The importance of I. P. Pavlov for the development of neuroscience

By his experimental and theoretical work on the physiology and pathophysiology of the higher nervous activity I.P. Pavlov significantly influenced the development of Neuroscience. During the 1950 Pavlovian Conference in Moscow, Stalin and the Communist Party tried to dogmatize his and his pupils’ fundamental theories. But the Pavlovian ideas were developed by his pupils in open discussions with representatives of other schools in a very creative way, opening the doors for a systemic approach to understanding the integrative functional systems of brain and behavior. Pavlov emphasized the high plasticity of the central nervous system investigated the complex functional systems within the brain and between the organism and its environment, and designed models for pathological deviations of the higher nervous activity. During his last years, he freed himself from the strong deterministic view and characterized the organism and its environment as a self-organizing system. Lecture at the Annual Meeting of the Pavlovian Society, November 1, 1998, Dusseldorf, Germany.     

Pavlov as a psychologist

American psychologists are informed on Pavlov’s work on conditional reflexes but not on the full development of his theory of higher nervous activity. This article shows that Pavlov’s theory of higher nervous activity dealt with concepts that concerned contemporary psychologists. Pavlov used the conditioning of the salivary reflex for methodological purposes. Pavlov’s theory of higher nervous activity encompassed overt behavior, neural processes, and the conscious experience. The strong Darwinian element of Pavlov’s theory, with its stress on the higher organisms’ adaptation, is described. With regard to learning, Pavlov, at the end of his scholarly career, proposed that although all learning involves the formation of associations, the organism’s adaptation to the environment is established through conditioning, but the accumulation of knowledge is established by trial and error.     

Schilder and Pavlov's theory of higher nervous activity. A critique and apologia

In the late 1920s, the Viennese psychoanalyst Paul Schilder, after performing a conditioning experiment with human subjects, criticized I. P. Pavlov's concept of "experimental neurosis." Schilder maintained that subjective reports by conditioned human subjects were more informative than the objectively observed behavior of conditioned dogs. In 1932, Pavlov published a rejoinder to Schilder's critique in the Journal of the American Medical Association. Pavlov maintained that Schilder misunderstood the value and implications of the scientific, objective method in the study of experimental neurosis. In 1934, Schilder subjected Pavlov's theory of higher nervous activity to an incisive critique in a 1935 article in Imago. Schilder objected to Pavlov's narrow, reductionist conceptualization of the conditional reflex. Schilder reiterated his view that the psychological, subjective explanation of the conditional reflex is preferable to the physiological, objective explanation, and that the inference of cortical phenomena from experimental findings might be improper. Neither Pavlov nor any of his disciples replied to Schilder. The author provides an apology for the Pavlovian position, suggesting that Schilder was unfamiliar with early and late writings of Pavlov.     

Reflexology,schizokinesis and autokinesis

A resume of the history and concepts culminating in the work of Pavlov shows that there has been a gradual and slow elaboration toward a science of behavior. The past work has been oriented since the time of Locke increasingly toward the external environment. Pavlov’s theories, however, were directed toward forceswithin the nervous system. Further work from the Pavlovian Laboratories at Johns Hopkins and the V.A. (and elsewhere) indicate that the various physiological systems do not always work harmoniously, but that there is often a split in function (Schizokinesis)—changes occurring over a period of time—which do not seem to be referable to the external environment but to elaborations occurringwithin the organism (Autokinesis). These may tend toward improvement of function or, on the other hand, toward deterioration. The time has come when the progressive changes and the interrelationships of active fociwithin the organism should be considered as well as the reactivity of the individual toward the external environment.     

Pavlovvs. Köhler

During the 1920s, I. P. Pavlov’s scholarly interests broadened to consider problem-solving. Distrusting Wolfgang Köhler’s Gestalt explanation of the problemsolving process and its interspecies aspects, Pavlov performed, from 1933 to 1936, a number of experiments, including a replication of Köhler’s building experiment, using chimpanzees as subjects. Confirming Köhler’s findings, Pavlov explained the problemsolving process in terms of unconditional reflexes and the establishment, by Pavlovian conditioning and the Thorndikian method of trial and error, of temporary neural connections identical, on the psychological level, to associations. In contrast to Köhler’s “structural” explanation, Pavlov emphasized the processes of analysis and synthesis. According to Pavlov insight is achieved progressively—as the result of the organism’s problem-solving behavior—contradicting Köhler’s thesis of a sudden subjective reorganization of the environmental situation. Pavlov explained interspecies differences among higher organisms in terms of the range of a species behavior, with the second signal system as the main distinguishing characteristic between human and nonhuman species.     

