TABLE
I. II. III. IV. V.
Introduction General Information & Function Evolution of the Human Brain The Mind Geometrical Consciousness
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ntil about 100 years ago, the only evidence that brain and mind were connected was obtained from “natural experiments”- accidents in which head injuries created aberrations in their victims’ behavior. Dedicated physicians mapped out areas of the cerebral landscape by observing the subjects of such experiments while they were alive-then matching their deficits to the damaged areas of their brains. It was slow work because the scientists had to wait for their subjects to die before they could look at the physiological evidence. As a result, until the early
20th century, all that was known about the physical basis of the mind could have been contained in a single volume. Since then, scientific and technological advances have fueled a neuroscientific revolution. Powerful microscopes made it possible to look in detail at the brain’s intricate anatomy. A growing understanding of electricity allowed the dynamics of the brain to be recognized and then, with the advent of electroencephalography (EEG), to be observed and measured. Finally, the arrival of functional brain imaging
machines allowed scientists to look inside the living brain and see its mechanisms at work. In the last 20 years, positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and, most recently, magnetic encephalography (MEG) have among them produced an ever more detailed map of the brain’s functions.
The human brain is like nothing else.
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s organs go, it is not especially prepossessing - 31b (1.4kg) or so of rounded, corrugated flesh with a consistency somewhere between jelly and cold butter. It doesn’t expand and shrink like the lungs, pump like the heart, or secrete visible material like the bladder. If you sliced off the top of someone’s head and peered inside, you wouldn’t see much happening at all. Given this, it is perhaps not surprising that for centuries the contents of our skulls were regarded as relatively unimportant. When they
mummified their dead, the ancient Egyptians scooped out the brains and threw them away, yet carefully preserved the heart. The Ancient Greek philospher, Aristotle, thought the brain was a radiator for cooling the blood. Rene Descartes, the French scientist, gave it a little more respect, concluding that it was a sort of antenna by which the spirit might commune with the body. It is only now that the full wonder of the brain is being realized. The most basic function of the brain is to keep the rest of the body alive. Among your brain’s 100 bil-
lion neurons, some regulate your breathing, heartbeat, and blood pressure and others control hunger, thirst, sex drive, and sleep cycle. In addition to this, the brain generates the emotions, perceptions, and thoughts that guide your behavior. Then it directs and executes your actions. Finally, it is responsible for the conscious awareness of the mind itself.
What we do know is that it’s the organ that makes us human, giving people the capacity for art, language, moral judgments, and rational thought. It’s also responsible for each individual’s personality, memories, movements, and how we sense the world.
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ll this comes from a jellylike mass of fat and protein weighing about 3 pounds (1.4 kilograms). It is, nevertheless, one of the body’s biggest organs, consisting of some 100 billion nerve cells that not only put together thoughts and highly coordinated physical actions but regulate our unconscious body processes, such as digestion and breathing. The brain’s nerve cells are known as neurons, which make up the organ’s so-called “gray matter.” The neurons transmit and gather electrochemical signals that are communicated via a network of millions of nerve fibers called dendrites and axons. These are the brain’s “white matter.” The cerebrum is the largest part of the brain, accounting for 85 percent of the organ’s weight. The distinctive, deeply wrinkled outer surface is the cerebral cortex, which consists of gray matter. Beneath this lies the white matter. It’s the
cerebrum that makes the human brain—and therefore humans—so formidable. Whereas animals such as elephants, dolphins, and whales have larger brains, humans have the most developed cerebrum. It’s packed to capacity inside our skulls, enveloping the rest of the brain, with the deep folds cleverly maximizing the cortex area. The cerebrum has two halves, or hemispheres. It is further divided into four regions, or lobes, in each hemisphere. It is further divided into four regions, or lobes, in each hemisphere. The frontal lobes, located behind the forehead, are involved with speech, thought, learning, emotion, and movement. Behind them are the parietal lobes, which process sensory information such as touch, temperature, and pain. At the rear of the brain are the occipital lobes, dealing with vision. Lastly, there are the temporal lobes, near the temples, which are involved with hearing and memory.
