Jean-Pierre Changeux
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Jean-Pierre Changeux (; born 6 April 1936) is a French
neuroscientist A neuroscientist (or neurobiologist) is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, Biological neural network, n ...
known for his research in several fields of
biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary i ...
, from the structure and function of
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s (with a focus on the
allosteric In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric site ...
proteins), to the early development of the
nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
up to cognitive functions. Although being famous in biological sciences for the
MWC model In biochemistry, the Monod-Wyman-Changeux model (MWC model, also known as the symmetry model) describes allosteric transitions of proteins made up of identical subunits. It was proposed by Jean-Pierre Changeux in his PhD thesis, and described by ...
, the identification and purification of the
nicotinic acetylcholine receptor Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ne ...
and the theory of epigenesis by synapse selection are also notable scientific achievements. Changeux is known by the non-scientific public for his ideas regarding the connection between mind and physical brain. As put forth in his book, ''Conversations on Mind, Matter and Mathematics'', Changeux strongly supports the view that the nervous system functions in a projective rather than reactive style and that interaction with the environment, rather than being instructive, results in the selection amongst a diversity of preexisting internal representations.


Biography

Changeux was born in
Domont Domont () is a Communes of France, commune in the Val-d'Oise Departments of France, department and ÃŽle-de-France Regions of France, region of France. It is twinned with the Leicestershire village of Shepshed. Domont station has rail connections ...
, France to Marcel Changeux and Jeanne Benoît. He entered the
École Normale Supérieure École may refer to: * an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing in région Île-de-France * École, Savoi ...
in 1955, where he obtained a
bachelor's degree A bachelor's degree (from Middle Latin ''baccalaureus'') or baccalaureate (from Modern Latin ''baccalaureatus'') is an undergraduate academic degree awarded by colleges and universities upon completion of a course of study lasting three to six ...
(''Licence'') in 1957 and a
master's degree A master's degree (from Latin ) is an academic degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional practice.
(''Diplome d'Études Supérieure'') in 1958. He also received his
agrégation In France, the ''agrégation'' () is a competitive examination for civil service in the French public education system. Candidates for the examination, or ''agrégatifs'', become ''agrégés'' once they are admitted to the position of ''professe ...
in natural science the same year. He began his scientific career during his ENS years during summer internships in
Banyuls-sur-Mer Banyuls-sur-Mer (; ) is a commune in the Pyrénées-Orientales department in southern France. It was first settled by Greeks starting in 400 BCE. Geography Location Banyuls-sur-Mer is located in the canton of La Côte Vermeille and in the ar ...
where he identified a new genus of parasitic
Copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...
. He pursued
PhD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * ''Piled Higher and Deeper'', a web comic * Ph.D. (band), a 1980s British group ** Ph.D. (Ph.D. albu ...
studies at the
Pasteur Institute The Pasteur Institute (french: Institut Pasteur) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines f ...
under the direction of
Jacques Monod Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and André Lwoff "for their discoveries concerning genetic control of en ...
and Francois Jacob, and gained his doctorate in 1964. Changeux then left France for postdoctoral studies first at the
University of California Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant univ ...
(1965–1966) then at
Columbia University College of Physicians and Surgeons Columbia University Vagelos College of Physicians and Surgeons (VP&S) is the graduate medical school of Columbia University, located at the Columbia University Irving Medical Center in the Washington Heights neighborhood of Manhattan. Founded i ...
, New-York (1967). He returned to France as attaché to the chair of Molecular Biology held by
Jacques Monod Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and André Lwoff "for their discoveries concerning genetic control of en ...
. In 1972, he became director of the Unit of Molecular Neurobiology at the
Pasteur Institute The Pasteur Institute (french: Institut Pasteur) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines f ...
, where he received a professorship in 1975. In 1975, Changeux was elected professor at the
Collège de France The Collège de France (), formerly known as the ''Collège Royal'' or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment (''grand établissement'') in France. It is located in Paris ne ...
, chair of Cell Communications, position that he held until 2006. Changeux is author of more than 600 scientific articles and several books, technical or for general audience.


Scientific achievements

All his scientific career, Changeux has been faithful to a handful of scientific questions, at molecular, cellular and brain levels. If one needs to seek a unifying theme to all of them, it is the conviction that selection is the basis of life processes, rather than instruction. While started as separate lines of investigations, all the research threads were tied in the recent decades within the study of allosteric mechanisms as a basis of for the involvement of
nicotinic receptors Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ner ...
in
cognitive functions Cognitive skills, also called cognitive functions, cognitive abilities or cognitive capacities, are brain-based skills which are needed in acquisition of knowledge, manipulation of information and reasoning. They have more to do with the mechanisms ...
.


