Pavlov as a psychologist. A reappraisal

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.     

From physiological theory to psychological facts (on the centenary of I. P. Pavlov's speech in Madrid)

Pavlovian theory of conditioned reflexes and Ukhtomsky's theory of dominanta are considered as the most important biological concepts of the XX century. They have laid the foundation of the modern views of the adaptive and active character of the nervous activity underlying the integral behavior in the environment. Approach to a burning problem of neurophysiological mechanisms of goaldirected behavior is impossible without a comprehensive study of works of both these schools. They have formed not only the methodological basis of modern investigations but opened a new avenue of attack.     

I. P. Pavlov and the development of neuroscience

Ivan Petrovitch Pavlov significantly changed and developed our knowledge of the brain functions and of the behaviour by his fundamental experimental and theoretical work on the physiology and pathophysiology of the higher nervous activity. He was one of the scientists who prepared the development of neuroscience in our century. During the Pavlovian Conference, 1950 in Moscow Stalin and the Communist Party tried to dogmatize his and his pupil's fundamental theories. But his pupils continued to develop Pavlovian ideas in open discussions with representatives of other schools in a very creative way, opening the doors for a system approach to understand the integrative functional systems of brain and behavior. Pavlov emphasized the high plasticity of the central nervous system. He investigated the complex functional systems within the brain and between the organism and its environment, and the designed models for pathology of the higher nervous activity. During his last years, Pavlov freed himself from the strong deterministic view and characterized the organism and its environment as a self-organizing system.     

Time Perception and the Feedback Principle

The psychology of time perception, which is increasingly attracting the attention of researchers, finds its explanation in Lenin's theory of reflection and in the Pavlovian concept of higher nervous activity, which is a confirmation in natural science of the Marxist theory of knowledge. Time exists objectively, and is represented to man — by means of time perception — as one of the fundamental forms of being. The essential features and laws of such perception are determined by the interaction of excitatory and inhibitory cortical processes. However, a number of mechanisms involved in carrying out this process of representation have, as yet, been little investigated. The feedback principle would appear to offer a fruitful approach in this regard. This principle, along with comparison theory, makes possible a new interpretation and generalization of the large amount of experimental data that has already been accumulated on the psychology of temporal perceptions.     

Neural and Pavlovian influences on immunity

The traditional view that the nervous and immune systems are functionally independent (aside from general stress effects and autoimmune disorders of the nervous system) is being challenged by a new view that the nervous system regulates the activity of the immune system. If this is true, it should be possible to change the activity of the immune system by means of Pavlovian conditioning, just as it is possible to condition other physiological events influenced by the autonomic nervous system or neuroendocrine substances. Evidence for autonomic and neuroendocrine modulation of immune activity is briefly reviewed; and, the various studies reporting conditioned immune effects, the physiological mechanisms most likely involved, and their possible significance are discussed.     

The contribution of Academician L. A. Orbeli to the theory of higher nervous activity]

In the paper are discussed the main directions of the investigation of the higher nervous activity, fruitfully developed by academician L. A. Orbeli and his school. These directions are the following: the evolutionary approach, the study of the influence of the sympathetic nervous and endocrine systems, of the role of the extracortical brain structures, especially the hypothalamus and the cerebellum, and the significance of pain and efferent systems for the higher nervous activity.     

History of the mainstream scientific research at the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences

The classical reflex theory of the higher nervous activity has been developed in the works of E.A. Asratyan, the first director of the Institute, and his scientific school. The novel aspects of the theory have been developed: the principle of system organization; the concept of the nervous center as a set of structures located in different areas of the central nervous system; conditioned switchover, the mechanism of conditioned connection closure; the origin and localization of conditioned inhibition; the two-way, forward and backward conditioned connections. The elaboration of physiological mechanisms of the active goal-directed motivated behavior was begun. V.S. Rusinov and his collaborates have developed the concept of the dominanta and role of the stationary excitation foci in the integrative brain activity. M.N. Livanov has created the concept of the spatio-temporal organization of bioelectric potential and systemic organization of brain activity. P.V. Simonov, beginning from 1964, has developed the need-informational theory of the human and animal higher nervous activity (behavior). As distinct from the theories that originate from a single viewpoint and reject all the others, Simonov's theory is integrative and follows the logic of development of brain science.     

