Prospects for Solving the Psychophysiological Problem: Brain Activity, the Mind, and Consciousness Phenomena

27.11.1928–12.03. 2026

On March 12, 2026, Natalia Ivanovna Chuprikova, Doctor of Psychology and Professor Emerita of the Psychological Institute of the Russian Academy of Education, passed away. She was a patriarch of Russian psychology, a preeminent scholar in the fields of psychophysiology, the theory of higher nervous activity, and developmental psychology. Her scientific legacy spanned an entire epoch in the development of Russian psychological thought. Chuprikova served as a crystallizing center of genuinely free scientific inquiry, distinguished by her independent scientific stance and her uncompromising commitment to the criteria of scientific rigor. Under her mentorship, a cohort of scientists emerged who, in their groundbreaking research grounded in the differentiation–integration principle of development, break down interdisciplinary barriers and, within a unified terminological framework, lay the foundation for a psychology of the new millennium.

The key milestones of N.I. Chuprikova’s scientific legacy are presented in the second issue of the journal Natural Systems of Mind (2024, Volume 4, Issue 2) in the section “Learning from the past”.  In this regard, the editorial board of the journal decided to publish in this issue excerpts from a letter from N.I. Chuprikova to K.V. Anokhin, which should be considered as a testament to scientists in the field of neuroscience – an uncompromising call for methodological rigor and a warning against replacing objective analysis with mythologized constructs of consciousness and free will.

Brief Considerations on Some Theoretical Aspects of Neuroscience

1. On the translation of the term mind. The English term mind is more adequately translated into Russian not as “reason” (razum) but as “psyche” (psikhika). In the English-language tradition, the concept of mind encompasses sensations, feelings, memory, thinking, intentions, desires, needs, as well as the conscious and the unconscious. In the Russian philosophical and psychological tradition, all these phenomena are denoted by the term “psyche.” The Russian word razum (“reason”) refers only to a subset of mental phenomena. Thus, in terms of content and scope, the English mind is equivalent to the Russian “psyche.” Accordingly, the mind-body problem and the mind-brain problem correspond in the Russian tradition to the psychophysical and psychophysiological problems, respectively.
2. The hypernetwork and the representational-verbal system. The characteristics attributed to the hypernetwork pertain to the extensive representational-verbal system of humans. The presentation of the word “house” activates an infinite number of associations (my house, the neighbor’s house, the street, furniture, residents, parts of the house, etc.). This does not occur when simply viewing a picture of a house (unless the picture activates the verbal network). Animals either lack such an extensive representational-verbal system or possess only its rudimentary form.
3. The qualitative difference of the human brain. According to I.P. Pavlov, the functioning of the human brain and its higher nervous activity qualitatively differ from those of animals due to the “grand signalization of speech” (Pavlov’s expression). Unfortunately, contemporary science does not always appreciate this difference. As the author has repeatedly noted (particularly in her latest book), the significance of Pavlov’s idea was understood only by L.S. Vygotsky.
4. K.V. Anokhin’s “wormholes” metaphor and E.I. Boyko’s theory of dynamic temporary neural connections. With regard to the “wormholes” metaphor proposed by K.V. Anokhin, it is relevant to recall E.I. Boyko’s theory (1950s–1960s). Boyko postulated three types of excitation propagation via neural connections:

• unconditional, innate, permanent, genetically specified connections;
• temporary connections (Pavlovian), formed on the basis of the coincidence of excitation foci and underlying individually acquired behavior and learning;
• dynamic connections, which arise emergently without prior formation, as a result of the interaction of generalized “closure” connections (extraction of common elements, specialization of excitation).
• Boyko’s theory drew on I.M. Sechenov’s conception of thinking as mental comparison, J.S. Mill’s theory of inductive reasoning, and experimental data from Boyko’s own laboratory. Key works include Borderline Problems of Psychology and Psychophysiology (Boyko, 1961), Human Reaction Time (Boyko, 1964), and Mechanisms of Mental Activity (Boyko, 1976). This theory may serve as an important prerequisite for a general theory of brain function, and the “wormholes” metaphor may illustrate the spontaneous emergence of new pathways of excitation.