Allostery

During his
PhD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * ''Piled Higher and Deeper'', a web comic * Ph.D. (band), a 1980s British group ** Ph.D. (Ph.D. albu ...
studies in the laboratory of
Jacques Monod Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and André Lwoff "for their discoveries concerning genetic control of en ...
and Francois Jacob, Changeux studied the
allosteric regulation In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric site ...
s of
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s, that is the modulation of their activity by compounds different from their substrates.Changeux J.-P. (1961). The feedback control mechanism of biosynthetic L-threonine deaminase by L-isoleucine. Cold Spring Harbor. Symp. Quant. Biol. 26: 313-318.Changeux J.-P. (1963). Allosteric Interactions on biosynthetic L-theonine deaminase from E. coli K12. Cold Spring Harb Symp Quant Biol, 28: 497-504Monod J., Changeux J.-P., and Jacob. F. (1963). Allosteric proteins and cellular control systems. J. Mol. Biol. 6: 306-329 This work led to the development of the model of concerted transitions for
allosteric In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric site ...
proteins.Monod J., Wyman J., and Changeux J.-P. (1965). On the nature of allosteric transitions: a plausible model. J. Mol. Biol. 12: 88-118.Rubin M.M., Changeux J.-P. (1966). On the nature of allosteric transitions ; implications of non-exclusive ligand binding. J. Mol. Biol. 21: 265-274. The main ideas behind this theory are: 1)
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s can exist under various conformations in
thermal equilibrium Two physical systems are in thermal equilibrium if there is no net flow of thermal energy between them when they are connected by a path permeable to heat. Thermal equilibrium obeys the zeroth law of thermodynamics. A system is said to be in ...
in the absence of regulators. The allosteric regulators merely shift the equilibrium between the conformations, stabilizing the ones for which they display the highest affinity, and 2) all the subunits of a symmetrical multimeric protein exist in the same conformation, the transition taking place in a ''concerted'' fashion. The resulting model explains the observed ''cooperativity'' without a progressive change of biophysical parameters. This conceptual framework is still the principal model used to explain the function of cooperative proteins such as
hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
. In his PhD thesis, Changeux suggested that the recognition and transmission of signals by
membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. B ...
, and in particular by
synapses In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from ...
, could use the same mechanisms as the allosteric regulation of enzymes. More than forty years of research would follow, mainly focussed on nicotinic acetylcholine receptors (see below). In 1967, Changeux extended the MWC model to bi-dimensional lattice of
receptors Receptor may refer to: *Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a n ...
Changeux J.-P., Thiéry J.-P., Tung Y., and Kittel C. (1967). On the cooperativity of biological membranes. Proc. Natl. Acad. Sci. USA 57, 335-341. (an idea that would also be developed three decades afterward by Dennis BrayBray D, Levin MD, Morton-Firth CJ (1998) Receptor clustering as a cellular mechanism to control sensitivity. Nature, 393: 85-88.). He then applied this idea to the post-synaptic membrane of
electric organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed ...
s (analog to
striated muscle Striations means a series of ridges, furrows or linear marks, and is used in several ways: * Glacial striation * Striation (fatigue), in material * Striation (geology), a ''striation'' as a result of a geological fault * Striation Valley, in Ant ...
).Changeux J.-P., Podleski T.R. (1968). On the excitability and cooperativity of electroplax membrane. Proc. Natl. Acad. Sci. USA 59:944-950Cartaud J., Benedetti E.L., Cohen J.B., Meunier J.C., Changeux J.-P. (1973) Presence of a lattice structure in membrane fragments rich in nicotinic receptor protein from the electric organ of Torpedo marmorata. FEBS Lett. 33: 109-113. His team demonstrated the existence of several interconvertible states for the nicotinic receptor, resting, open and desensitized, displaying different affinities for the ligands, such as the endogenous agonist
acetylcholine Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Part ...
.Weber M., David-Pfeuty M.T., Changeux J.-P. (1975). Regulation of binding properties of the nicotinic receptor protein by cholinergic ligands in membrane fragments from Torpedo marmorata. Proc. Natl. Acad. Sci. USA 72: 3443-3447.Sugiyama H., Changeux J.-P. (1975). Interconversion between different states of affinity for acetylcholine of the cholinergic receptor protein from Torpedo marmorata. Eur. J. Biochem. 55: 505-515.Heidmann T., Changeux J.-P. (1979). Fast kinetic studies on the interaction of a fluorescent agonist with the membrane-bound acetylcholine receptor from T. marmorata. Eur. J. Biochem. 94: 255-279. The transitions between the states followed different kinetics, and those kinetics plus the differential affinities sufficed to explain the shape of the post-synaptic potential. A full mechanistic model of the nicotinic receptor from striated muscle (or electric organ) was to be provided much later, when Changeux collaborated with Stuart Edelstein, another specialist of allostery, who worked decades on
hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
.Edelstein S., Schaad O., Henry E., Bertrand D. Changeux J.-P. (1996). A kinetic mechanism for nicotinic acetylcholine receptors based on multiple allosteric transitions. Biol. Cybern. 75: 361-379 In addition to the allosteric modulation of the channel gating by the agonists, many other regulations of the ligand-gated ion channels activity have since been discovered. The modulators bind to a variety of allosteric sites, whether on the agonist binding sites, other binding sites at the subunit interfaces, on the cytoplasmic part of the protein or in the transmembrane domain.Changeux J.-P. (2012). The concept of allosteric modulation: an overview. Drug Discov. Today 10: e223-e228 The concept of an allosteric pharmacology for ion channels was developed over the years. In addition to the well known
GABAA receptor positive allosteric modulator In pharmacology, GABAA receptor positive allosteric modulators are positive allosteric modulator (PAM) molecules that increase the activity of the GABAA receptor protein in the vertebrate central nervous system. GABA is a major inhibitory neuro ...
s (such as
benzodiazepines Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, i ...
and
barbiturate Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as we ...
drugs), one can find antiparasitic drug such as
ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat inf ...
and glutamate receptor modulators used against
Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...
such as
aniracetam Aniracetam (brand names Draganon, Sarpul, Ampamet, Memodrin, Referan), also known as ''N''-anisoyl-2-pyrrolidinone, is a racetam which is sold in Europe as a prescription drug. It is not approved by the Food and Drug Administration for use in th ...
.


