History of neuroscience and research into neuroglia

Alexei VerkhratskyThe University of Manchester, UK

1

“If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down”Charles Darwin (1809 – 1882)The Origin of Species

“All things in life are so multifaceted, contradictory and obscure that we can never be sure about the truth”.Desiderius Erasmus (1466 – 1536)Moriae encomium (The Praise of Folly)

2

Localisation of brain functions

3 Where the thoughts dwell

Cardiocentric doctrine:Egyptians,Hebrews,Aristotle,Survived into MiddleAges

Ventricular-pneumatic doctrinePythagoras, Plato, HippocratesHerophilius and ErasistratusGalenLeonardo da Vinci, Andreas Vesalius

From: Gregor Reisch Margarita philosophica (The Pearl of Wisdom); first edition 1503

From: Leonardo Da Vinci “Codices”

4

Where the thoughts dwell - "Cogito Ergo Sum" ("I think, therefore I am.")

Marcello Malpighi1628 - 1694

Epistolae de Cerebro et cortices Cerebri ad Fracassatum, 1687

Thomas Willis 1621-1675

Cerebri Anatome, 1664

Rene Descartes 1596-1650

Traite de l'homme,1664

The brain grey matter is considereda substrate for cognitive function

The concept of reflex andThe brain as a machine

5Cortical localisation of functions

Franz Joseph Gall1758 - 1828

Phrenological chart from Samuel Wells

Postulates of phrenology:1. The brain is the organ of cognitionand2. Every faculty and function has a specific localisation within the brain matter

6

Cellular theory and visualisation of neural cells

7 Cortical localisation of functions: Mapping of the brain

Luigi Rolando (1773 – 1831)First electrical stimulation of the brain surface

Eduard Hitzig (1838-1907) and Gustav Theodor Fritsch (1838 – 1927) performed the first mapping of the motorcortex of the dog (1870)

Electrophysiological maps of the brain produced by David Ferrier (1843 – 1928)

Motor cortical representations (“homunculus”) of Wilder Penfield (1891 – 1976)

8

“Omnis cellula e cellula” - The cellular theory

First images of moving spermatozoids from humans, rabbits and dogs were drawn by Antonius van Leeuwenhoek

Theodor Schwann, (1810-1882) Matthias Jakob Schleiden (1814 - 1881)

The theory was formalised at the beginning of 19 centuryby Schleiden and Schwann

First microscope was built in Holland in 1595 by Hans and

Zacharias Jansen

Robert Hooke image of a thin cutting of cork, where he discovered empty spaces contained by walls which he termed cells.

9 First images of neural cells 10

Camillo Golgi opens the brain: Development of “reazione nero”(black staining reaction)

Golgi, C. (1873). Sulla struttura della sostanza grigia del cervello. Gazzetta Medica Italiana, Lombardia, 33, 244–246;Golgi, C. (1875): Sulla fina struttura dei bulbi olfactorii. Rivista Sperimentale di Freniatria e Medicina Legale 1, 405–425;Golgi, C. (1903): Opera Omnia. Milano: Hoepli.

Olfactory bulb

Hippocampus

Cerebellum

11 Neuronismo o reticularismo: Clash of the TitansDecember 10 - 13, the 1906, Royal Academy of Music, Stockholm

This means that in the nervoussystem there exists a diffuseneural net throughout the greymatter…

The collateral and terminalbranches of every axon end in thegray matter, not in a diffuse networkas maintained by Gerlach andGolgi, but in free arborizationsarranged in a variety of forms

Reticularismo Neuronismo

12

Neuronismo o reticularismo: Clash of the TitansDecember 10 - 13, the 1906, Royal Academy of Music, Stockholm

This means that in the nervoussystem there exists a diffuseneural net throughout the greymatter…

The collateral and terminalbranches of every axon end in thegray matter, not in a diffuse networkas maintained by Gerlach andGolgi, but in free arborizationsarranged in a variety of forms

Reticularismo Neuronismo

13

I am deeply convinced that such divergences, by spurring research, are always beneficial toscience. I hold Ramón y Cajal in the greatest consideration. Not only do I admire his productivity andcreativity but I also appreciate the importance of his original findings … (Golgi, 1891). During mylecture I have only expressed my different views that are now supported by new research onneurofibrils … However, it would have been better if, also on this occasion, I had followed myancient favoured aphorism “one never regret having been silent; only having spoken!”

