The neurophysiological aspects of Pavlov's theory of higher nervous activity: in honor of the 150th anniversary of Pavlov's birth

Whereas Ivan P. Pavlov (1849-1936) is well-known for his work on classical conditioning, his contribution to neuroscience, particularly his interest in the function of neural centers in the central nervous system, is not as widely known. During the last three decades of his life, Pavlov explored cortical processes by salivary reflex conditioning, a method he used to develop his theory of higher nervous activity. This theory outlined the function of the brain in higher organisms in their interaction with the changing environmental contingencies. As early as 1908, Pavlov outlined a neurophysiological theory as the physiological basis of his theory of higher nervous activity. He maintained that the neural processes of excitation and inhibition irradiate and concentrate among the cortical neural centers. Most of all, he emphasized the plasticity of the cortex in higher organisms' in the Darwinian struggle for existence.     

The Neurophysiological Aspects of Pavlov’s Theory of Higher Nervous Activity: In Honor of the 150th Anniversary of Pavlov’s Birth

Whereas Ivan P. Pavlov (1849-1936) is well-known for his work on classical conditioning, his contribution to neuroscience, particularly his interest in the function of neural centers in the central nervous system, is not as widely known. During the last three decades of his life, Pavlov explored cortical processes by salivary reflex conditioning, a method he used to develop his theory of higher nervous activity. This theory outlined the function of the brain in higher organisms in their interaction with the changing environmental contingencies. As early as 1908, Pavlov outlined a neurophysiological theory as the physiological basis of his theory of higher nervous activity. He maintained that the neural processes of excitation and inhibition irradiate and concentrate among the cortical neural centers. Most of all, he emphasized the plasticity of the cortex in higher organisms’ in the Darwinian struggle for existence.     

Thomas Laycock and a trophic nervous system

A short introduction is given to Thomas Laycock (1812-1876), and attention drawn to the development of neurological understanding in the nineteenth century. The main text describes a postulated part of the nervous system, the trophic, which was thought to govern nutritive functions of the body. Thomas Laycock appears as a lone figure in British medicine in giving serious consideration to a trophic nervous system. His discussions are based on clinical observations but his theories are speculative. He devised an instrument (an aesthesiometer) which he hoped would identify abnormalities of the trophic nervous system. The demise of a trophic nervous system is described with quotations from Charcot and Gowers and the use of the word trophic in current practice is mentioned.     

Henry Herbert Donaldson’s (1857–1938) contribution to an organized approach to the experimental study of the mammalian central nervous system

ABSTRACT

This article shows that the academic and research careers of Henry Herbert Donaldson (1857–1938) were directed to provide basic information about the growth of the vertebrate nervous system and to provide standards and the means to make such research efficient. He earned the reputation of making the albino rat a standard laboratory animal. His academic career began when he was an undergraduate at Yale University in 1875 and concluded with his death as Professor and Head of the Department of Neurology at the Wistar Institute of Anatomy and Biology of the University of Pennsylvania in 1938. During that period, pivotal experiences occurred, including research in physiological chemistry with Chittenden at the Sheffield School at Yale, graduate study at Johns Hopkins University, postgraduate study in Europe, and professorial positions at Clark University and the University of Chicago. It was at Johns Hopkins University that Donaldson learned about the need for physiological, anatomical, and psychophysical research and about the techniques to allow such research. It was at Clark University that he had first-hand and detailed experience with the anatomy of the brain of a deaf-blind-mute woman, as he attempted to correlate her sensory deficits with her brain development. It was at Clark University that he clearly recognized the need for standardization in neurological research. At the University of Chicago, he developed administrative skills and began a coordinated research effort to delimit the growth of the nervous system. It was at Chicago that he learned that the albino rat could be a reasonable subject for such research. It was also at Chicago that he was able to formulate ideas about the future organizational needs of human neuroanatomy. It was at the Wistar Institute that his research program and his professional career matured. He organized a research effort to elucidate the growth of the nervous system. He contributed to the coordination of neurological research in the United States and Europe. It was while at the Wistar Institute that he became well-known for making the albino rat a standard laboratory mammal—a convenient living material for research.     

The impossible interview with the man of the neuron doctrine. Interview by Edward G Jones

This paper follows the form of that by Mazzarello that precedes it (Mazzarello, 2006) and presents an imaginary interview with Santiago Ramón y Cajal in December 1906. A few days earlier Cajal had been awarded the Nobel Prize for Physiology or Medicine, an award that he shared equally with Professor Camillo Golgi. Golgi had been recognized for his work as a pioneer into investigations of the nervous system, primarily on account of his discovery of the "black reaction" of silver chromate impregnation of whole nerve cells and their processes. Cajal had been recognized for his implementation of that method and for laying with it the foundations of what was to become modern neuroanatomical science. Paradoxically, the two awardees had been led by their researches to diametrically opposed views of the organization of the nervous system. Golgi believed in a continuous network of axons that formed the basis of all the integrative properties of the nervous system, while Cajal had provided the information that led to the formulation of the neuron doctrine that saw the nervous system as being made up of chains of discontinuous cells joined by polarized functional contacts that we now call synapses. The paper takes the form of an interview with Professor Cajal in the Grand Hotel Stockholm. His responses to questions posed by the imaginary interviewer are all taken from Cajal's own writings.     