Nicotinic receptor structure

In 1970, Changeux isolated the
nicotinic acetylcholine receptor Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ne ...
of the eel
electric organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed ...
, the first ever isolated membrane pharmacological receptor,Changeux J.-P., Kasai M., Huchet M., Meunier J.-C. (1970). Extraction à partir du tissu électrique de gymnote d'une protéine présentant plusieurs propriétés caractéristiques du récepteur physiologique de l'acétylcholine. C. R. Acad. Sci. 270D: 2864-2867. that he was able to identify thanks to the properties of a snake toxin, which was purified by Taiwanese researchers CY Lee and CC Chang.Changeux J.-P., Kasai M., and Lee C.Y. (1970). The use of a snake venom toxin to characterize the cholinergic receptor protein. Proc. Natl. Acad. Sci. USA 67: 1241-1247. The isolation of the receptor was also later reported by
Ricardo Miledi Ricardo Miledi (15 September 1927 – 18 December 2017) was a Mexican neuroscientist known for his work deciphering the role of calcium in neurotransmitter release. He also helped to develop a technique for studying native receptors in frog oocyte ...
.Miledi R., Molinoff P., Potter L.T. (1971). Isolation of the cholinergic receptor protein of Torpedo electric tissue. Nature 229:554-557. The improvements of purification methods developed in the groupOlsen R., Meunier J.C., Changeux J.-P. (1972). Progress in purification of the cholinergic receptor protein from Electrophorus electricus by affinity chromatography. FEBS Lett. 28., 96-100. allowed the proposition that the receptor was a
pentameric protein A pentameric protein is a quaternary protein structure that consists of five protein subunits. Examples Ligand-gated ion channels Five sub-units come together to form a channel. Each channel consist of two alpha chain, one beta, one gamma and o ...
,Hucho F., Changeux J.-P. (1973). Molecular weight and quaternary structure of the cholinergic receptor protein extracted by detergents from Electrophorus electricus electric tissue. FEBS Lett. 38: 11-15 a finding quickly confirmed by the team of Arthur Karlin.Weill C.L., McNamee M.G., Karlin A. (1974) Affinity-labeling of purified acetylcholine receptor from Torpedo Californica. Biochem Biophys Res Comm 61: 997-1003. The group of Changeux was among the firsts to elucidate the primary structure of the subunits of the receptor,Devillers-Thiéry A., Changeux J.-P., Paroutaud P., and Strosberg A.D. (1979). The amino-terminal sequence of the 40.000 molecular weight subunit of the acetylcholine receptor protein from Torpedo marmorata. FEBS Lett. 104: 99-105.Devillers-Thiéry A., Giraudat J., Bentaboulet M., Changeux J.-P. (1983). Complete mRNA coding sequence of the acetylcholine binding alpha subunit of Torpedo marmorata acetylcholine receptor: a model for the transmembrane organization of the polypeptide chain. Proc. Natl. Acad. Sci. USA 80: 2067-2071. in parallel with the group of
Shosaku Numa was a Japanese neuroscientist known for his pioneering research on neurotransmitters and ion channels, and for his contributions to the understanding of molecular mechanisms of neural signalling. Biography Numa was born in Wakayama, Japan and ...
Noda M., Takahashi H., Tanabe T., Toyosato M., Furutani Y., Hirose T., Asai M., Inayama S., Miyata T., Numa S. (1982) Primary structure of alpha-subunit precursor of Torpedo californica acetylcholine receptor deduced from cDNA sequence. Nature 299:793-797. and Stephen Heinemann.Ballivet M., Patrick J., Lee J., Heinemann S. (1982) Molecular cloning of cDNA coding for the gamma subunit of Torpedo acetylcholine receptor. Proc Natl Acad Sci U S A. 79:4466-4470. Throughout the 1980s and 1990s, molecular biology technics were used to decipher the tertiary and quaternary structures of the receptor. The location of the ionic pore was identified, made up of the second transmembrane segment,Giraudat J., Dennis M., Heidmann T., Chang J.Y., Changeux J.-P. (1986). Structure of the high affinity site for noncompetitive blockers of the acetylcholine receptor: serine-262 of the delta subunit is labeled by Hchlorpromazine. Proc. Natl. Acad. Sci. USA 83: 2719-2723. as shown also later by the groups of Shosaku NumaImoto K., Methfessel C., Sakmann B., Mishina M., Mori Y., Konno T., Fukuda K., Kurasaki M., Bujo H., Fujita Y., Shosaku N. (1986). Location of a delta-subunit region determining ion transport through the acetylcholine receptor channel. Nature. 1986 Dec 18-31;324(6098):670-4. and Ferdinand Hucho.Hucho F., Oberthür W., Lottspeich F. (1986) The ion channel of the nicotinic acetylcholine receptor is formed by the homologous helices M II of the receptor subunits. FEBS Lett.205: 137-142. The molecular basis of ionic selectivity were also identified in the transmembrane domain.Galzi J.-L., Devillers-Thiery A., Hussy N., Bertrand S., Changeux J.-P., Bertrand D. (1992). Mutations in the ion channel domain of a neuronal nicotinic receptor convert ion selectivity from cationic to anionic. Nature 359: 500-505.Bertrand D., Galzi J.-L., Devillers-Thiéry A., Bertrand S., Changeux J.-P. (1993). Mutations at two distinct sites within the channel domain M2 alter calcium permeability of neuronal alpha7 nicotinic receptor. Proc. Natl. Acad. Sci. USA 90: 6971-6975.Corringer P.-J., Bertrand S., Galzi J.-L., Devillers-Thiéry A., Changeux J.-P., Bertrand D. (1999). Mutational Analysis of the Charge Selectivity Filter of the a7 Nicotinic Acetylcholine Receptor. Neuron 22: 831-843. The structure of the binding site for the acetylcholine and nicotine was located at the interface between adjacent subunits.Dennis M., Giraudat J., Kotzyba-Hibert F., Goeldner M., Hirth C., Chang J.Y., Lazure C., Chrétien M., Changeux J.-P. (1988). Amino acids of the Torpedo marmorata acetylcholine receptor subunit labeled by a photoaffinity ligand for the acetylcholine binding site. Biochemistry 27: 2346-2357.Galzi J.-L., Revah F., Black D., Goeldner M., Hirth C., Changeux J.-P. (1990). Identification of a novel amino acid a-Tyr 93 within the active site of the acetylcholine receptor by photoaffinity labeling: additional evidence for a three-loop model of the acetylcholine binding site. J. Biol. Chem. 265: 10430-10437.Galzi J.-L., Bertrand D., Devillers-Thiéry A., Revah F., Bertrand S., Changeux J.-P. (1991). Functional significance of aromatic amino acids from three peptide loops of the alpha 7 neuronal nicotinic receptor site investigated by site-directed mutagenesis. FEBS Lett. 294: 198-202. The quest of Changeux for the structure of the nicotinic receptor culminated with the publication of the structure, at atomic resolution, of a bacterial homolog in the openBocquet N., Nury H., Baaden M., Le Poupon C., Changeux J.-P., Delarue M., Corringer P.-J. (2009) X-ray structure of a pentameric ligand-gated ion channel in an apparently open conformation. Nature 457(7225):111-114 and resting conformations supporting the concept of a symmetrical concerted opening for channel gating,Hilf R.J., Dutzler R. (2009) Structure of a potentially open state of a proton-activated pentameric ligand-gated ion channel. Nature 457(7225):115-118 in agreement with molecular dynamics simulations.Taly A., Delarue M., Grutter T., Nilges M., Le Novère N., Corringer P.-J., Changeux J.-P. (2005) Normal mode analysis suggests a quaternary twist model for the nicotinic receptor gating mechanism. Biophys. J. 88:3954-3965Calimet N., Simoes M., Changeux J.-P., Karplus M., Taly A., Cecchini M. (2013) From the Cover: A gating mechanism of pentameric ligand-gated ion channels. Proc Natl Acad Sci U S A. 110:E3987-3996