Camillo Golgi

I have always rendered Professor Golgi the tribute of my admiration and in all my books you canread my enthusiastic praises of this savant of Pavia. I had the right, then, to expect equally friendlytreatment on the occasion of his lecture on Monday. In defending his extravagant lucubrations,which might have been permitted 20 years ago when the nature of inter neuronal connections wasunknown, he made a display of pride and self-worship so immoderate that it had a deplorableeffect upon the assembly. I have never understood those strange mentalities that are devotedthroughout life to the worship of their own egos, hermetically sealed off from all innovation andimpermeable to the continuous changes taking place in science. What a cruel irony of fate to pair,like Siamese twins joined at the shoulder, scientific adversaries of such contrasting character!

Ramón y Cajal, S (1901): Recuerdos di mi Vida.

Clash of the Titans: The aftermath

Mazzarelo, P (1999): J Hist Neurosci, 15, 318-325Jones, E.G. (1999): J Hist Neurosci, 15, 326-349

14

Bioelectricity: Mechanisms of cellular excitability and neuronal signal propagation

15

JanSwammerdam(1637 – 1680)

Jan Swammedam introduces neuro-muscular preparation in 1660s

Swammerdam J. (1758) The book of nature (Biblia naturae). Seyfert, London

16

And now we might add something concerning a certain mostsubtle spirit which pervades and lies hid in all gross bodies; bythe force and action of which spirit the particles of bodies attractone another at near distances, and cohere, if contiguous; andelectric bodies operate to greater distances, as well repellingas attracting the neighboring corpuscles; and light is emitted,reflected, refracted, inflected, and heats bodies; and allsensation is excited, and the members of animal bodies moveat the command of the will, namely, by the vibrations of thisspirit, mutually propagated along the solid filaments of thenerves, from the outward organs of sense to the brain, andfrom the brain into the muscles. But these are things thatcannot be explained in few words, nor are we furnished with thatsufficiency of experiments which is required to an accuratedetermination and demonstration of the laws by which thiselectric and elastic spirit operates.

Newton, I. (1713). Principia Mathematica (2nd edition). English translation by Andrew Motte, Sir Isaac Newton’s Mathematical Principles of Natural Philosophy and his System of the World(1729, reprinted 1934 by the University of California Press).

Issak Newton as a foreteller of bioelectricity17 Luigi Galvani – Father of electrophysiology

b. Sept. 9, 1737, Bologna, Papal States (Italy) d. Dec. 4, 1798, Bologna, Cisalpine Republic (France)

To explain “animal electricity”, Galvani suggested that nerve and muscle tissues arecapable of generating electricity by accumulating positive and negative charges on twoopposite surfaces. Moreover, the electrical flow necessary to produce voltage changeswas explained by Galvani in terms of specific water-filled pores between the internal andexternal surfaces, this suggestion being the harbinger of ion channels.

18

The critical experiment of Galvani demonstrating propagation of nerve impulse

Luigi Galvani(1737 - 1798)

Lucia Galeazzi(1743 – 1788)

Galvani L. (1794) Dell'uso e dell'attività dell'arco conduttore. S. Tommaso d'Aquino.

19 Giovanni Aldini b. April, 1762, Bologna, Italy d. January 17, 1834, Milan, Italy

The most famous of Aldini’s demonstrations took place atthe Royal College of Surgeons in London in 1803, on ahanged man named George Forster. Anatomical dissectionhad formed part of Forster’s death sentence, but no onecould have visualized quite the violation that Aldini wasgoing to inflict on him. Before a large medical and generalaudience, he took a pair of conducting rods linked to apowerful battery, and touched the rods to various parts ofthe body in turn. The results were dramatic. When the rodswere applied to Forster’s mouth and ear, “the jaw began toquiver, the adjoining muscles were horribly contorted, andthe left eye actually opened.” When one rod was moved totouch the rectum, the whole body convulsed: indeed, themovements were “so much increased as almost to give anappearance of re-animation”.

20

Lord Byron Mary Wollstonecraft(Shelley) Percy Shelley

John Polidoriu

“Hateful day when I received life!” I exclaimed in agony. “Accursed creator! Why did you form a monster so hideous that even you turned against me in disgust?”

“Frankenstein or The Modern Prometheus”

“Did I request Thee, Maker, from my clayTo mould me man? Did I solicit TheeFrom darkness to promote me?”

“Paradise Lost” This verse was used as an epigraph for the first edition of the Frankenstein, 1818

21

Carlo Matteuchi (1811-1865) in Pavia and Florence detected currents in muscle by using a frog nerve as a sensor (1830)

Matteucci C (1842) Deuxième mémoire sur le courant électrique propre de la grénouille et sur celui des animaux à sang chaud. Ann. Chim. Phys 6: 301-339.

22

Emil Du Bois-Reymond (1818-1896) in Berlin measured the nerve and muscle current (1848)

du Bois-Reymond E. (1884) Untersuchungen über thierische elektricität, 1848-1884 (2 bande). Reimer, Berlin.