5. Vygotsky’s assessment of Pavlov’s methodology and the current state of neuroscience. L.S. Vygotsky held Pavlov’s methodology for studying brain activity in high regard. Vygotsky considered the fine imposed by Pavlov in his laboratory for the use of psychological concepts to be a fact of no lesser significance than the dispute over the creed in the history of religion, because the fine targeted causeless, spaceless, indefinite, mythological thinking. Unfortunately, contemporary neuroscience exhibits an excess of such thinking. An example is B. Libet’s experiments: the subject receives a verbal instruction to voluntarily raise either the right or left hand. The task of science is to establish the physiological mechanisms by which this instruction is implemented, whereas theorists attempt to explain the nature of a complex objective brain process through even more vague concepts such as “consciousness” and “free will.” This exemplifies the substitution of objective analysis with subjective constructs.

These considerations are offered to colleagues in the hope that they may prove useful for theoretical developments in neuroscience.

N.I. Chuprikova

Prospects for Solving the Psychophysiological Problem: Brain Activity, the Mind, and Consciousness Phenomena

N. I. Chuprikova

Psychological Institute of the Russian Academy of Education, Moscow, Russia

The manuscript was first published in 2018 in Psychological Journal [Psikhologicheskii Zhurnal]: Chuprikova, N. I. (2018). Prospects for solving the psychophysiological problem: Brain activity, the mind, and consciousness phenomena. Psikhologicheskii Zhurnal, 39(2), 120–133.

Abstract. The current state of the psychophysiological problem is analyzed. It is concluded that the opinion of Crick (1982) and Nagel (2001) is correct: the inability to clearly reveal the connection between the mind and brain activity indicates the inadequacy of our concepts of the mind, consciousness, and brain activity, and therefore requires a radical revision of their content. An attempt is made to show how such new concepts can be developed. The proposed basis for their development is the understanding, established in Russian psychology, of the mind as a reflection of reality necessary for the regulation of behavior and activity, and of the brain as the bodily organ that, in evolution, has taken on this function. The idea of the cerebral “embodiment” of reality in acts of sensory-perceptual cognition and of the physiological mechanisms of consciousness, owing to which their content is disclosed to the human being as a subject of cognition and activity, is developed. Sechenov’s (1947, 1952) non‑Cartesian theory of reflex brain activity, Spinoza’s monistic theory of the relationship between mind and body, Brentano’s theory of intentional acts of consciousness (see Yaroshevsky, 1976), and the conception of Edelman (1981, 2012) and Ivanitsky (1999, 2004) on the recurrent return of excitations to sensory‑perceptual areas of the brain as a mechanism of consciousness are drawn into the discussion. The general propositions developed are concretized by examining the neurophysiological mechanisms of the reflection of space and its phenomenal representation in human consciousness.

Перспективы решения психофизиологической проблемы:

деятельность мозга, психика и явления сознания

Н.И. Чуприкова

Психологический институт Российской академии образования, Москва, Россия

Резюме. Анализируется современное состояние психофизиологической проблемы. Делается вывод о справедливости мнения Ф. Крика и Т. Нагеля, что неспособность ясно раскрыть связь между психикой и деятельностью мозга свидетельствует о неадекватности наших понятий о психике, сознании и деятельности мозга и поэтому требует кардинального пересмотра их содержания. Делается попытка показать, как могут быть выработаны такие новые понятия. В основу их выработки предлагается положить сложившееся в отечественной психологии понимание психики как отражения действительности, необходимого для регуляции поведения и деятельности, а мозга – как телесного органа, взявшего на себя в эволюции осуществление этой функции. Развивается представление о мозговом “воплощении” действительности в актах ее сенсорно-перцептивного познания и о физиологических механизмах сознания, благодаря которым их содержание открывается человеку как субъекту познания и деятельности. К обсуждению привлекаются некартезианская теория рефлекторной деятельности мозга И.М. Сеченова, монистическая теория соотношения души и тела Спинозы, теория интенциональных актов сознания Ф. Брентано, концепция Дж. Эдельмана и А.М. Иваницкого о повторном приходе возбуждений к сенсорно-перцептивным областям мозга как механизме сознания. Развиваемые общие положения конкретизируются на примере рассмотрения нейрофизиологических механизмов отражения пространства и его феноменальной представленности в сознании человека.