Stabilization of synapses by neuronal activity

In 1973, together with Philippe Courrège and
Antoine Danchin Antoine Danchin (born 7 May 1944) is a French geneticist. He is best known for his research in several fields of biology, from the structure and function of adenylate cyclase, to modelisation of learning in the nervous system and the early develop ...
, Changeux proposed a model describing how, during development of the
nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...
, the activity of a network could cause the stabilization or regression of the
synapses In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from ...
involvedChangeux J.-P., Courrège P., Danchin A. (1973). A theory of the epigenesis of neural networks by selective stabilization of synapses. Proc. Natl. Acad. Sci. USA 70: 2974-2978. and illustrated it with the neuromuscular junction. This model is effectively the precursor of the "neural Darwinism" theory further promoted by
Gerald Edelman Gerald Maurice Edelman (; July 1, 1929 – May 17, 2014) was an American biologist who shared the 1972 Nobel Prize in Physiology or Medicine for work with Rodney Robert Porter on the immune system. Edelman's Nobel Prize-winning research concern ...
. Changeux later extended and illustrated further this idea.Changeux J.-P., Danchin, A. (1976). Selective stabilization of developing synapses as a mechanism for the specification of neuronal networks. Nature 264: 705-712. During the 1970s, he tried to document this phenomenon, either by studying mutant animalsSotelo C., Changeux J.-P. (1974). Transsynaptic degeneration 'en cascade' in the cerebellar cortex of staggerer mutant mice. Brain Res. 67: 519-526.Mariani J., Crepel F., Mikoshiba K., Changeux J.-P. (1977). Anatomical, physiological and biochemical studies of the cerebellum from reeler mutant mouse. Phyl. Trans. Royal Soc. B 281: 1-28 or by experimental denervation. Benoit P, Changeux J.P. (1975) Consequences of tenotomy on the evolution of multiinnervation in developing rat soleus muscle. Brain Res.99:354-8Henderson CE, Huchet M, Changeux JP. Denervation increases a neurite-promoting activity in extracts of skeletal muscle. Nature. 1983 Apr 14;302(5909):609-11.