Evolutionary learning circuits

This paper presents a theory of the central nervous system based on information processing concepts suitable for describing molecular biological systems. The main features of the theory are (1) the CNS consists of various types of unit regions of which there are many interchangeable replicas; (2) each region contains neurons whose firing is determined by excitase enzymes which recognize specific patterns of inputs and which may be coded by genes which are either heritable or culturable; (3) the CNS has selection circuits which test and evaluate individual regions and which control the production of culturable excitase genes on the basis of this evaluation. The genes whose production is stimulated diffuse out of the regions in which they are produced to transform other, competent regions of the same type. The function of the excitase molecules is the same in these new regions because the tissue structure and cellular properties are the same. This makes it possible for trial and error learning to be mediated by the same mechanisms as natural evolution, except that it is more efficient due to the selection circuits. Systems operating on the above basis are capable of performing any operation performable by a conventional computer, but with certain important restrictions on programmability. Such systems are also (structurally) simpler than conventional information processing devices and more amenable to learning and evolution. The theory makes a number of definite predictions about the CNS, some of which correspond to known facts and others of which are testable.     

Comparative Study of Neurochemical Compensation of Disturbed Brain Functions in Mammals

In a comparative row of mammals (hedgehogs, rabbits, monkeys), the role of the opioid neuropeptide Met-encephalin (ME) and the hypothalamic neurohormone vasopressin (VP) was studied in possibility of compensation of disturbed higher nervous functions in organic and functional pathologies of the higher nervous activity. Administration of ME and VP under conditions of destruction of neocortex in hedgehogs was found to restore predominantly congenital forms of the nervous activity. In rabbits, on administration of VP, a tendency is revealed for restoration of acquired forms of the nervous activity; however, it is of a limited character. On administration of ME and VP under conditions of functional pathology a similar regularity in restoration of disturbed higher nervous functions is observed. Injection of ME and VP to hedgehogs produced a more pronounced and longer effect on unconditioned reflexes. The effect of low doses of VP on HNA is of short-term, generally facilitating character. In rabbits, on the background of VP, the memory processes (trace conditioned responses) are briefly restored and are enhanced. In monkeys, the effect of ME and VP on acquired forms of the nervous activity and on various functional systems is of differential character. The VP compensatory effects are more pronounced after administration of low VP doses. The effects of ME and VP on congenital forms of the nervous activity are negligible. The established regularities are discussed and interpreted from the viewpoint of the concepts postulated by A.I. Karamyan about evolution of the compensatory brain activity, evolution of neocortex, and an increase of its neuroplasticity.     

Feedback and the typological characteristics of higher nervous activity]

Apparatus of the theory of automatic regulation and control systems is applied for explanation of typological characteristics of the higher nervous activity. On the basis of the analysis of activity of four types of automatic control systems a hypothesis is suggested that these characteristics are connected with organization of the feedback in the functional system, and analogies drawn between the types of the higher nervous activity and types of automatic systems.     

On the nature and origin of cellular complexity: The combinatorial–eukaryogenetic scenario

The ideas on the nature and origin of the cell nucleus published by K.S. Merezhkowsky in his book The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study on the Origins of Organisms (1909) are still relevant. In this book, Merezhkowsky (1909, p. 86) wrote, “Part of my theory related to the nucleus, its nature and origin will be the subject of a separate paper, which will present facts serving as the basis for the ideas, which are here only touched upon briefly.” For various reasons, he was not able to publish the paper intended. Therefore, I here attempt to interpret Merezhkowsky’s original concepts on the nature and origin of the cell nucleus in a modern context.     

The effect of vasopressin on memory processes in Macaca fascicularis]

The role of vasopressin (arginin-vasopressin) in the regulation of conditioned instrumental food-procuring reactions and different kinds of memory such as delayed reflexes, image, short-, and long-time memory was studied in monkeys. Motor and autonomic effects of vasopressin were assessed. It was found that in monkeys, vasopressin administration differently affected the simple conditioned food-procuring reactions and memory. During functional disorders of the higher nervous activity, vasopressin was more efficient in its action on memory and its restoration. Formation of two types of vasopressin effects on the higher nervous activity in evolution of mammals is discussed.     