On the theoretical foundations of Soviet psychology

Conclusion We are now in a position to examine the claim that Pavlovian physiology and Marxist-Leninist philosophy form two complementary systems.There is certainly a similarity between the Leninist theory of reflection and Pavlov's theory of higher nervous activity. Both present so-called psychic phenomena as a reaction of the organism to the stimuli of the outer world and both insist that this reflection is not a passive reception of impressions but is an active response on the part of the organism.Again both systems are monist; they are united in excluding the possibility of having recourse to a non-material substance as the basis for psychic phenomena. But for Pavlov this exclusion is a scientific axiom while for Marxism-Leninism it is founded on philosophical materialism. However, the most important difference between Pavlov's theories and Marxism-Leninism on this point is that Pavlov's approach to psychic is fundamentally mechanistic and reductionist whereas that of Marxism-Leninism is dialectical and consequently anti-reductionist and anti-mechanist. Soviet psychology is, in consequence, founded partly on a mechanist system which is not materialist in the full sense of the word, and partly on a materialist system which is definitely not mechanist. From this point of view there is a definite discrepancy between the two traditions on which Soviet psychology is founded and which goes a long way towards explaining many of the inconsistencies in Soviet psychological theory.     

Pavlov’s conceptualization of unconditional reflexes,or instincts,within the framework of the theory of higher nervous activity

According to I. P. Pavlov’s theory of higher nervous activity, the establishment and dissolution of conditional reflexes enhances the higher organism’s adaptation to the external environment. Pavlov asserted that, ontogenetically, conditional reflexes are based upon innate, unconditional reflexes (UR) or instincts. Pavlov did not distinguish between URs and instincts, but he preferred the former term. Phylogenetically the URs emerged out of well-established conditional reflexes during the development of higher organisms. An outgrowth of the experimental conditioning procedure, developed during the second decade of this century, was the observation and delineation of new URs. While studying human nervous and psychiatric disorders in the 1930s, Pavlov elucidated other URs. Pavlov identified 13 major URs, but he failed to formulate an exhaustive classification scheme of URs.     

Pavlov’s position toward konorski and miller’s distinction between pavlovian and motor conditioning paradigms

Two Warsaw medical students, Jerzy Konorski and Stefan Miller, having read I. P. Pavlov’s works on conditional reflexes, informed him in a 1928 letter that they had discovered a new type of conditioning. A previously neutral stimulus preceded the passive lifting of a dog’s paw which then was followed by feeding; this stimulus then evoked the spontaneous raising of that paw. Pavlov responded informing them that their conditioning of motor responses expanded his theory of higher nervous activity, but that their conditioning paradigm—that they named CRII—did not differ fundamentally from the Pavlovian conditioning paradigm. The replication of the Warsaw experiment in Pavlov’s laboratory failed to provide unequivocal results. From 1931 to 1933, Konorski, working in Pavlov’s Leningrad laboratory, further explored the parameters of CRII. Pavlov insisted that the conditioning of motor movements differs from the conditioning of other sensory analyzers only in that, on the neural level, the motor analyzer is both afferent, that is, perceptive, and efferent, that is, responsive. Konorski was not convinced, and he subsequently maintained that the two conditioning paradigms were fundamentally different.     

The 1950 Joint Scientific Session: Pavlovians as the accusers and the accused

In 1950, Stalin and the Soviet Government prevailed upon the USSR Academy of Sciences and the USSR Academy of Medical Sciences to organize the 1950 Joint Scientific Session for the purpose of formalizing the teachings of I. P. Pavlov. During the Session, some of Pavlov's erstwhile students—the Pavlovians—split into accusers and accused. The more prominent of the latter were denounced for deviating from the orthodox Pavlovian path, and urged to admit their mistakes, to work within the framework of Pavlov's theory of higher nervous activity, and to avoid Western influence. Within this context, the travail of the prominent Pavlovian physiologist L. A. Orbeli is discussed. Contemporary Russian historians and scientists, evaluating the consequences of the 1950 Joint Scientific Session, point out its negative effects; namely, the general moral decline of Soviet physiologists pressured to accept a dogmatic ideology, the lowering of the quality of research in physiology, and the self-imposed exclusion of Soviet physiology from the worldwide scientific community. © 1997 John Wiley & Sons, Inc.     

