The Episcopal Academy, Merion, PA 19066, USA, 2006
13. Hippocrates. Of the Epidemics (400
BCE). Section III, case 13. Translated
by F. Adams.
14. Longrigg J. Anatomy in Alexandria in
the third century BC. Brit J Hist Sci
1988; 21: 455-488.
15. Lloyd GER. Alcmaeon and the early
history of dissection. Sudhoffs Arch
1975; 59: 113-147.
16. Lyons AS, Petrucelli RJ. Medicine. An
Illustrated History. New York: Harry
N. Abrams, Inc., 1987:187,192
17. Mission S. Hippocrates, Galen, and the
uses of trepanation in the ancient
classical world. Neurosurg Focus
2007;23(1):E11.
18. Movia G. Aristotele. Anima, Milano:
Rusconi, 1996
19. Phillips ED. Greek Medicine (Aspects
of Greek and Roman Life). London,
Thames and Hudson, 1973.
20. Rowe CJ. Plato: Phaedo (Cambridge
Greek and Latin Classics). Cambridge,
University Press, 1993.
21. Wright JP, Potter P. Psyche and soma:
physicians and metaphysicians on the
mind-body problem from antiquiry to
Enlightenment. Oxford: Clarendon
Press 2000.