Louis Muskens: a leading figure in the history of Dutch and world epileptology

In the history of Dutch neurology Muskens has a place in his own right. Elderly neurologists still attest to the special fame of Muskens. He held a strong opinion on developing the specialty of neurology independent of psychiatry. At the same time he maintained that surgery of the nervous system also should be included in the realm of neurology. These views met with considerable opposition from colleagues and led to Muskens' isolation. To the field of epileptology he contributed both clinical and experimental neurological studies. With Donath he was the co-founder of the International League Against Epilepsy in 1909. In addition he held a lifelong interest in the pathophysiology of forced movements, which he studied both in human pathology and in experimental studies throughout the vertebrate series. This resulted in his magnum opus on the supravestibular system in 1935. His scientific work was well received in scientific societies all over Europe.     

Louis Muskens: A Leading Figure in the History of Dutch and World Epileptology

In the history of Dutch neurology Muskens has a place in his own right. Elderly neurologists still attest to the special fame of Muskens. He held a strong opinion on developing the specialty of neurology independent of psychiatry. At the same time he maintained that surgery of the nervous system also should be included in the realm of neurology. These views met with considerable opposition from colleagues and led to Muskens’ isolation. To the field of epileptology he contributed both clinical and experimental neurological studies. With Donath he was the co-founder of the International League Against Epilepsy in 1909. In addition he held a lifelong interest in the pathophysiology of forced movements, which he studied both in human pathology and in experimental studies throughout the vertebrate series. This resulted in his magnum opus on the supravestibular system in 1935. His scientific work was well received in scientific societies all over Europe.     

From the Mind to the Brain: An Unusual Pathway

One of the most unrecognized aspects of Golgi's life was his deep interest in neuropsychiatry. From 1865 to 1868 he attended the Clinica per le Malattie Nervose e Mentali in Pavia directed by Cesare Lombroso, the founder of modern criminology. Golgi was involved in research on the etiology of psychiatric ailments. During this short period of time he produced significant theoretic advances in clinical psychiatry. However, very soon he started to criticize the conceptual approach as well as the nosological system proposed by his academic mentor. In July 1868 he left Lombroso's school in search for a more rational method of studying brain functions and diseases. In spite of his anatomical approach to the central nervous system, he always maintained curiosity in the phenomenology of functional and organic mental disorders. This predisposition is witnessed by his capability to relate clinical observations to neuropathological findings.     

From the mind to the brain: an unusual pathway

One of the most unrecognized aspects of Golgi's life was his deep interest in neuropsychiatry. From 1865 to 1868 he attended the Clinica per le Malattie Nervose e Mentali in Pavia directed by Cesare Lombroso, the founder of modern criminology. Golgi was involved in research on the etiology of psychiatric ailments. During this short period of time he produced significant theoretic advances in clinical psychiatry. However, very soon he started to criticize the conceptual approach as well as the nosological system proposed by his academic mentor. In July 1868 he left Lombroso's school in search for a more rational method of studying brain functions and diseases. In spite of his anatomical approach to the central nervous system, he always maintained curiosity in the phenomenology of functional and organic mental disorders. This predisposition is witnessed by his capability to relate clinical observations to neuropathological findings.     

The role of Herman Hoppe of Cincinnati in the initial clinical recognition of myasthenia gravis

One of the earliest papers describing a case of what came to be known as myasthenia gravis was written in 1892 in the German language by an American, Herman Hoppe, who at the time was an assistant in the Berlin polyclinic of the prominent German neurologist. Hermann Oppenheim. At Oppenheim's instigation, Hoppe published the pathology of a case that Oppenheim had diagnosed during life; he collected all the reported similar cases and tried to establish a symptom-complex, for which he was given credit in Oppenheim's great neurology textbook of 1894. Upon his return to Cincinnati, Ohio, Hoppe's European experience qualified him as a specialist in nervous and mental diseases. His private practice of "neuropsychiatry" was his main occupation, but he also volunteered to teach as Professor of Nervous and Mental Diseases at the University of Cincinnati. In 1901 Oppenheim published the first monograph about what he called "Die Myasthenische Paralyse (Bulbarparalyse ohne anatomischen Befund)", summarizing 60 cases described in the medical literature up to that time. Hoppe, on the other hand, wrote on myasthenia gravis only once again, a review article in 1914 in a Cincinnati weekly, giving Oppenheim credit for the establishment of the disease as a clinical entity.     