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gradation of animal forms as a consequence of a gradation of activities is an old idea, dating from Aristotle (E. S. Russell, 1916, p. 15; seep. 4, of this volume). In contrast with plants, “Animals, how-ever, that not only live but feel, present a greater multiformity of parts, and this diversity is greater in some animals than in others, being most varied in those to whose share had fallen not mere life, but life of a high degree. Now such an animal is man” The term “phylogeny” was coined by Ernest Haeckel in 1866 and was defined succinctly by Darwin in the fifth edition of Origin of Species: “Professor Hackel . has recently brought his great knowledge & abilities to bear on what he calls Phylogeny, or the line of descent of all organic beings” (Darwin, 1872, p. xiv). The history of lineages from a stem species was a means of arranging the descriptive data into a scale that Haeckel thought illuminated the evolutionary process. As a modern writer said: “Scale is
everything in history and geology” (Gould, 1995, p. 142). The phylogenetic approach to evolution may be vertical or horizontal depending on the specimens being compared. A vertical study of phylogeny is illustrated in Fig. 1, a series of drawings of a fossil cranium representative of an early species in the human lineage. The series demonstrates the attempt of Sir Arthur Keith (1866-1955), eminent British anatomist and anthropologist, to show that this specimen of Australopithecus africanus revealed more ape-like than hominid characters, “and yet there are suggestions, as Professor Dart maintains, that in its convolutionary organization of the brain of Australopithecus rose above that of either gorilla or chimpanzee”. Keith’s comparison reflects at least four million years of alternating stability and change in brain size, espoused as “punctated” evolution (Eldredge and Gould, 1977). Phylogeny also allows horizontal studies of homologies among forms living at a given time. Comparison of the brain size of modern apes and human be-
ings reveals a fourfold difference-the ratio of brain to body weight is 1:50 in man and about 1:200 in apes. A description of phylogeny as a process was expressed by an English anthropologist, Roger Lewin: [T]he progression through more and more advanced animal groupsfrom amphibians through reptiles to mammals-is marked at each step by a substantial leap in the degree of encephalization displayed by each group as a whole. These stepwise mental increments between the major animal classes reflect gestalt jumps in the complexity of neural processing involved in the animal’s daily lives [sic]. Each increment has been accompanied by an ever greater learning capacity as opposed to geneti-cally determined fixed action patterns (Lewin, 1984, p. 81). Lewin was especially concerned with a second important point, the organization of the brain, specifically the relative proportions of the various lobes. In the human pattern, the
Fig. 1
frontal, temporal, and parietal lobes are predominant and the occipital lobe is relatively small, whereas in the ape this pattern is reversed. The differences are illustrated, for example, by comparisons of the primary visual cortical areas in phylogenetically different species (Fig. 2). In humans, the primary projection area for vision constitutes 2% to 3% of the total cortical area, in apes 8% to 10%, and further down the evolutionary tree, 15% in lemurs (Holloway, 1968, p. 148). Detailed documentation of the relative sizes of primary sensory and motor areas are to be found in Russia at the great primate brain collection of the Moscow Brain Institute. The measurements, accumulated during six decades by institute scientists, show that whereas the primary sensory areas decrease with higher phylogenetic position, the secondary and tertiary sensory regions increase parallel with the development of specific human cognitive processes such as speech and symbolic thinking (Blinkov and Glezer, 1968).
Fig. 2
The changes in functional patterns and relative brain size are accompanied by an increase in the association areas of the cerebrum, interposed between the afferent (incoming) and efferent (out-going) signals and mediating their redistribution. As C. Judson Herrick concluded in his monograph on the two most thoroughly studied brains, the rat’s and man’s: “The enormous increase in size of the human cortex is chiefly in associational fields. Here, then, is to be sought the structural organization upon which depend human culture and the progress of civilization” (1926, p. 265). The belief that a complex social life correlates with a large brain (in proportion to body size) has been widely held to “explain” the chimpanzee’s intellectual superiority over that of other apes. This advantage is not confined to chimpanzees, however. Observations in the wild of the gentle bottlenose dolphin, another “big-brain” mammal, reveal surprising similarities between their social habits and those of chimpanzees in
their natural habitat (Booth, 1988). Although dolphins and chimpanzees evolved separately from a common ancestor about 60 million years ago, in very different environments, their behavioral similarities and relatively large brains with a highly convoluted cortex reinforce the concepts that social interaction and brain development are interdependent. The influence of brain development on the morphology of the vertebrate skull, as shown in Fig. 2.3, was the topic of a comprehensive study of the development of vertebrate skulls by the English biologist, Gavin Rylands De Beer (1899-1972). He drew his conclusions after noting the correlation of bone formation and size of the brain in medical cases of microcephaly, anencephaly, and hydrocephaly. In addition to those “natural” examples, De Beer cited (1937, p. 476 passim) the 1902 report by the German zoologist and embryologist Hans Spemann (1869-1941) of the formation of two osteocrania in Triton after dual brains were experimentally produced.