Ключевые слова: психика, сознание, деятельность мозга, психофизиологическая проблема, теория отражения, интенциональные акты сознания

Introduction

1. The Theory of Reflection as a Basis for Solving the Psychophysiological Problem

At the present time, hardly anyone seriously doubts that our mind and our consciousness are generated by our brain and are its function. According to Nagel (1998), an active participant in contemporary discussions of the psychophysical problem, there is no doubt today that the mental is always accompanied by the physical, that there can be no mental differences without corresponding physical differences. However, Nagel’s (1998) profound thought is that such accompaniment (the correspondence of one to the other) remains a purely empirical fact, the nature and necessity of which are unclear. We cannot propose, he says, a clear theoretical conception that would allow us to understand in what necessary way subjective and physical properties can be simultaneously essential aspects of a single essence or process.

The essence of the theoretical failure to understand the relationship between the psyche and brain activity usually takes the form of the assertion that we do not understand how and why mental phenomena arise in brain structures. Some authors claim that the absence of a logical bridge between psychology and brain physiology indicates a fundamental ontological gap between the mental and the physical, from which they conclude that materialism is false and that some form of dualism may be true. Others believe that the issue is not an ontological gap (which does not actually exist) but our inability to cope with the hard problem.

Nagel (1998) holds the second view, seeing the main cause of difficulties in solving the psychophysiological problem in the inadequacy of the concepts we use. He writes that if, when considering the relationship between consciousness and physical processes in the brain, our concepts are unable to reveal the necessary connection between them that science has established and that actually exists, then most likely we should recognize our concepts as radically inadequate. A revision is required of how we conceive either consciousness or matter, or both. Crick (1979) wrote that if we are unable to resolve the question of the relationship between consciousness and brain activity in a consistent scientific manner, this suggests that our whole way of thinking about such problems may be mistaken. The history of physics vividly demonstrates how firmly established facts that did not fit into the Procrustean bed of existing concepts led to a revision and change in the content of the cardinal physical concepts of matter, motion, space, and time. It seems that in psychology today, particularly in connection with the need for a scientific solution to the psychophysical problem, there is an urgent need for a critical analysis and revision of the content of many of its basic concepts.

Many years of analysis of the logical dead ends on the path to a monistic materialistic solution to the psychophysiological (mind‑body) problem have led me to conclude that they are rooted not in any fundamental essential differences between the nature of the psyche and brain activity (which we either do not know or cannot understand), but exclusively in the inadequacy of the concepts used in discussing the problem, both about the psyche and about brain activity (Chuprikova, 1985, 2010, 2015, 2016).

In the briefest form, the traditional concepts of psyche and brain activity come down to the following.

1. When discussing the psychophysiological problem, mental phenomena are treated essentially exclusively in the spirit of classical introspectionist psychology. They are understood as phenomena devoid of any materiality, lacking objective existence, as purely subjective phenomena accessible only to the self‑observation of the subject to whom they belong. With such a treatment, the concepts of the mind and consciousness become identical, and the representation of the mind in consciousness in the form of subjective experiences appears as its immanent, integral property.
2. Brain activity is treated in the Cartesian spirit, exclusively as purely material, physical, or physicochemical, by definition proceeding without any participation of the mind and consciousness, i.e., without the participation of what in English is denoted by the term mind. In contemporary treatments, this is the activity of neurons and their connections; it is some “computations” that the brain performs in solving various behavioral and cognitive tasks.