23 Hermann von Helmholtz (1821-1894) in Berlin measured nerve conduction velocity (1850)

Helmholtz H (1850) Note sur la vitesse de propagation de l’agent nerveux dans les nerfs rachidiens. C. R. Acad. Sci. (Paris) 30: 204-206.

24

Julius Bernstein (1839-1917) in Heidelberg and Halle applied Nernst equation to explain membrane potential (1871)

Bernstein J (1868) Über den zeitlichen Verlauf der negativen Schwankung der Nervenstroms. Pflügers Arch 1:173–207

Differential rheotome

And the first recording of action potential (sampling rate 0.3 ms – sic!)

From: Nilius B. (2003): Pflugers Archiv and the advent of modern electrophysiology. From the first action potential to patch clamp. Pflugers Arch 447: 267-271, 2003.

25 Charles Scott Sherington (1857-1952) in Oxford defined the synapse(1906)

26

Otto Loewi (1873-1961) born in Frankfurt, working in Marburg, Wien and Graz, discovered neurotransmitter (Vagusstoff=acetylcholine) in 1921

27Alan Lloyd Hodgkin, Andrew Fielding Huxley and Berhard Katz develop

ionic theory of excitation

Alan Hodgkin(1914 – 1998)

Andrew Huxley(1917 – 2012)

Bernard Katz(1911 – 2003)

28

Patch-clamp techniqueErwin Neher Bert Sakmann

Neher E, Sakmann B. (1976) Single-channel currents recordedfrom membrane of denervated frog muscle fibres. Nature, 260,799-802.Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ. (1981)Improved patch-clamp techniques for high-resolution currentrecording from cells and cell-free membrane patches. PflugersArch, 391, 85-100.

29

Neuroglia: the birth of the concept

30

Rudolf VIRCHOWÜber das granulierte Ansehen der Wandungen der Gehirnventrikel. Allg. Z. Psychiatrie, 3: 242-250, 1846Die Cellularpathologie in ihrer Begründung auf physiologische and pathologische Gewebelehre. ZwanzigVorlesungen gehalten während der Monate Februar, März und April 1858 im pathologischen Institut zuBerlin. Verlag von August Hirschfeld, Berlin., p. 440, 1858.

The glia was born on April 3rd 1858

“…connective substance, which forms in the brain, in the spinal cord, and in the higher sensory nerves a sort of Nervenkitt (neuroglia), in which the nervous system elements are embedded".

(“γλια” in a form of γλοιοσ appears in Semonides where it refers to “oily sediment” used for takingbaths, in Herodotus, for whom it meant “gum” and, in Aristophanes, who used it in a sense of “slippery,knavish”; never appeared in Homer’s texts.In modern Greek the root remains in word “γλοιωης" which means filthy and morally debased person.Only in after-classic times “glia” became connected with Latin root glu- referring to “glue” (e.g. gluten).

31

A

B

A Numerous connective tissue cells and nuclei, numerous corpora amylacea are also visible which are below shown enlarged; E, epithelium; N, nerve fibers; v vessel)

B Elements of neuroglia from white matter of the human cortex, a free nucli with nucleolus, b, nuclei with partially destroyed cell bodies, c complete cellsFrom Virchow (1858)

First images of glia made by Rudolf Virchow32

A

B

CA Cross section of the retina from frog, a pigment cells, b, rods, c, cones, e, swelling of the radial fiber f, with its conical end ending at the limitans

B Isolated radial fiber from frog

From Müller (1856)

C Müller fiber of the sheep retina inspected with a microscope from Amici. yyy, brush-like fibrils extending from the outer Müller fiber in the outer granular layer; xx internal limiting membrane; a, opening in the limiting membrane; b, very delicate network of fenestrated membranes similar in the ganglion cell layer; cc, network in the so called molecular layer; ddd, nuclei as part of the Müller fibers; ee cavity in which the nuclei or the cells of the internal granular layer are located

From Schultze (1859)

Retinal glial cells (Müller cells) drawn by Heinrich Müller and Max Schulze 33

A

B

C

From the posterior root of the nervus alicujus lumbalis (magnification 200). A, organic fiber; b, c, primitive tubes. At d, the primitive fiber appears unsheathed.