Marvelling at the Marvel: The Supposed Conversion of A.D. Darbishire to Mendelism

The so-called “biometric-Mendelian controversy” has received much attention from science studies scholars. This paper focuses on one scientist involved in this debate, Arthur Dukinfield Darbishire, who performed a series of hybridization experiments with mice beginning in 1901. Previous historical work on Darbishire’s experiments and his later attempt to reconcile Mendelian and biometric views describe Darbishire as eventually being “converted”' to Mendelism. I provide a new analysis of this episode in the context of Darbishire’s experimental results, his underlying epistemology, and his influence on the broader debate surrounding the rediscovery and acceptance of Mendelism. Iinvestigate various historiographical issues raised by this episode in order to reflect on the idea of “conversion” to a scientific theory. Darbishire was an influential figure who resisted strong forces compelling him to convert prematurely due to his requirements that the new theory account for particularly important anomalous facts and answer the most pressing questions in the field. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nerve endings of the walls of the descendent colon and rectum

Summary Two types of nerve endings in the muscular wall of the descendent colon and rectum are shown in this paper. The first one, is constituted by thick extrinsic fibers ending by neurofibrillar sharpened points which are subdivided in two groups; unlimited endings having its branches placed among the muscular fascicles is one of them (interfascicular nerve endings). The other one belongs to limited endings sited in connective spaces sourrounded by the muscular bundles. The second type of neuromuscular relation is integrated by long and slender fibers. In some cases its origine of a local neuron was prooved by us.Endings in the mucous layer were also found. The Lieberkühn glands have nervous fibers distributing only at its bottom; nervous fibers supply only the upper part of the glands and also the epithelial surface, and an intermediary type of them distributing its branches to the whole width of the mucosae.     

The role of macrophage subpopulations in autoimmune disease of the central nervous system

Summary In this review the role of various subpopulations of macrophages in the pathogenesis of experimental autoimmune encephalomyetitis is discussed. Immunohistochemistry with macrophage markers shows that in this disease different populations of macrophages (i.e. perivascular cells, microglia and infiltrating blood-borne macrophages) are present in the central nervous system. These subpopulations partially overlap in some functional activity while other activities seem to be restricted to a distinct subpopulation, indicating that these subpopulations have different roles in the pathogenesis of encephalomyelitis. The studies discussed in this review reveal that immunocytochemical and morphological studies, combined with new techniques such asin situ nick translation and experimental approaches like the use of bone marrow chimeras and macrophage depletion techniques, give valuable information about the types and functions of cells involved in central nervous system inflammation. The review is divided in three parts. In the first part the experimental autoimmune encephalomyelitis model is introduced. The second part gives an overview of the origin, morphology and functions of the various subpopulations. In the third part the role of these subpopulations is discussed in relation to the various stages (i.e. preclinical, clinical and recovery) of the experimental disease.     

Neuronal spike trains and stochastic point processes. I. The single spike train

In a growing class of neurophysiological experiments, the train of impulses (“spikes”) produced by a nerve cell is subjected to statistical treatment involving the time intervals between spikes. The statistical techniques available for the analysis of single spike trains are described and related to the underlying mathematical theory, that of stochastic point processes, i.e., of stochastic processes whose realizations may be described as series of point events occurring in time, separated by random intervals. For single stationary spike trains, several orders of complexity of statistical treatment are described; the major distinction is that between statistical measures that depend in an essential way on the serial order of interspike intervals and those that are order-independent. The interrelations among the several types of calculations are shown, and an attempt is made to ameliorate the current nomenclatural confusion in this field. Applications, interpretations, and potential difficulties of the statistical techniques are discussed, with special reference to types of spike trains encountered experimentally. Next, the related types of analysis are described for experiments which involve repeated presentations of a brief, isolated stimulus. Finally, the effects of nonstationarity, e.g. long-term changes in firing rate, on the various statistical measures are discussed. Several commonly observed patterns of spike activity are shown to be differentially sensitive to such changes. A companion paper covers the analysis of simultaneously observed spike trains.