Nicotinic receptor function

While until the 1990s, Changeux's group studied the structure of the nicotinic receptor present in
electric organ An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed ...
s of electric eel and torpedo, the investigations of the physiological role of those receptors were mostly focussed on two model systems: the nicotinic receptors of the
neuromuscular junction A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber. It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation to ...
, the synapse linking the
motorneuron A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly ...
to the
skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
, and the nicotinic receptors of the brain, notably in relation with nicotine addiction. From the mid-1980s, the group studied the compartimentalisation of the muscle cell upon development, as a model of synaptogenesis and in relation with the theoretical work on epigenesis. In particular, the group focussed on the accumulation of nicotinic receptors in the post-synaptic region upon development, concomitant to a switch of receptor identity. They were able to decrypt the different signalling pathways involved in the response to synaptic activity, showing that the accumulation resulted from an inhibition of gene transcription outside the synaptic region due to electrical activity triggering an uptake of calcium and activation of PKC,Betz H., Changeux J.-P. (1979). Regulation of muscle acetylcholine receptor synthesis in vitro by cyclic nucleotide derivatives. Nature 278: 749-752.Klarsfeld A., Changeux J.-P. (1985). Activity regulates the level of acetylcholine receptor alpha-subunit mRNA in cultured chick myotubes. Proc. Natl. Acad. Sci. USA 82: 4558-4562.Klarsfeld A., Laufer R., Fontaine B., Devillers-Thiéry A., Dubreuil C., Changeux J.-P. (1989). Regulation of muscle AChR alpha-subunit gene expression by electrical activity : involvement of protein kinase C and Ca++. Neuron 2: 1229-1236.Piette J., Bessereau J.-L., Huchet M., Changeux J.-P. (1990). Two adjacent MyoD1-binding sites regulate the expression of the acetylcholine receptor delta-subunit gene. Nature 345: 353-355. and a stimulation of gene transcription at the synapse by the calcitonin gene-related peptide (CGRP) activating PKAFontaine B., Klarsfeld A., Hokfelt T., Changeux J.-P. (1986). Calcitonin gene-related peptide, a peptide present in spinal cord motoneurons, increases the number of acetylcholine receptors in primary cultures of chick embryo myotubes. Neurosci. Lett. 71: 59-65.Fontaine B., Klarsfeld A., Changeux J.-P. (1987). Calcitonin-gene related peptide and muscle activity regulate acetylcholine receptor alpha-subunit mRNA levels by distinct intracellular pathways. J. Cell Biol. 105: 1337-1342.Laufer R., and Changeux J.-P. (1987). Calcitonin gene-related peptide elevates cyclic AMP levels in chick skeletal muscle : possible neurotrophic role for a coexisting neuronal messenger. EMBO J. 6: 901-906. and the ARIA (heregulin) activating tyrosine kinase cascades.Altiok N., Bessereau J.-L., Changeux J.-P. (1995). ErB3 and ErbB2/neu mediate the effect of heregulin on acetylcholine receptor gene expression in muscle : differential expression at the endplate. EMBO J. 14: 4258-4266.Schaeffer L., Duclert N., Huchet-Dymanus M., Changeux J.-P. (1998). Implication of a multisubunit Ets related transcription factor in synaptic expression of the nicotinic acetylcholine receptor. EMBO J., 17: 3078-3090. The 1990s saw the progressive shift of interest of Changeux from the neuromuscular junction to the nicotinic receptors expressed in the brain. Among the notable achievements of the group is the discovery that neuronal nicotinic receptors are highly permeable to calciumMulle C., Choquet D., Korn H., Changeux J.-P. (1992). Calcium influx through nicotinic receptor in rat central neurons : Its relevance to cellular regulation. Neuron 8: 135-143. – which explains the positive effect of nicotinic receptors on the release of many neurotransmitters in the brain.Léna C, Changeux, JP (1997). Role of Ca2+ ions in nicotinic facilitation of GABA release in mouse thalamus. J Neurosci 17: 576-585. The group also discovered that the nicotinic receptor is regulated by a variety of "allosteric modulators" such as: 1. calcium ionsMulle C., Léna C., Changeux J.-P. (1992). Potentiation of nicotinic receptor response by external calcium in rat central neurons. Neuron 8: 937-945. (This was also discovered independently by the group of John DaniVernino S, Amador M, Leutje CW, Patrick J, and Dani JA (1992) Calcium modulation and high calcium permeability of neuronal nicotinic acetylcholine receptors. Neuron 8: 127-134), which binding sites were later identifiedLe Novère N., Grutter T., Changeux J.-P. (2002). Models of the extracellular domain of the nicotinic receptors and of agonist and Ca++ binding sites. Proc. Natl. Acad. Sci. USA, 99: 3210-3215.Galzi J.-L., Bertrand S., Corringer P.-J., Changeux J.-P., Bertrand D. (1996). Identification of calcium binding sites that regulate potentiation of a neuronal nicotinic acetylcholine receptor. EMBO J. 15: 5824-5832. and localized in the extracellular domain, at the interface between subunits (Le Novère et al. 2002); 2. ivermectin which behaves as a potent positive allosteric modulator binding to a site present in the transmembrane domain (where general anesthetics also bindNury H., Van Renterghem C., Weng Y., Tran A., Baaden M., Dufresne V., Changeux J.-P., Sonner J.M., Delarue M., Corringer P.-J. (2011) X-ray structures of general anaesthetics bound to a pentameric ligand-gated ion channel. Nature 469(7330):428-431); 3. phosphorylation of the cytoplasmic domainTeichberg V.I., Sobel A., Changeux J.-P. (1977) In vitro phosphorylation of the acetylcholine receptor. Nature 267(5611):540-542 which regulate desensitization. By the mid-1990s, Changeux concentrated most of his interest on the function of nicotinic receptors in the basal ganglia and in particular the mesencephalic dopaminergic system. Using mice deleted for nicotinic receptor genes, the group characterised the types of receptor subunits present in the dopaminergic cellsLe Novère N., Zoli M., Changeux J.-P. (1996). Neuronal nicotinic receptor a6 subunit mRNA is selectively concentrated in catecholaminergic nuclei of the rat brain. Eur J Neurosci 8: 2428-2439Klink R., de Kerchove d'Exaerde A., Zoli M., Changeux J.-P. (2001). Molecular and Physiological Diversity of Nicotinic Acetylcholine Receptors in the Midbrain Dopaminergic Nuclei. J. Neurosci. 21: 1452-1463.Champtiaux N, Gotti C, Cordero-Erausquin M, David DJ, Przybylski C, Lena C, Clementi F, Moretti M, Rossi FM, Le Novere N, McIntosh JM, Gardier AM, Changeux JP (2003) Subunit composition of functional nicotinic receptors in dopaminergic neurons investigated with knock-out mice. J Neurosci., 2003 Aug 27;23(21):7820-9. and identified the receptors mainly responsible of the dependence to nicotine, formed by the subunits α4, α6 and β2.Picciotto M.R., Zoli M., Rimondini R., Léna C., Marubio L., Merlo Pich E., Fuxe K., Changeux J.-P. (1998). Acetylcholine receptors containing the b2-subunit are involved in the reinforcing properties of nicotine. Nature 391: 173-177 (1998).Maskos U., Molles B.E, Pons S., Besson M., Guiard B.P., Guilloux J.P., Evrard A., Cazala P., Cormier A., Mameli-Engvall M., Dufour N., Cloz-Tayarani I., Bemelmans A.-P., Mallet J., Gardier A.M., David V., Faure P., Granon S. and Changeux J.-P. (2005) Nicotine reinforcement and cognition restored by targeted expression of nicotinic receptors. Nature 436: 103-107


