Gerald Edelman
Encyclopedia
Gerald Maurice Edelman is an American biologist
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

 who shared the 1972 Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...

 for work with Rodney Robert Porter
Rodney Robert Porter
Rodney Robert Porter, FRS was an English biochemist and Nobel laureate.Born in Newton-le-Willows, St Helens, Lancashire, England, Rodney Robert Porter received his Bachelors of Sciences degree from the University of Liverpool in 1939 for Biochemistry. He moved to the University of Cambridge where...

 on the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

. Edelman's Nobel Prize-winning research concerned discovery of the structure of antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

 molecules. In interviews, he has said that the way the components of the immune system evolve over the life of the individual is analogous to the way the components of the brain evolve in a lifetime. There is a continuity in this way between his work on the immune system, for which he won the Nobel Prize, and his later work in neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...

 and in philosophy of mind
Philosophy of mind
Philosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...

.

Education and career

Gerald Edelman was born in 1929 in Ozone Park, Queens, New York to Jewish parents, physician
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

 Edward Edelman, and Anna Freedman Edelman, who worked in the insurance industry. After being raised in New York, he attended college in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...

 where he graduated magna cum laude with a B.S.
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...

 from Ursinus College
Ursinus College
Ursinus College is a liberal arts college in Collegeville, Montgomery County, Pennsylvania.-History:1867Members of the German Reformed Church begin plans to establish a college where "young men could be liberally educated under the benign influence of Christianity." These founders were hoping to...

 in 1950 and received an M.D.
Doctor of Medicine
Doctor of Medicine is a doctoral degree for physicians. The degree is granted by medical schools...

 from the University of Pennsylvania School of Medicine
University of Pennsylvania School of Medicine
The Perelman School of Medicine , formerly the University of Pennsylvania School of Medicine, was founded in 1765, making it the oldest American medical school. As part of the University of Pennsylvania, it is located in the University City section of Philadelphia, Pennsylvania. It is widely...

 in 1954.

After a year at the Johnson Foundation for Medical Physics, he became a house officer
Residency (medicine)
Residency is a stage of graduate medical training. A resident physician or resident is a person who has received a medical degree , Podiatric degree , Dental Degree and who practices...

 at the Massachusetts General Hospital
Massachusetts General Hospital
Massachusetts General Hospital is a teaching hospital and biomedical research facility in the West End neighborhood of Boston, Massachusetts...

 and then practiced medicine in France while serving with US Army Medical Corps
Army Medical Department (United States)
The Army Medical Department of the U.S. Army – known as the AMEDD – comprises the Army's six medical Special Branches of officers and medical enlisted soldiers. It was established as the "Army Hospital" in July 1775 to coordinate the medical care required by the Continental Army during the...

. Edelman joined the Rockefeller Institute for Medical Research
Rockefeller University
The Rockefeller University is a private university offering postgraduate and postdoctoral education. It has a strong concentration in the biological sciences. It is also known for producing numerous Nobel laureates...

 as a graduate fellow in 1957, working in the laboratory of Henry Kunkel and receiving a Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...

 in 1960. Rockefeller made him the Assistant (later Associate) Dean of Graduate Studies until 1966, when he became a professor at the school. In 1992, he moved to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 and became a professor of neurobiology at The Scripps Research Institute
The Scripps Research Institute
The Scripps Research Institute is an American medical research facility that focuses on research in the basic biomedical sciences. Headquartered in La Jolla, California, with a sister facility in Jupiter, Florida, the institute is home to 3,000 scientists, technicians, graduate students, and...

.

After his Nobel prize award, Edelman began research into the regulation of primary cellular processes, particularly the control of cell growth and the development in multi-celled organisms, focussing on cell-to-cell interactions in early embryonic development and in the formation and function of the nervous system. These studies led to the discovery of cell adhesion molecules (CAMs), which guide the fundamental processes that help an animal achieve its shape and form, and by which nervous systems are built. One of the most significant discoveries made in this research is that the precursor gene for the neural cell adhesion molecule gave rise in evolution to the entire molecular system of adaptive immunity.

Edelman is the founder and director of The Neurosciences Institute
The Neurosciences Institute
The Neurosciences Institute is a non-profit, scientific research organization dedicated to learning about the brain. Under the leadership of Nobel Laureate Gerald M...