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he brain is the last of the human organs to give up its secrets. For a long time, people were not even able to understand what the brain is for, the discovery of its anatomy functions, and processes has been a long and slow journey across the millennia. As human knowledge about this mysterious organ has developed and accumulated.
1700 BCE
4000 BCE
Early Sumerian writing notes the eupohoric effect of poppy seeds.
Egyptian papyrus gives a careful description of the brain, but Egyptians do not rate this organ highly; unlike other organs, it is removed and discarded before mummification suggesting that it was not considered to be of any use in future incarnations.
387 BCE
The Greek philosoper Plato teaches at Athens; he believes the brain is the seat of mental processes.
335 BCE
2500 BCE
Trepnation (boring holes into the skull) is a common surgical procedure across many cultures, possibly used for relieving brain disorders such as epilepsy, or for ritual or spiritual reasons.
Greek philosopher Aristotle restates the ancient belief that the heart is the superior organ; the brain, a radiator to sto the body from overheating.
170 BCE
Roman physician Gal human moods and di due to the four humo are held in the brain’s idea persists for more Galen’s anatomical de by generations of phy mainly on work on m
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ind has been variously defined as that which is responsible for one’s thoughts and feelings, the seat of the faculty of reason or the aspect of intellect and consciousness experienced as combinations of thought, perception, memory, emotion, will and imagination, including all unconscious cognitive processes. The term is often used to refer, by implication, to the thought processes of reason.
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illennia ago, we embarked on a quest for knowledge of the wonderful structure of man. The organ that puzzled earlier observers most was the human brain. Despite our many explorations, we remained in awe of this organ. The evolution of our knowledge of the structure and function of the brain has been amply documented in volumes ranging from McHenry’s revision of Dr. Fielding Garrison’s work in 1969 (McHenry, 1969) to the more recent History of Neurology, edited by Finger and colleagues (Finger et al., 2009). Dr. Susan Greenfield’s book (Greenfield, 1997), intended for the lay person, embodies much useful information. We are now aware of
nerve cells, their connections and their modes of communication amongst themselves and with a variety of other structures. Injury to, and disease in, the brain often provides crucial insights on the role of its different parts. A dramatic example is the injury suffered by American railway foreman, Phineas Gage in 1848. Before his accident, Gage was liked by friends and acquaintances who considered him to be honest, trustworthy, hard working and dependable. A freak accident caused a metal tamping rod to enter under his left zygomatic arch and exit through the top of his skull (Barker, 1995). The accident left him with little if any intellectual impairment but af-
ter the accident, Gage became vulgar, irresponsible, capricious and prone to profanity. The company that had previously regarded him as the most efficient and capable of their employees dismissed him from his job. His change in character after the accident made this the index case for personality change due to frontal lobe damage. Subsequent studies (See, for example, Blumer and Benson, 1975) have shown a wide spectrum of abnormal behaviour (compulsive and explosive actions, lack of inhibition, unwarranted maniacal suspicion and alcohol and drug abuse) after injuries to and disease in the frontal or temporal lobes and their pathways to the deeper regions of the brain.
Similar abnormalities also follow chemical derangements in the brain. Modern marvels such as computerised tomography and magnetic resonance imaging of the nervous system have provided significant additional data. Functional magnetic resonance imaging now allows us to further localise function within the structure of the brain and correlate abnormalities of its structure and function. Even so, two entities remain enigmatic: the mind and the soul. Where are they located? Do they lie within the brain? Since neurophysicians treat patients with a wide variety of abnormalities of the brain and neurosurgeons lay bare
the brain and often work in its interior, can they provide insights? Neurologists and neurosurgeons rank high among scientists participating in philosophical debates about what might extend beyond the physical world. They are constantly dealing with patients who have fallen into the deep hole of unconsciousness. In their attempts at restoring normalcy to bodies and minds, they also grapple with life and death. Inevitably, they ponder spirituality and the dominion of the soul.
Where is the Mind Located?