It is clear that from such initial positions, the mind and matter (brain activity) from the very beginning appear as absolutely different worlds. These positions already initially contain an absolute ontological dualism of spirit and matter, the mind and brain activity. Therefore, any rational understanding of their actually revealed connection is fundamentally impossible. Let us cite the expressive words of Galperin (1992): “The true source of the ‘open crisis of psychology’ was and remains ontological dualism – the recognition of matter and the mind as two worlds absolutely different from each other. It is characteristic that none of the militant directions of the crisis period questioned this dualism. … If we think of them as absolutely opposite kinds of being, then this transition really cannot be understood” (Galperin, 1992, p. 3).

The only way out is to radically revise and change the traditionally established concepts of the mind, consciousness, and brain activity, as Nagel (1998) and Crick (1979) argued.

Even at the turn of the 19th–20th centuries, views were expressed that if the mind arose in evolution and exists for some reason, it must necessarily play some unique, indispensable adaptive role in the life and survival of organisms. Lange (1914) wrote that the mind is a special real-life process inherent in all living organisms and developing in their series along with the general evolution from lower to higher forms. The mind is a special way of adapting the organism to the environment, helping it in the struggle for existence. However, the question of what this special real-life process is, how it differs from all other life processes, what its nature is, and how exactly it ensures the adaptation of organisms to the environment remained open.

A general answer to this question can be given within the framework of the understanding adopted in Russian psychology of the mind as a reflection of reality necessary for the regulation of behavior and activity. Within this approach, the behavior of living beings can only be successful and ensure their survival and development because it is consistent with the conditions of their external and internal environment. And this requires the organism to reflect these conditions. Since mental activity is carried out by the brain of living beings, reliance on the theory of reflection makes it possible to overcome the Cartesian physicalist‑mechanistic understanding of brain activity. The theory of reflection dictates an understanding of this activity as reflective in its nature and function, i.e., as immanently mental activity, rather than non-mental, as traditionally assumed by the overwhelming majority of authors discussing the psychophysiological problem.

From the standpoint of the theory of reflection, the mental is qualitatively specific bodily‑brain processes in which reality existing outside them is reflected (represented, reproduced, recreated, embodied). Due to the representation of reality in brain activity, and only thanks to such representation, these unique brain processes, ensembles of excitations from which arrive at the executive organs, act as regulators of behavior and activity, coordinating the parameters of their work with the requirements of the external and internal conditions of life of animals and humans.

This outlined conception was first developed in clear form by Sechenov (1947, 1952). In his works Reflexes of the Brain, Who and How to Develop Psychology, Elements of Thought (Sechenov, 1947), and Physiology of Nerve Centers (Sechenov, 1952), the mind in the form of sensation was initially introduced into the composition of reflexes as a function of their central brain link. The central brain link of the reflex in Sechenov’s interpretation is not just a device for purely mechanical transmission of nerve impulses from receptors to effectors. This device is an organ of sensation and a director of actions adequate to the external and internal conditions of the organism’s life. Sensation, according to Sechenov, does not at all presuppose its necessary conscious form. Wherever the nature of the response acts indicates the ability of an animal or human to distinguish the conditions of stimulation that cause movement, we should speak of sensation. Therefore, Sechenov’s well‑known thesis about the coordination of movements with sensation reveals the substantive causal link between the flexible coordination of movements and the infinitely varying characteristics of the stimuli that cause them. The strictly lawful nature of response acts in Sechenov’s (1947) reflex theory fully retains its force, but the determination of behavior includes the reflection and discrimination by the nervous system of the quantitative and qualitative characteristics of stimulation, i.e., what is usually called the mind. The function of sensation postulated by Sechenov, revealed in the simplest elementary reflex acts, fully retains, from his point of view, its force with respect to manifestations of instinct and reason, when sensation becomes highly developed, highly differentiated, and coordinated (Sechenov, 1947, p. 416). According to the fair assessment of Yaroshevsky (1976), Sechenov radically (one might even say revolutionarily) transformed the concept of the reflex as a concept characterizing the deterministic principle of brain activity, and at the same time presented the mental itself in a fundamentally new way (Yaroshevsky, 1976, pp. 235, 237). Unfortunately, Sechenov’s position regarding the non‑Cartesian understanding of the nature of reflex brain activity remains completely unclaimed in psychology, philosophy, and neuroscience.