The origin of the term plasticity in the neurosciences: Ernesto Lugaro and chemical synaptic transmission

The Italian psychiatrist Ernesto Lugaro can be regarded as responsible for introducing the term plasticity into the neurosciences as early as 1906. By this term he meant that throughout life the anatomo-functional relations between neurons can change in an adaptive fashion to enable psychic maturation, learning, and even functional recovery after brain damage. Lugaro's concept of plasticity was strongly inspired by a neural hypothesis of learning and memory put forward in 1893 by his teacher Eugenio Tanzi. Tanzi postulated that practice and experience promote neuronal growth and shorten the minute spatial gaps between functionally associated neurons, thus facilitating their interactions. In addition to discovering the cerebellar cells known by his name and advancing profound speculations about the functions of the glia, Lugaro lucidly foresaw the chemical nature of synaptic transmission in the central nervous system, and was the first to propose the usage of the terms "nervous conduction" and "nervous transmission" in their currently accepted meaning.     

The Origin of the Term Plasticity in the Neurosciences: Ernesto Lugaro and Chemical Synaptic Transmission

The Italian psychiatrist Ernesto Lugaro can be regarded as responsible for introducing the term plasticity into the neurosciences as early as 1906. By this term he meant that throughout life the anatomo-functional relations between neurons can change in an adaptive fashion to enable psychic maturation, learning, and even functional recovery after brain damage. Lugaro’s concept of plasticity was strongly inspired by a neural hypothesis of learning and memory put forward in 1893 by his teacher Eugenio Tanzi. Tanzi postulated that practice and experience promote neuronal growth and shorten the minute spatial gaps between functionally associated neurons, thus facilitating their interactions. In addition to discovering the cerebellar cells known by his name and advancing profound speculations about the functions of the glia, Lugaro lucidly foresaw the chemical nature of Synaptic transmission in the central nervous system, and was the first to propose the usage of the terms “nervous conduction” and “nervous transmission” in their currently accepted meaning.     

Some aspects of the history of the law of dynamic polarization of the neuron. From William James to Sherrington, from Cajal and van Gehuchten to Golgi

William James was the first to suggest that propagation of impulses in the nervous system proceeds in one direction, from sensory to motor neurons, but not viceversa. His law of forward direction preceded the formulation of the law of dynamic polarization of van Gehuchten and Cajal, which assumed that nerve impulses are conducted cellulipetally along dendrites and cellulifugally along axons, based on different anatomo-functional properties of these neuronal components. Golgi did not accept the law of dynamic polarization because he believed that dendrites are involved in the nutrition of the neuron rather than in impulse propagation, and that impulses can travel in any direction in the axonal components of the diffuse nerve network. Sherrington in turn experimentally demonstrated that intraneuronic conduction is reversible, whereas, in accord with James's law, propagation of impulses along neuronal chains is irreversible, due to the valve-like action of synapses. The story of the law of dynamic polarization shows that neither Golgi nor Cajal paid much heed to Sherrington's findings and to neurophysiological studies in general, probably because they felt that histology alone could provide the key for understanding the general functioning of the nervous system. It is argued here that this attitude was detrimental to the progress of the neurosciences, because a multidisciplinary approach based on different techniques is inevitably called for in order to develop a plausible theory of the nervous system.     

The Role of Herman Hoppe of Cincinnati in the Initial Clinical Recognition of Myasthenia Gravis

One of the earliest papers describing a case of what came to be known as myasthenia gravis was written in 1892 in the German language by an American, Herman Hoppe, who at the time was an assistant in the Berlin polyclinic of the prominent German neurologist, Hermann Oppenheim. At Oppenheim’s instigation, Hoppe published the pathology of a case that Oppenheim had diagnosed during life; he collected all the reported similar cases and tried to establish a symptom-complex, for which he was given credit in Oppenheim’s great neurology textbook of 1894. Upon his return to Cincinnati, Ohio, Hoppe’s European experience qualified him as a specialist in nervous and mental diseases. His private practice of “neuropsychiatry” was his main occupation, but he also volunteered to teach as Professor of Nervous and Mental Diseases at the University of Cincinnati. In 1901 Oppenheim published the first monograph about what he called “ Die Myasthenische Paralyse (Bulbarparalyse ohne anatomischen Befund) ”, summarizing 60 cases described in the medical literature up to that time. Hoppe, on the other hand, wrote on myasthenia gravis only once again, a review article in 1914 in a Cincinnati weekly, giving Oppenheim credit for the establishment of the disease as a clinical entity.