, a nonprofit research center in San Diego that studies the biological bases of higher brain function in humans, and is on the scientific board of the World Knowledge Dialogue project

Edelman is a member of the USA Science and Engineering Festival
USA Science and Engineering Festival
USA Science and Engineering Festival was a science festival in Washington, D.C. that founder Larry Book deemed the country’s first national science festival. The inaugural event was held from October 10, 2010 through October 24, 2010 and was planned to be a yearly event. The two week festival...

's Advisory Board.

Nobel Prize

While in Paris serving in the Army, Edelman read a book that sparked his interest in antibodies
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

. He decided that, since the book said so little about antibodies, he would investigate them further upon returning to the United States, which led him to study physical chemistry
Physical chemistry
Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts...

 for his 1960 Ph.D. Research by Edelman and his colleagues and Rodney Robert Porter
Rodney Robert Porter
Rodney Robert Porter, FRS was an English biochemist and Nobel laureate.Born in Newton-le-Willows, St Helens, Lancashire, England, Rodney Robert Porter received his Bachelors of Sciences degree from the University of Liverpool in 1939 for Biochemistry. He moved to the University of Cambridge where...

 in the early 1960s produced fundamental breakthroughs in the understanding of the antibody's chemical structure, opening a door for further study. For this work, Edelman and Porter shared the Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...

 in 1972.

In its Nobel Prize press release in 1972, the Karolinska Institutet
Karolinska Institutet
Karolinska institutet is a medical university in Solna within the Stockholm urban area, Sweden, and one of Europe's largest medical universities...

 lauded Edelman and Porter's work as a major breakthrough:

Disulphide bonds

Edelman's early research on the structure of antibody proteins revealed that disulphide bonds link together the protein subunits. The protein subunits of antibodies are of two types, the larger heavy chains and the smaller light chains. Two light and two heavy chains are linked together by disulphide bonds to form a functional antibody.

Molecular models of antibody structure

Using experimental data from his own research and the work of others, Edelman developed molecular models of antibody proteins. A key feature of these models included the idea that the antigen
Antigen
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by the immune system. The immune system will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader. These invaders can be molecules such as...

 binding domains of antibodies (Fab) include amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s from both the light
Immunoglobulin light chain
]The immunoglobulin light chain is the small polypeptide subunit of an antibody .A typical antibody is composed of two immunoglobulin heavy chains and two Ig light chains.-In humans:...

 and heavy protein subunits. The inter-chain disulphide bonds help bring together the two parts of the antigen binding domain.

Antibody sequencing

Edelman and his colleagues used cyanogen bromide and protease
Protease
A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

es to fragment the antibody protein subunits into smaller pieces that could be analyzed for determination of their amino acid sequence
Protein sequencing
Protein sequencing is a technique to determine the amino acid sequence of a protein, as well as which conformation the protein adopts and the extent to which it is complexed with any non-peptide molecules...

. At the time when the first complete antibody sequence was determined (1969) it was the largest complete protein sequence that had ever been determined. The availability of amino acid sequences of antibody proteins allowed recognition of the fact that the body can produce many different antibody protein with similar antibody constant regions and divergent antibody variable regions.

Topobiology

Topobiology is an Edelman’s theory which asserts that morphogenesis is driven by differential adhesive interactions among heterogeneous cell populations and it explains how a single cell can give rise to a complex multi-cellular organism. As proposed by
Edelman in 1988 topobiology is the process that sculpts and maintains differentiated tissues and is acquired by the energetically favored segregation of cells through heterologous cellular interactions.

Theory of consciousness

Edelman is noted for his theory of consciousness
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

, which he has documented in a trilogy of technical books, and in several subsequent books written for a general audience including Bright Air, Brilliant Fire (1992), A Universe of Consciousness (2001, with Giulio Tononi), Wider than the Sky (2004) and Second Nature: Brain Science and Human Knowledge (2007).