In his polemic with Kavelin, Sechenov (1947) sharply rejected the latter’s assertion that he allegedly tried to derive the essence of the mental, its content, from the “structure of the nerve centers”. There is no question of any such derivation in Sechenov. His position is completely different. It consists in the fact that there is a triune nervous reflex act (the simplest or the most complex), beginning with an external influence, ending with movement, and containing a middle central element located between them. In this triune system, the external impulse becomes the productive cause of adequate movement only because it turns into a sensation that “serves as an instrument for distinguishing the conditions of action”. Sensation in Sechenov (1947) is a content‑functional characteristic of the work of nerve centers[1].

In its general meaning, Sechenov’s theory fully corresponds to Spinoza’s philosophical monistic theory, according to which body and soul are one and the same “thing,” one and the same substance, presented in one case under the attribute of extension and in the other under the attribute of thinking. In modern language, there are special psychophysiological processes in the working brain that, taken under the attribute of extension, appear as the most complex activity of its nerve cells and their ensembles, and under the attribute of thinking, as their content reflecting (embodying in themselves) the content of the external world and the internal states of the organism itself (Chuprikova, 2010, 2015).

Within the frameworks of Sechenov’s (1947, 1952) and Spinoza’s theories, there are no separate independent mental processes on the one hand, and brain activity processes on the other. There are unified psychophysiological processes that have a dual material‑ideal nature. They are material because they are from beginning to end extended and material. They are ideal in their content because they embody (recreate, reproduce) and carry within themselves reality existing outside them.

This understanding of things makes it possible to transfer the psychophysical (psychophysiological) problem from the realm of philosophical speculation to the realm of concrete scientific research. It will be necessary to answer concretely how exactly the reality lying outside the nervous system and the brain (the external world and the internal states of the living being itself) is embodied in the activity of its nervous system and brain, what these “neural embodiments” are, and how exactly they, arriving at the executive organs, provide behavior adequate to the external environment and the coordinated work of all other organs and systems of the organism.

“Neural embodiments” of the contents of the external world and internal states of the organism do not presuppose an immanent subjective representation inherently belonging to them, i.e., an immanent givenness of the object to the subject. Today it is well known that a person (not to mention animals) “is capable of carrying out complex adaptive processes controlled by environmental objects without being at all aware of the presence of their image; he avoids obstacles and manipulates things as if without seeing them” (Leontiev, 1975, p. 125). Subjective introspective givenness of objects to the subject is not always a necessarily and immediately arising concomitant of the images of these objects represented in their “brain embodiments”. It is a consequence of special additional physiological mechanisms that are mechanisms of consciousness and verbalization of external and internal impressions. These are mechanisms of the recurrent return of excitations from higher brain centers associated with memory, language, and the self‑image to the primary brain projections of the “neural embodiments” of external world objects and internal states of the organism that arise upon their direct action on the sense organs (Chuprikova, 1985, 2015; Edelman, 1982, 2001; Ivanitskii, 1999, 2004;). When such a recurrent return of excitations occurs, the content of the “neural embodiments” of particular external or internal stimuli becomes conscious and can be verbalized.

Today, an attempt can be made to demonstrate the possibility of a concrete scientific implementation of the idea of “neural embodiments” of reality as unified psychophysiological processes having a dual material‑ideal nature, and then on this basis to show how their subjective representation in consciousness can arise. Below, such an attempt will be implemented using the example of the mechanisms of reflection of space in animals and humans and its subjective representation in human consciousness.

[1]A prominent representative of neobehaviorism, E. Tolman (1932), arrived at a similar scheme for the organization of behavioral acts. Although his statements are less definite and less “materialistic” than Sechenov’s, in essence, Tolman said the same thing as Sechenov. Tolman argued that immanent in any behavior there are certain immediate “inherent” goals and cognitive processes. He maintained that these functionally defined variables are the final link in the causal control of the determinants of behavior, and that they must be discovered and defined by appropriate experimental procedures. Tolman emphasized that these variables are objective, and that it is we, the external observers, who, having discovered them, infer or even invent them as immanent determinants of behavior. According to Tolman, they are the most immediate and ultimate causes of behavior, which he called “immanent determinants.” However, he added that immanent determinants themselves are caused by environmental stimuli and initial physiological states. Such environmental stimuli and physiological states, Tolman noted, are designated as the ultimate or “initial causes” of behavior. Thus, immanent determinants are included in the causal chain between the initial causes and behavior as the final outcome.