Schilder and Pavlov’s theory of higher nervous activity

In the late 1920s, the Viennese psychoanalyst Paul Schilder, after performing a conditioning experiment with human subjects, criticized I. P. Pavlov’s concept of “experimental neurosis.” Schilder maintained that subjective reports by conditioned human subjects were more informative than the objectively observed behavior of conditioned dogs. In 1932, Pavlov published a rejoinder to Schilder’s critique in theJournal of the American Medical Association. Pavlov maintained that Schilder misunderstood the value and implications of the scientific, objective method in the study of experimental neurosis. In 1934, Schilder subjected Pavlov’s theory of higher nervous activity to an incisive critique in a 1935 article inImago. Schilder objected to Pavlov’s narrow, reductionist conceptualization of the conditional reflex. Schilder reiterated his view that the psychological, subjective explanation of the conditional reflex is preferable to the physiological, objective explanation, and that the inference of cortical phenomena from experimental findings might be improper. Neither Pavlov nor any of his disciples replied to Schilder. The author provides an apology for the Pavlovian position, suggesting that Schilder was unfamiliar with early and late writings of Pavlov.     

Pavlov's position on the effects of decortication on conditional reflexes.

This paper examined D. Joravsky's (1989) hypothesis that I.P. Pavlov dogmatically refused to acknowledge that classical conditioning can be mediated by subcortical regions of the large cerebral hemispheres. Decortication literature from 1901 to 1936 was reviewed. The early studies available to Pavlov, who died in 1936, showed that decortication does not allow the establishment of new or retaining of old conditional reflexes (CRs). G.P. Zeleny?'s later experiments(1930) suggested that the establishment of primitive CRs in decorticated dogs was possible. Pavlov never denied this possibility but cautioned that Zeleny?'s experiments could have been methodologically flawed. Although Joravsky's original hypothesis on Pavlov's position on the relation between decortication and the establishment of CRs is by and large accepted, it must be stressed that Pavlov's theory of higher nervous activity was primarily concerned with the function of the brain in the higher organism's struggle for existence. Within this context the cortical, rather than subcortical, processes play the decisive role in the organism's adaptation to the changing external environment.     

A Behaviour Contracting Approach to Weight Control

Anecdotal and research data are accumulating which indicate that stress and lack of reinforcement (depression, loss) are related to the incidence and growth of cancer. Current theories of the etiology of malignant neoplasms involve cellular abnormalities. Pavlovian theorizing concerning the properties of the nervous system is also focused on cellular functioning. Observations from the Pavlovian laboratories indicate that stress (overstrain of the excitatory process and difficulty in mobility of the nervous system) and excessive and/or protracted inhibition (lack of reinforcement) produce both behavioral and organic abnormalities. A current view related to the etiology of cancer that is being seriously considered is the immunocompetence theory. This is consistent with Pavlovian theory. Pavlov himself discussed the likely probability that the immune system can be conditioned. Indeed, there is preliminary research supporting Pavlov's postulation. Treatment of cancer should involve removal of stress and an increase in the level of reinforcement by behavioral means. The general postulation is that stress and/or lack of reinforcement can provide an environment in which abnormal stimulation can increase the susceptibility and growth rate of cancer.     

The politics of physiological psychology Ivan Pavlov’s suppressed defense of scientific freedom and its consequences