Modeling cognition

From the mid-1990s, Changeux developed an activity of computational modeling in order to investigate the neuronal bases of cognitive functions. This research was mainly performed in collaboration with
Stanislas Dehaene Stanislas Dehaene (born May 12, 1965) is a French author and cognitive neuroscientist whose research centers on a number of topics, including numerical cognition, the neural basis of reading and the neural correlates of consciousness. As of 201 ...
, now leading th
INSERM-CEA Cognitive Neuroimaging Unit
They notably modeled the acquisition of song recognition in birdsDehaene S., Changeux J.-P., Nadal J.P. (1987). Neural networks that learn temporal sequences by selection. Proc. Natl. Acad. Sci. USA 84: 2727-2731. and the development of numerical abilities.Dehaene S., Changeux J.-P. (1993). Development of elementary numerical abilities : a neuronal model. J. Cognitive Neurosci 5: 390-407. More recently, Dehaene and Changeux developed a neuronal model for access to consciousness based on a brain-wide recruitment of networks of neurons with long-range axons, referred to as the global neuronal workspace.Dehaene S., Kerszberg M., Changeux J.-P. (1998). A neuronal model of a global workspace in effortful cognitive tasks. Proc Natl Acad Sci USA 95: 14529-14534.Dehaene S., Sergent C., Changeux J.-P. (2003) A neuronal network model linking subjective reports and objective physiological data during conscious perception. Proc. Natl. Acad. Sci. USA, 100: 8520-8525. The model might have clinical applications for instance for understanding the mechanism of coma, the action of general anestheticsChangeux J.-P. (2012) Conscious processing: implications for general anesthesia. Curr. Opin. Anesthesiol. 25:397–404. or drug addictionChangeux J.-P., Lou H.C. (2011) Emergent pharmacology of conscious experience: new perspectives in substance addiction. FASEB J. 25(7):2098-2108.