Discussion

2. Mechanisms of Reflection of Space and Its Subjective Representation in Human Consciousness

The problem of space perception is one of the classic fundamental problems of psychology. The fundamental question of this problem with respect to vision is how one can see distances to objects and between them, their relief and depth, i.e., see the world as voluminous and three‑dimensional, when all its projections on the retina are two‑dimensional. As written in the book on experimental psychology by Woodworth, we would like to find those cues, those sensory data, that we use in the visual perception of space, and to decipher as far as possible the very process of their use.

As a result of many experimental studies, it has been possible to find and describe those specific cues of vision and proprioception that provide visual perception of depth and distance and that are still reported in all textbooks and manuals on the psychology of perception. For example, Schiffman (2003) and Chuprikova (2009, 2015) discuss them. To denote the sensory cues necessary for three‑dimensional spatial perception, the concept of a cue (or “sign”) was introduced. By cues are meant the two‑dimensional characteristics of retinal images and proprioceptive sensations during accommodation of the lens and convergence of the eyes, the presence of which regularly entails a volumetric three‑dimensional perception of reality. However, the mechanisms of using the found cues of three‑dimensional space remain largely undeciphered. At the same time, the regular objective relationship between the non‑spatial cues of space and their objective spatial source in the real world, the relationship that allows humans and animals to very accurately and reliably reflect the distances between their body and surrounding objects, which finds expression in the striking accuracy of aiming and grasping movements, also remains unclear.

This article attempts to shed some light on these questions and thereby show how, with respect to the perception of three‑dimensional space, the gap between the description of its physiological mechanisms and its representation in human consciousness can be overcome.

To approach the solution of the efficacy of non‑spatial cues of space, it makes sense to begin not with the complex set of cues of human spatial vision, but with a simpler and more demonstrative example of the spatial behavior of one of the highly organized arthropods – the scorpion, which lives on southern sandy soils.

The literature describes the results of a cycle of behavioral, psychophysical, and neurophysiological studies that shed light on how the scorpion, living on sandy soils, catches its prey by an accurate targeted jump when the prey lands at various distances from itself (Frolov, 2002).

From physics it is known that the fall of an object onto sandy soil causes two types of propagating wave vibrations – Rayleigh surface waves and deep compression waves. Surface waves propagate at a lower speed (40–50 m/s) than compression waves (120–200 m/s). It turned out that the scorpion’s vibration sensitivity organs detect these different types of waves caused by the prey landing on the sand. The so‑called slit sensilla respond to Rayleigh waves, and sensory hairs respond to compression waves. The distance to the target is determined by the magnitude of the delay between these two responses. Since the difference in the arrival time of the two waves at the scorpion’s sense organs regularly depends on the distance they have traveled from their source, it serves as a reliable determinant of the distance to that source, i.e., to the prey. But in order to use this temporal difference between the occurrence of two excitations in behavior, the scorpion’s nervous system must have neurons that are tuned to this difference, superposed on the first layer of vibration receptors. The necessity of their existence follows from the general physiological theory of detector neurons. The astonishing accuracy of the neuronal system is striking: based on the difference in arrival time of two successive waves at the vibration receptors, it precisely “computes” the distance to their source, and then sends precisely dosed commands to the motor organs, causing muscle contractions of the animal’s limbs of different strengths. And different strengths of muscle contractions lead to the actual recovery of the distance to the prey in the particular length of the scorpion’s jump (Frolov, 2002).

From the above, we can conclude that the difference in the arrival time of the two waves, surface and deep, at the scorpion’s vibration receptors is undoubtedly a reliable cue of the distance to the prey that has landed on the sand. At the same time, a more important and fundamental conclusion may be that this difference is a function of the distance that two waves having different propagation speeds travel from their point of origin to the moment they meet the insect’s receptors, T₂ – T₁ = F(distance), and that this function is precisely reflected in the receptors and nervous system of the scorpion.