This statement, first presented at a plenary session of the Pavlovian Society on 9 October 1992, in Los Angeles, California, attempts to assess the recently released speech delivered by Ivan Pavlov in 1923, but publicly brought to light only in 1991, on the subject of “Communist Dogmatism and the Autonomy of Science.” This speech, noteworthy for the courage of the delivery under adverse circumstances no less than the contents of its remarks, compels a new estimate of the place of science in a totalitarian system boasting an ideology of physiological psychology. It also sheds new light on the Russian Nobel laureate and pioneer in the areas of behavior modification induced by the functions of the higher nervous system. These remarks take an in-depth view of American radical and Marxian appraisals — how they followed the Soviet lead in harnessing Pavlov to the Communist cause, and in attempting to discredit the work of Sigmund Freud. This lethal combination of Communist political needs and ideological proclivities served to rationalize the implementation of slave labor as work therapy during the Stalinist era. The linkage of Pavlov to Makarenko in education and Michurin in biology serves as a case study in the manufacture of tradition. The collapse of the Soviet system permits a recasting of the history of science and Pavlov’s place in Russian life. Such new conditions also provide a lesson in the distortive role of ideology in the evolution of modern science.     

Amygdala and hippocampal activity during acquisition and extinction of human fear conditioning

Previous functional magnetic resonance imaging (fMRI) studies have characterized brain systems involved in conditional response acquisition during Pavlovian fear conditioning. However, the functional neuroanatomy underlying the extinction of human conditional fear remains largely undetermined. The present study used fMRI to examine brain activity during acquisition and extinction of fear conditioning. During the acquisition phase, participants were either exposed to light (CS) presentations that signaled a brief electrical stimulation (paired group) or received light presentations that did not serve as a warning signal (control group). During the extinction phase, half of the paired group subjects continued to receive the same treatment, whereas the remainder received light alone. Control subjects also received light alone during the extinction phase. Changes in metabolic activity within the amygdala and hippocampus support the involvement of these regions in each of the procedural phases of fear conditioning. Hippocampal activity developed during acquisition of the fear response. Amygdala activity increased whenever experimental contingencies were altered, suggesting that this region is involved in processing changes in environmental relationships. The present data show learning-related amygdala and hippocampal activity during human Pavlovian fear conditioning and suggest that the amygdala is particularly important for forming new associations as relationships between stimuli change.     

Roots of the Pavlovian Society''s Missions of the Past and Present: The Pavlov Dimension

This paper offers an interpretation of the relation between Pavlov's life and work and the missions of the Pavlovian Society, both past ("observation and observation") and present ("interdisciplinary research on the integrated organism"). I begin with an account of Pavlov's life and his influence on contemporary thought. I then indicate the relation of some of Pavlov's attitudes (e.g., his motto, his epistemological stance) to the Society's past mission. In the concluding and most controversial section, I argue for six guiding principles derived from Pavlov, to be applied to the Society's mission. These are: (a) a confident methodological behaviorism; (b) a significant role assigned to both physiological and psychological factors in the prediction and control of the integrated organism; (c) approximately equal taxonomic precision of physiological and psychological explanatory concepts; (d) distrust of teleological explanatory concepts; (e) rejection of psychology's instrumentalist "cognitive paradigm shift"; and (f) rejection of the representational theory of knowledge.     

A comparative analysis of the conditional reflex discoveries of pavlov and Twitmyer,and the birth of a paradigm

Research on conditional reflex (CR) in Pavlov’s Physiological Laboratory has preceded Twitmyer’s work on conditioning at the University of Pennsylvania by 3 or 4 years. The events in Pavlov’s laboratory lead toward the postulation of a new paradigm that rejected the Cartesians conceptualization of the reflex as a mechanistic response to stimuli by replacing it with the Darwinian notion of the organism’s adaptation to the environmental conditions. The Pavlovian paradigm rejected the Wundtian method in favor of the objective, conditional reflex method.     

Pavlov and the mind-body problem

I. P. Pavlov claimed that the mind-body problem would ultimately be resolved by empirical methods, rather than by rational arguments. A committed monist, Pavlov was confronted by dualism in the case of an hysterical person. Under normal conditions, her body's left side was insensitive to pain, but when she was hypnotized, there was a reversal of her sensitivity to pain, with the right side becoming insensitive. Pavlov acknowledged that the divergence between stimulation and response suggested dualism, yet condemned his disciple G.P. Zelenyî as well as Charles S. Sherrington, for their dualistic tendencies. Pavlov's continuous adherence to monism is attributed to the influence of popular scientific books that he read during his adolescence. The books maintained that science was based upon monism. Pavlov proposed that by introducing the concept of emotions, an hysterical person's condition could be explained within the framework of his theory of higher nervous activity, thereby obviating the need to change his paradigm.