B, Primitive fiber from rabbit cerebellum, 110 magnification; one can recognize the tender sheath and the transparent fiberFrom Remak, 1838

C, Nervous fibers from the ischiadic nerve of rabbit; cy, axon; m, myelin sheath; n, n´, nuclei of the segmentsFrom Ranvier (1875)

Visualisation of myelin sheath by Robert Remak and Louis Antoine Ranvier

(The word myelin was introduced by Rudolf Virchow and means marrow (Greek μυελοσ ), because myelin appearance reminded him of bone

marrow

34

Golgi images of neuroglia (1874)

Astrocytes

Astroglial network

Oligodendrocytes

Astrocytes contact blood vessels

C. Colgi (1903) Opera Omnia

35

A B

A, Supportive cells (astrocytes) from the spinal cord of a 9 month old child, Golgi impregantion

B, Spinal cord of a 14 cm human embryo, Golgi impregnation, with stained supportive cells, left, ependymal scarfold, right, Precursors of spider cells (astroblasts).

Glial networks in the spinal cord 36

Gustaf Magnus Retzius (1842 - 1919) Biologische Untersuchungen(Stockholm: Samson and Wallin, 1890-1914), vol. 6 (1894), plate ii, Fig. 5;Cortex of 45 cm long human embryo)

Gustaf Magnus Retzius and images of glia 37 Spanish School: Images of neuroglia by Santiago Ramon y Cajal and Pio del Rio Hortega

A,B: AstrocytesC: OligodendrocytesD,E: Microglia

38

Astrocytes (literally “star-like cells”): the homeostatic cells of the brain

Von Lenhossek M. (1891) Zur Kenntnis der Neuroglia des menschlichen Ruckenmarkes. Verh Anat Ges 5: 193-221.Von Lenhossek M. (1893). Der feinere Bau des Nervensystems im Lichte neuester Forschung. Berlin: Fischer's Medicinische Buchhandlung H. Kornfield.

Michael von Lenhossek(1863 – 1937)

Protoplasmic astrocytesAndriezen WL. The neuroglia elements of the brain. Br Med J 2: 227-230, 1893.

Fibrous astrocytesKölliker A. Handbuch der Gewebelchre des menschen. Leipzig: Wilhelm

Oligodendrocytes and Schwann cells maintain axonal conductance

Pio del Rio Hortega(1882-1945)

Electron microphotograph of oligodendrocytes.From: http://www.regenecell.com/article-multiple-sclerosis-status.htmOriginal drawing

39 Pio del Rio Hortega (1882 – 1945): Discoverer of microglia

Del Rio-Hortega P (1932) Microglia. In: Cytology and cellular pathology of the nervous system (Penfield W, ed), pp 482-534. New York: Hoeber.

40

The appearance of a neurone

Neurone doctrine: Neuronal processes as the morphological substrate of integration

in the CNS

“Neurone” - term introduced in 1891 byWilhelm Gottfried von Waldeyer (1836 -1921),Deutsche Medizinishe Wochenschaft,1891, v. 44 - 50 (6 papers in total).

“Neuronal doctrine” wasfor the first timeformalised bySigmunt Exner in his book, Entwurf zurphysiologischen Erklärung der psychishenErscheinungen, published in 1894

Neuronal Doctrine

41

Carl Ludwig Schleich (1859–1922)

Neuronal-glial networks according to Carl Schleich

Carl Ludwig Schleich (1859–1922)“der gefallene chirurgische Engel”

founder of the theory of neuronal-glial interactions

Schleich believed that glia and neurones are equalplayers and both are active cellular elements of thebrain. He thought that glial cells represent generalinhibitory mechanism in the brain. He postulated thatneuronal excitation must be transmitted fromneurone to neurone through intercellular gap; andthis inter-neuronal gap filled with glial cells is theanatomical correlate for controlling networkexcitation/inhibition. The glial content of humorrepresents the mechanism of control: swollen glialcell would inhibit neuronal communications, whenglia shrinks, the impulse propagates freely.

C.L.Schleich (1894): Schmerzlose Operationen, 1st Ed

42

Carl Ludwig Schleich (1859–1922)

Neuronal-glial networks according to Carl Schleich

Carl Ludwig Schleich (1859–1922)“der gefallene chirurgische Engel”

founder of the theory of neuronal-glial interactions

43 Astrocytes dynamically control local circulation and informationflow in neuronal networks: Cajal’s model

Ramón y Cajal, S. (1895) Algunas conjeturas sobre el mechanismoanatomico de la ideacion, asociacion y atencion. Imprenta y Libreria de Nicolas Moya; Ramon y Cajal, S. (1925) Contribution a la connaissance de la nevroglia cerebrale et cerebeleuse dans la paralyse generale progressive. Trab. Lab. Invest. Biol. Univ. Madrid 23, 157-216

44

“What is the function of glial cells inneural centers? The answer is stillnot known, and the problem is evenmore serious because it may remainunsolved for many years to comeuntil physiologists find directmethods to attack it.”

S. Ramon y Cajal : Histology of the Nervous System; translated by N. Swanson & L. Swanson, OUP, New York, 1995.

45