The distance function is reflected by the scorpion’s nervous system in two successive stages. First, on the surface of the vibration receptors, two separate foci of excitation arise sequentially with a certain delay. Then a new layer of detector neurons, selectively tuned to detect a particular specific magnitude of the temporal delay of these two excitations, must determine which particular magnitude occurred in each specific case. Finally, based on this magnitude, the real distance to the prey is again recovered in the length of the animal’s jump. This is possible because the difference T₂ – T₁, detected by the detectors in the scorpion’s central neurons, must be translated into a strictly distance‑proportional strength of muscle contractions of the animal’s limbs. The specific mechanism of such translation is unknown today. Its study will have to reveal how, specifically with respect to spatial perception and spatial behavior, that coordination of movements with sensation, which according to Sechenov (1947) is the essential function of the psyche, is carried out.

In the relatively simple nervous system of the scorpion, an ensemble of excitation of detector neurons specific to each distance can be assigned to the function of each particular distance to the prey. And the totality of all distance detector neurons present in the nervous system can be regarded as a “neural embodiment” of all practically used distances to the prey, i.e., as a “neural embodiment” of the objective three‑dimensional space accessible to the scorpion.

Let us now turn to visual space perception in humans.

Currently, the cues of space perception are divided into visual (features of retinal images) and non‑visual (features of proprioceptive sensations during accommodation of the lens and convergence of the eyes).

Visual cues are divided, on one basis, into monocular and binocular, and on another basis, into static and dynamic. Static cues occur when the eyes are stationary, while dynamic cues arise during movements of the observer’s eyes and head.

Let us briefly list the main firmly established cues that provide visual perception of space (depth, remoteness, distances).

Monocular visual static cues:

• Linear perspective
• Aerial perspective
• Partial occlusion of a more distant object by a nearer one
• Brightness and shading
• Surface texture gradient

Binocular visual static cue:

• Binocular parallax, or binocular disparity

Monocular visual dynamic cue:

• Motion parallax

Monocular and binocular non‑visual dynamic cues:

• Degree of accommodation of the lens
• Degree of convergence of the eyes

If we look at the visual cues of space, it is not difficult to see that they are based on the registration by the visual system of certain functions of distance that arise on the retina due to differences in the projections of objects at different distances.

Linear perspective is a function of distance as a system of progressively and proportionally decreasing size of retinal images of objects as they recede from the observer’s eyes.

Binocular parallax is a function of distance expressed through the magnitude of differences in the images of objects on the retinas of the right and left eyes, which is proportional to the distance of objects from the observer. At the level of the eye’s receptors, this function appears as binocular disparity, and at higher levels of the visual system it is represented in the excitation of disparity detectors described in the literature, selectively tuned to its various values (Schiffman, 2001; Sokolov, 2003). The neurophysiological mechanism of binocular spatial vision is quite complex in all its details, but the most general principle of binocular perception of depth and distance is simple and consists in the fact that one quite definite function of distance is used here.

Other visual distance cues are based on the visual system’s use of other distance functions formed on the retina by differences in the projections of objects at different distances. Some of these functions are relatively simple, others are more complex.

Aerial perspective, occlusion of a more distant object by a nearer one, surface texture gradient, brightness and shading – these are relatively not very complex functions of distance and depth, reflected by retinal receptors and higher levels of the visual system. Apparently, the most complex function is motion parallax. It is a function of distance that arises during movements of the observer’s head. The distance function consists in the fact that the retinal projections of objects closer to the eye, when the eyes and head move, are shifted proportionally more strongly than projections of more distant objects. Secondly, the projections of objects located closer and farther than the fixation point move in different directions.

Non‑visual cues of spatial depth can also be regarded as certain functions of distance, since the tension of the muscles that regulate the curvature of the lens and ensure their convergence, and accordingly the magnitude of the resulting proprioceptive sensations, are strictly proportional to the distance to the object fixed by the eyes.