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rishnamoorthy (2009) uses an analogy based on computers to explain the workings of the mind: ‘The mind‌ is a virtual entity, one that reflects the workings of the neural networks, chemical and hormonal systems in our brain.’ The mind cannot be localised to particular areas within the brain, though the entire cerebral cortex and deep grey matter form important components. Consciousness, perception, behaviour, intelligence, language, motivation, drive, the urge to excel and reasoning of the most complex kind are the product of the extensive and complex linkages between the different parts of the brain. Likewise, abnormalities attributed to the mind, such as the spectrum of disorders dealt with by psychiatrists and psychologists, are consequences of widespread abnormalities, often in the chemical processes within different parts of the brain.
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rioreschi (1996) concluded that by the end of the 5th century B.C., the question of whether the heart or the brain was the seat of intelligence remained unresolved in Western medicine. This changed with the works of Hippocrates (ca. 460 BC–ca. 370 BC), ‘a figure of heroic proportions even if dimmed by the mist of time.’ Hippocrates’ oft-quoted statements show a clear understanding of the role of the brain vis-à-vis the mind: ‘Men ought to know that from
the brain, and from the brain alone, arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, griefs and tears. Through it, in particular, we think, see, hear and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant… I hold that the brain is the most powerful organ of the human body… wherefore I assert that the brain is the interpreter of consciousness…’ (Hippocrates:
On the sacred disease. Quoted by Prioreschi [1996]) In talking of the brain as an organ, Hippocrates very clearly refers to those functions which we ordinarily include in our understanding of the ‘mind.’ He talks of emotive mental functions like pleasures, joys, laughter and jests, sorrows, pains, griefs and tears; cognitive mental functions like thinking and seeing; aesthetic mental functions like distinguishing the ugly from the beautiful, the pleasant from the
unpleasant and ethical functions like distinguishing the bad from the good–all these as attributes of the brain, and brain alone. By which he really makes a clear connection between mental functions as we understand them (‘mind’) and the structure that produces it (brain). In his book De anima (On the soul), Aristotle (384 BC–322 BC) felt that man is born with a blank slate (tabula rasa) on which experiences and perceptions are written to form the mind. Although tabula
rasa is a concept traditionally attributed to Locke, Aristotle first referred to it. See Part 4 of Aristotle’s ‘On the soul’, the second-last paragraph.(Aristotle, 2009): ‘Have not we already disposed of the difficulty about interaction involving a common element, when we said that mind is in a sense potentially whatever is thinkable, though actually it is nothing until it has thought? What it thinks must be in it just as characters may
be said to be on a writing tablet on which as yet nothing actually stands written: this is exactly what happens with mind.’ Over the centuries that followed Avicenna (981–1037), Ibn Tufail (c. 1105–1185), Thomas Aquinas (ca. 1225–1274), Thomas Hobbes (1588–1679), John Locke (1632– 1704), Sigmund Freud (1856– 1939) and others commented on this theme. (See Trimble, 2007.)
A theory by Benjamin W. Betts
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enjamin Betts was born in the year 1832. He was educated in England as an architect, and showed considerable promise of success ; but no system of architecture not fully based on mathematics could satisfy him, and he felt that decorative art should not be altogether arbitrary and conventional, nor yet a slavish reproduction of natural forms, but should be executed with understanding according to sound principles of scientific conventionalisation. His mind turned towards the study of internal truth, and he resolved to quit his intended career in order to think out his philosophy of life. He went abroad to secure the quiet and freedom from distraction which the abstruse nature of his studies required, but the solitude in which he has lived, while aiding his spiritual conceptions, has proved a
hindrance when he wished to give out the result of his thought to the world, for having lived so much apart from men it has become very difficult for him to make his ideas intelligible to others. After spending some time in India and the East, he obtained a post in the Government Civil Service, at Auckland, New Zealand, as Trigonometrical Computer oftheSurveyDepartment. Fromthis*hedrawsa modest income which enables him to devote all his leisure time to the metaphysical studies he delights in. The study of internal truth by degrees connected itself in his mind with ideas of form, which combination was probably the result of his early training in Decorative and Architectural Art. An analogy used by Fichte in “ The Science of Knowledge,” of the correspon-
dence of the line and the circle with modes of consciousness, led to his conception of the idea of developingaScienceofRepresentation. Heperceived with Leo Grindon that “ all forms are representative, and their significance is the science of sciences.” When he had succeeded in developing the plane forms which are his symbols of sense-consciousness, he sent them with a letter to Mr. Ruskin, but Mr. Ruskin failed to perceive the intention of the diagrams, and replied that Art must be spontaneous, and could not be made mechanical, supposing that Mr. Betts was attempting some new departure in Art, not in meta- physical science. Later, when Mr. Betts had also developed the corolla forms, he sent the series of diagrams to his sister, with a manuscript in which he attempted to explain them to her.