Professional and non-scientific activities

The publication of his book ''Neuronal Man: The Biology of The Mind'' in 1985 brought Changeux celebrity status to the wider public. Since then, he authored or co-authored several other books inspired by his teaching at the College de France: notably, ''Conversations on Mind Matter and Mathematics'' with the mathematician Alain Connes (1998), ''What Makes Us Think'' with the philosopher Paul Ricoeur (2002) and ''the Physiology of truth'' (2002) that are acknowledged as having initiated an instructive dialogue between the two often-hostile disciplines of neuroscience and philosophy. He has also been concerned by the relationships between aesthetic experience and the brain in ''Raison & Plaisir'' (1994), ''The true the good the beautiful: a neurobiological approach'' (2012) and recently ''Les neurones enchantés''. (2014) where he debates the issue of artistic creation with the music composers Pierre Boulez and Philippe Manoury. Changeux received the Lewis Thomas Prize for Writing about Science, Rockefeller University, New-York, 2005. Changeux has also been the curator of three major exhibitions on Art and Science: De Nicolo dell'Abate à Nicolas Poussin: aux sources du Classicisme 1550-1650 Musée Bossuet Meaux in 1988, L'Âme au Corps, Arts et Sciences, 1793-1993 (with Gérard Régnier) Galeries nationales du Grand Palais Paris in 1993-1994 and La lumière au siècle des Lumières et aujourd'hui. Art et science : de la biologie de la vision à une nouvelle conception du monde Galeries Poirel Nancy in 2005. Changeux has also chaired the inter-ministry commission for the conservation of the French artistic heritage since 1989, and has been member of the scientific council of the International Agency of museums since 2007. Last, throughout his career, Changeux has been concerned by the ethical consequences for the city and for the society in general of the recent progress in the Neuroscience. Changeux has headed the National Advisory Committee on Bioethics in France from 1992 to 1998. He organised a scientific conference on the topic, that led to a book he edited, ''fondements naturel de l'ethique''. He is presently the co-chairman of the Ethics and Society division of the European Human Brain Program (since 2013). He is also on the Board of Scientific Governors of The
Scripps Research Institute Scripps Research, previously known as The Scripps Research Institute (TSRI), is a nonprofit American medical research facility that focuses on research and education in the biomedical sciences. Headquartered in San Diego, California, the institu ...
, an independent non-for profit institute focusing on biomedical research.


Public recognition


Main scientific prizes and awards

* 1978: Gairdner Foundation International Award * 1982: Wolf Foundation Prize in Medicine * 1982:
Richard Lounsbery Award The Richard Lounsbery Award is given to American and French scientists, 45 years or younger, in recognition of "extraordinary scientific achievement in biology and medicine." The Award alternates between French and American scientists, and is aw ...
of the US Academy of Sciences and the French Academy of Sciences * 1991: Carl-Gustav-Bernhard medal of the
Swedish Academy of Science The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for prom ...
* 1992: CNRS Gold medal. * 1993:
Louis-Jeantet Prize for Medicine Established in 1986, the Louis-Jeantet Prizes are funded by the ''Fondation Louis-Jeantet'' and awarded each year to experienced researchers who have distinguished themselves in the field of biomedical research in one of the member states of t ...
* 1994: Goodman and Gilman Award in drug receptor pharmacology * 1995:
Max Delbrück Medal The Max Delbrück Medal has been awarded annually from 1992 to 2013 by the Max Delbrück Center for Molecular Medicine (German: ''Max-Delbrück-Centrum für Molekulare Medizin'' or MDC). Named after the German biophysicist Max Delbrück, it is pre ...
* 1998: Prize Emanuel Merck in Chemistry, Darmstadt * 2001:
Balzan Prize The International Balzan Prize Foundation awards four annual monetary prizes to people or organizations who have made outstanding achievements in the fields of humanities, natural sciences, culture, as well as for endeavours for peace and the br ...
for Cognitive Neurosciences * 2002: American Philosophical Society's
Karl Spencer Lashley Award The Karl Spencer Lashley Award is awarded by The American Philosophical Society as a recognition of research on the integrative neuroscience of behavior. The award was established in 1957 by a gift from Dr. Karl Spencer Lashley. Recipients * 202 ...
in neuroscience * 2005:
Lewis Thomas Prize The Lewis Thomas Prize for Writing about Science, named for its first recipient, Lewis Thomas, is an annual literary prize awarded by The Rockefeller University to scientists or physicians deemed to have accomplished a significant literary achieveme ...
for Writing about Science * 2005:
Golden Eurydice Award The Golden Eurydice Award is presented for an outstanding contribution, or contributions over a period, in the field of biophilosophy. It is awarded by the International Forum for Biophilosophy which was established in Belgium by royal decree in 1 ...
* 2007:
NAS Award in the Neurosciences The NAS Award in the Neurosciences is awarded by the U.S. National Academy of Sciences "in recognition of extraordinary contributions to progress in the fields of neuroscience, including neurochemistry, neurophysiology, neuropharmacology, developm ...
from the
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
* 2012: Japanese Society for the Promotion of Science (JSPS) award for eminent scientists * 2016: International research award from the
Olav Thon Foundation The Olav Thon Foundation ( no, Olav Thon Stiftelsen) is a Norwegian foundation and as such the biggest in Norway. Information In accordance with its statutes, the Olav Thon Foundation's primary activity is to own the Olav Thon Group, including ...
(Oslo) * 2018:
Albert Einstein World Award of Science The Albert Einstein World Award for Science is an annual award given by the World Cultural Council "as a means of recognition and encouragement for scientific and technological research and development", with special consideration for researches ...
conferred by the
World Cultural Council The World Cultural Council is an international organization whose goals are to promote cultural values, goodwill and philanthropy among individuals. The organization founded in 1981 and based in Mexico, has held a yearly award ceremony since 198 ...
* 2018: Goldman-Rakic Prize for Outstanding Achievement in Cognitive Neuroscience