In Second Nature Edelman defines human consciousness as being:
"... what you lose on entering a dreamless deep sleep ... deep anesthesia or coma ... what you regain after emerging from these states. [The] experience of a unitary scene composed variably of sensory responses ... memories ... situatedness ... "


The first of Edelman's technical books, Neural Darwinism (1987) explores his theory of memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

 that is built around the idea of plasticity in the neural network in response to the environment. The second book, Topobiology (1988), proposes a theory of how the original neuronal network of a newborn's brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 is established during development of the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

. The Remembered Present (1990) contains an extended exposition of his theory of consciousness
Consciousness
Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

.

Edelman has asked whether we should attempt to construct models of functioning mind
Mind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

s or models of brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

s which, through interactions with their surroundings, can develop minds. His answer is that we should make model brains and pay attention to how they interact with their environment. Edelman accepts the existence of qualia
Qualia
Qualia , singular "quale" , from a Latin word meaning for "what sort" or "what kind," is a term used in philosophy to refer to subjective conscious experiences as 'raw feels'. Examples of qualia are the pain of a headache, the taste of wine, the experience of taking a recreational drug, or the...

 and incorporates them into his brain-based theory of consciousness. His concept of qualia attempts to avoid the pitfalls of the idea of special qualia with non-functional properties, which was criticized by Daniel Dennett
Daniel Dennett
Daniel Clement Dennett is an American philosopher, writer and cognitive scientist whose research centers on the philosophy of mind, philosophy of science and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. He is currently the Co-director of...

.

Edelman proposes a biological theory of consciousness, based on his studies of the immune system. He explicitly locates his theory within Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

's Theory of Natural Selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

, citing the key tenets of Darwin's population theory, which postulates that individual variation within species provides the basis for the natural selection that eventually leads to the evolution of new species. He rejects dualism
Dualism (philosophy of mind)
In philosophy of mind, dualism is a set of views about the relationship between mind and matter, which begins with the claim that mental phenomena are, in some respects, non-physical....

 and also dismisses newer hypotheses such as the so-called 'computational' model of consciousness, which liken the brain's functions to the operations of a computer.

Edelman argues that the mind and consciousness are wholly material and purely biological phenomena, arising from highly complex cellular processes within the brain, and that the development of consciousness and intelligence can be satisfactorily explained by Darwinian theory.

In Edelman's view, human consciousness depends on and arises from the uniquely complex physiology of the human brain:
  • the vast number of neurons and associated cells in the brain
  • the almost infinitely complex physiological variations in neurons (even of the same general type) and in their connections with other cells
  • the massive multiple parallel reentrant
    Reentry (neural circuitry)
    Reentry is a neural structuring of the brain, specifically in humans, which is hypothesized to allow for widely distributed groups of neurons to achieve integrated and synchronized firing, which is proposed to be a requirement for consciousness, as outlined by Gerald Edelman and Giulio Tononi in...

     connections between individual cells, and between larger neuronal groups, and so on, up to entire functional regions and beyond.


Edelman's theory is strongly anti-reductionist and seeks to explain consciousness by reference to the extraordinarily rich and complex morphology of the brain. A newborn baby's brain comprises a massive population of neurons (approx. 100 billion cells) and those that survive the initial phases of growth and development will make approximately 100 trillion connections with each other. A sample of brain tissue the size of a match head contains about a billion connections, and if we consider how these neuronal connections might be variously combined, the number of possible permutations becomes hyper-astronomical—in the order of ten followed by millions of zeros. The young brain contains many more neurons than will ultimately survive to maturity and Edelman argues that this great redundant capacity is needed because neurons are the only cells in the body that cannot be renewed and because only those cells and networks best adapted to their ultimate purpose will be selected as they organise into neuronal groups.

Neural Darwinism

Edelman's theory of neuronal group selection, also known as Neural Darwinism
Neural Darwinism
Neural Darwinism, a large scale theory of brain function by Gerald Edelman, was initially published in 1978, in a book called The Mindful Brain...