For, practically as well as theoretically, Mr. Betts holds the opinion that for all true work a union of the male and female mind is required. Miss Betts, though sincerely anxious to help and sympathise with her brother in his studies, had not the mathematical and metaphysical training which might have enabled her to be of service to him, besides which Mr. Betts imagined that the significance of his representative forms was self- evident, so his manuscript was devoted rather to the outpouring of the emotion which the contemplation of the spiritual evolution of Man inspired in him than an accurate explanation of his system of symbology.
After the lapse of some time Mr. Betts’s diagrams were sent to Mrs. George Boole, the widow of the mathematician. Mrs. Boole was much fascinated by the diagrams, rather from the mathematical than the metaphysical point of view. She carried on a long correspondence with Mr. Betts, and made some allu- sions to his work in a little book entitled “ Symbolic Methods of Study,” which she published in 1884. Also she showed the diagrams to many mathematical and scientific friends ; among others to the late James Hinton and the late Mr. Spottiswoode, President of the Royal Society, as well as to many artists. All allowed that Mr. Betts
appeared to have got hold of some idea, but to discover exactly what it was required more labour and time than men immersed in important work of their own could give to it. Mr. Julian Hawthorne also was interested in Mr. Betts’s work. He was on the point of starting for America when it was shown to him, so that he was not able to study it to any considerable extent, but he felt that even if it was not all that Mr. Betts claimed it to be, at least the work had a human interest, and ought to be preserved as being the life-work of an individual thinker.
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he symbolic forms which Mr. Betts has evolved through his system of Representation resemble, when developed in two dimensions, conventionalised but very scientifically and beautifully conventionalised leaf outlines. When in more than two dimensions they approximate to the forms of flowers and crystals. These mathematical curves might serve as a truer and more scientific basis of classification for Botany than de Candolle’s system or any other yet employed, many so-called amorphous developments of the Flora being readily reducible to law according to this method. For instance, the simple corollas,
the horn- shaped corollas, and the bi-axial corollas would supply three main classes of flower forms, each of which might be divided into various distinct sub-classes. The fact that he has accidentally portrayed plant-forms when he was studying human evolution is an assurance to Mr. Betts of the fitness of the symbols he has developed, as it affords presumptive evidence that the laws he is studying intuitively admit of universal application. Mr. Betts’s Representative diagrams trace the path of the monad through five planes or standing-grounds of human evolution. He commences from the animal basis, which he takes as the
zero or starting-point of the human scale of progression, and proceeding onwards and upwards ends with that culmination of human possibilities when man becomes more than man, and his further evolution must be as a being on such a transcendent plane of existence that it might be called divine. All attempts to trace the course of the evolution of life must begin at some point of the eternal circle. Mr. Betts has begun with the evolution of man, but the principles of evolution which he discovers through his studies apply equally to the evolutions of higher or lower forms of consciousness, and even to those planes of existence which
we usually term inanimate. Only by studying ourselves, he believes, can we ever arrive at a true knowledge of the external. The starting-point of the human evolution is the animal sense-consciousness, which, though a positive plane of life for the lower animals, affords but a nega- tive basis of consciousness for man. The symbolic representation of animal sense-consciousness is in two dimensions, and in form resembles a leaf whose apex is about equal to a right angle.
Carter, Rita, Susan Aldridge, Martyn Page, Steve Parker, Christopher D. Frith, Uta Frith, and Melanie B. Shulman. The Human Brain Book. 2nd ed. London: DK Pub., 2009. Print. Cook, Louisa S. Geometrical Psychology, Or, The Science of Representation: An Abstract of the Theories and Diagrams of B.W. Betts. London: G. Redway, 1887. Print. Marshall, Louise H., and Horace Winchell Magoun. Discoveries in the Human Brain: Neuroscience Prehistory, Brain Structure, and Function. Totowa, NJ: Humana, 1998. Print. Pandya, Sunil K. “Understanding Brain, Mind and Soul: Contributions from Neurology and Neurosurgery.” Mens Sana Monographs 9.1 (2011): 129–149. PMC. Web. 9 Dec. 2014.