Academic memberships and honorary degrees

Deutsche Akademie der Naturforscher Leopoldina zu Halle (Pharmacology), 1974 ; Académie de Médecine de Turin, 1976 ;
National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...
, Washington (US) (foreign associate), 1983 ; Royal Academy of Sciences, Stockholm, (Sweden) (foreign member), 1985 ; Académie des Sciences, Paris, 1988 ; Académie Royale de Médecine de Belgique (Bruxelles) (foreign honorary member), 1988 ;
Academia Europaea The Academia Europaea is a pan-European Academy of Humanities, Letters, Law, and Sciences. The Academia was founded in 1988 as a functioning Europe-wide Academy that encompasses all fields of scholarly inquiry. It acts as co-ordinator of Europea ...
(founding member), 1988 ;
American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...
, Boston, (US) (foreign member), 1994 ; Romanian Academy of Medical Sciences, Bucarest (foreign member), 1996 ; Institute of Medicine of the National Academies, Washington, (US) (foreign associate), 2000 ; Istituto Veneto di Scienze, Lettere Ed Arti, Venezia (Italy), 2001 ; Hungarian Academy of Sciences, Budapest (foreign member associate), 2004 ; European Academy of Sciences, Bruxelles (member), 2004 ; International Academy of Humanism; Académie Royale des Sciences, des Lettres & des Beaux-Arts de Belgique (foreign member), 2010; Accademia Nazionale dei Lincei, Rome, (Italy) (foreign member), 2010. Doctor honoris causa : Universities of Torino, Italy, 1989 ; Dundee, Scotland, 1992 ; Geneva, Switzerland, 1994 ; Stockholm, Sweden, 1994 ; Liège, Belgium, 1996 ; Ecole Polytechnique Fédérale of Lausanne, Switzerland, 1996 ; University of Southern California, Los Angeles, US, 1997 ; Bath, UK, 1997 ; Montréal University, Canada, 2000 ; The Hebrew University of Jerusalem, Israel, 2004 ; Ohio State University, Columbus, US, 2007; University of Buenos Aires, Argentina, 2010. Honorary member of Neurosciences Research Program, MIT and Rockefeller University (US), since 1984; Honorary member of the Japanese Biochemical Society, Sendai, Japan, 1985 ; Honorary member of the American Neurology Association, 1988 ; Honorary member of University College London, 1990 ; Membre d'honneur à titre étranger de la Société Belge de Neurologie, Bruxelles, 1991 ; Member of European Molecular Biology Organization.


Non-scientific honors

Grand Croix dans l'Ordre de la Légion d'Honneur, 2010; Grand-Croix dans l'Ordre National du Mérite 1995 ; Commandeur dans l'Ordre des Arts et des Lettres, 1994.


Scientific publications of historical significance

* (in which Jacques Monod, Jeffries Wyman and Jean-Pierre Changeux presented the concerted model of allosteric transitions, that explained the cooperativity exhibited by many allosteric proteins, such as hemoglobin) *Changeux J.-P., Kasai M., Huchet M., Meunier J.-C. (1970). Extraction à partir du tissu électrique de gymnote d'une protéine présentant plusieurs propriétés caractéristiques du récepteur physiologique de l'acétylcholine. C. R. Acad. Sci. 270D: 2864–2867. (the first purification of a neurotransmitter receptor. Since the article is in French, most people quote the description of the toxin that allowed the receptor to be identified: * (In which the authors develop a formal model of synapse selection, precursor of the "neural darwinism". This is the original work, although most people quote the subsequent review etter suited to a non-specialist audience and presenting the biological context Changeux JP, Danchin A (1976) Nature, 264 (1976) 705–712.)


Books by Jean-Pierre Changeux

* Changeux, Jean-Pierre. (2008) ''Du vrai, du beau, du bien : Une nouvelle approche neuronale'' * Changeux, Jean-Pierre; Stuart Edelstein. (2004) ''Nicotinic Acetylcholine Receptors: From Molecular Biology to Cognition'' * Changeux, Jean-Pierre. (2002) ''L'homme de verite'' (2004 ''The physiology of truth'') * Changeux, Jean-Pierre;
Paul RicÅ“ur Jean Paul Gustave RicÅ“ur (; ; 27 February 1913 â€“ 20 May 2005) was a French philosopher best known for combining phenomenological description with hermeneutics. As such, his thought is within the same tradition as other major hermeneutic ...
. (1998) ''Ce qui nous fait penser'' (2002 ''What Makes Us Think. A Neuroscientist and a Philosopher Argue About Ethics, Human Nature, and the Brain''Review of ''What Makes Us Think'' by Elliott White
) * Changeux, Jean-Pierre. (1994) ''Raison et plaisir'' * Changeux, Jean-Pierre;
Alain Connes Alain Connes (; born 1 April 1947) is a French mathematician, and a theoretical physicist, known for his contributions to the study of operator algebras and noncommutative geometry. He is a professor at the , , Ohio State University and Vande ...
. (1989) ''Matière à pensée'' (1995 ''Conversations on Mind, Matter and Mathematics'') * Changeux, Jean-Pierre. (1983) ''L'homme neuronal'' (1985 ''Neuronal Man: The Biology of Mind'')


References


External links

*
Jean-Pierre Changeux's laboratory in 2005Jean-Pierre Changeux
International Balzan Prize Foundation {{DEFAULTSORT:Changeux, Jean-Pierre 1936 births Living people Albert Einstein World Award of Science Laureates Richard-Lounsbery Award laureates People from Domont French neuroscientists French biologists French geneticists École Normale Supérieure alumni Collège de France faculty Columbia University faculty Foreign associates of the National Academy of Sciences Members of the French Academy of Sciences Members of the Royal Swedish Academy of Sciences Wolf Prize in Medicine laureates Winners of the Prix Broquette-Gonin (literature) Members of the National Academy of Medicine