, has three basic tenets—Developmental Selection, Experiential Selection and Reentry.
  • Developmental selection -- the formation of the gross anatomy of the brain is controlled by genetic factors, but in any individual the connectivity between neurons at the synaptic level and their organisation into functional neuronal groups is determined by somatic selection during growth and development. This process generates tremendous variability in the neural circuitry—like the fingerprint
    Fingerprint
    A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. In a wider use of the term, fingerprints are the traces of an impression from the friction ridges of any part of a human hand. A print from the foot can also leave an impression of friction ridges...

     or the iris
    Iris (anatomy)
    The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

    , no two people will have precisely the same synaptic structures in any comparable area of brain tissue. Their high degree of functional plasticity and the extraordinary density of their interconnections enables neuronal groups to self-organise into many complex and adaptable "modules". These are made up of many different types of neurons which are typically more closely and densely connected to each other than they are to neurons in other groups.

  • Experiential selection -- Overlapping the initial growth and development of the brain, and extending throughout an individual's life, a continuous process of synaptic selection occurs within the diverse repertoires of neuronal groups. This process may strengthen or weaken the connections between groups of neurons and it is constrained by value signals that arise from the activity of the ascending systems of the brain, which are continually modified by successful output. Experiential selection generates dynamic systems that can 'map' complex spatio-temporal events from the sensory organs, body systems and other neuronal groups in the brain onto other selected neuronal groups. Edelman argues that this dynamic selective process is directly analogous to the processes of selection that act on populations of individuals in species, and he also points out that this functional plasticity is imperative, since not even the vast coding capability of entire human genome is sufficient to explicitly specify the astronomically complex synaptic structures of the developing brain.

  • Reentry -- the third tenet of Edelman's thesis is the concept of reentrant signalling between neuronal groups. He defines reentry as the ongoing recursive dynamic interchange of signals that occurs in parallel between brain maps, and which continuously interrelates these maps to each other in time and space (film clip: Edelman demonstrates spontaneous group formation among neurons with re-entrant connections ). Reentry depends for its operations on the intricate networks of massively parallel reciprocal connections within and between neuronal groups, which arise through the processes of developmental and experiential selection outlined above. Edelman describes reentry as "a form of ongoing higher-order selection ... that appears to be unique to animal brains" and that "there is no other object in the known universe so completely distinguished by reentrant circuitry as the human brain".

Evolution Theory

Edelman and Gally were the first to point out the pervasiveness of Degeneracy
Degeneracy (biology)
Within biological systems, degeneracy refers to circumstances where structurally dissimilar components/modules/pathways can perform similar functions under certain conditions, but perform distinct functions in other conditions. Degeneracy is thus a relational property that requires comparing the...

 in biological systems and the fundamental role that degeneracy plays in facilitating evolution.

Personal

Edelman married Maxine M. Morrison in 1950. They have two sons, Eric, a visual artist in New York City, and David, a neuroscientist at the Neurosciences Institute. Their daughter, Judith Edelman, is a bluegrass
Bluegrass music
Bluegrass music is a form of American roots music, and a sub-genre of country music. It has mixed roots in Scottish, English, Welsh and Irish traditional music...

 musician and recording artist. Some observers have noted that a character in Richard Powers
Richard Powers
Richard Powers is an American novelist whose works explore the effects of modern science and technology.- Life and work :...

' The Echo Maker
The Echo Maker
The Echo Maker is a 2006 novel by American writer Richard Powers which won the National Book Award for fiction. It was a finalist for the 2007 Pulitzer Prize for Fiction.-Plot introduction:...

 may be a nod at Edelman.

See also

  • Biologically inspired computing
  • Embodied philosophy
  • Embodiment
    Embodiment
    Embodied or embodiment may refer to:in psychology and philosophy,*Embodied cognition , a position in cognitive science and the philosophy of mind emphasizing the role that the body plays in shaping the mind...

  • Reentry (neural circuitry)
    Reentry (neural circuitry)
    Reentry is a neural structuring of the brain, specifically in humans, which is hypothesized to allow for widely distributed groups of neurons to achieve integrated and synchronized firing, which is proposed to be a requirement for consciousness, as outlined by Gerald Edelman and Giulio Tononi in...

  • List of Jewish Nobel laureates

Further reading

(originally published in Artificial Intelligence
Artificial Intelligence (journal)
Artificial Intelligence is a scientific journal on artificial intelligence research. It was established in 1970 and is published by Elsevier. The journal is abstracted and indexed in Scopus and Science Citation Index. The 2009 Impact Factor for this journal is 3.036 and the 5-Year Impact Factor is...

39 (1989) 121-139.)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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