By analogy with the disparity detector neurons that selectively respond to different values of retinal binocular parallax, it is logical to assume the existence of similar central detectors for all other distance functions that arise during the perception of objects on the two‑dimensional spaces of the retina and in the primary sensorimotor areas of the cortex.

Since different distance cues are always simultaneously involved in real processes of object perception, the central parts of the brain must integrate excitations from different detector systems of distance. In these integrative formations of the brain, the entire space accessible to the perception of the given organism must be “embodied”: each point of the surrounding space should correspond to a strictly defined group of selectively tuned distance detectors in these formations (Sokolov, 2003). A factual confirmation of such correspondence can be considered the neurons described in the literature that selectively respond to a specific location of objects in the visual field. Confirmation of the actual existence of a special brain area in humans, the activity of whose neurons “embodies” objective three‑dimensional space, may be clinical data on the so‑called neglect of one half of the visual field (more often the left) in local lesions of certain parts of the dorsal parietal region of the opposite hemisphere (Baars & Gage, 2007; Velichkovsky, 2006, pp. 343–345). Patients with such damage may eat only half of the food on their plate or apply makeup to only half of their face. When describing what they see in front of them, they completely ignore (“do not see,” “pay no attention to”) all objects located in that half of space that projects to the damaged hemisphere. The fact that it is specifically spatial perception that is lost here is proved by special tests demonstrating the ability of such patients to see and distinguish individual objects in the “invisible” part of the visual field.

The complex hierarchically organized neuronal system for reflecting space is designed to organize the goal‑directed spatial behavior of animals and humans. The central detector neurons of this system, excited by target objects located at different distances from the body of the animal or human, must send impulses of different structure and intensity to the neurons of the muscular system that perform movements. Such impulses should ensure an accurate reproduction, in the direction, intensity, and duration of movements (reaching and grasping objects, targeted jumps, approaching distant objects, etc.), of the parameters of the real objective space in which they are performed. How exactly such, in the words of Sechenov (1947), coordination of movements with sensation occurs, is not known today. That is a matter for the future.

The use of the difference in excitations on the plane of two‑dimensional receptors arising from differences in the propagation speed of different wave radiations coming from objects or from differences in their points of application, which is a function of distance, appears to be a universal method, found in evolution, for reflecting the third dimension of space. As Bickerton (2009) notes, recent research has added the most intriguing data on how bees measure distances, namely that they compare the speeds at which images of the landscape cross their field of vision during flight.

This universal method of reflecting the distance and distances to objects has received an impressive concrete embodiment in the organization of the spatial behavior of bats based on echolocation (Schiffman, 2001).

The essence of echolocation is that the bat emits ultrasonic signals into the surrounding space, and its auditory system perceives both the original signals and their reflection from surrounding objects. The difference in the time of perception of the first signal and its return serves as a very accurate and reliable cue of the distance to the object, since it is a function of it. The difference in the time of occurrence of two excitations in the bat’s auditory system – the first caused by the original sound, the second by the reflected sound – is registered by detector neurons selectively tuned to specific time intervals between these two receptor excitations. Altogether, this auditory and detector system is a reliable determinant of the distance from the bat’s body to the surrounding objects.

In addition to bats, whose neural mechanisms of echolocation have been well studied, echolocation ability is present in dolphins and some birds. There is evidence that this distance function can be used for spatial orientation by blind people. The literature reports a striking fact: a naturally blind horsewoman, winner of many competitions, had the ability to go around corners and fit into steep turns of the track, based on perceiving the difference in arrival time of the original and reflected sounds produced by the horse’s hooves (Schiffman, 2001).

The factual data obtained in studying the mechanisms of reflection of spatial depth and distance of objects in humans, scorpions, and bats show that it can be carried out on the basis of different sensory modalities. Accordingly, the “neural embodiment” of three‑dimensional space in the system of specific detector neurons can be not only visual, as in humans. It can be vibrational, as in the scorpion, or auditory, as in the bat and the blind horsewoman. But in all cases, the same objective space (within the limits accessible to the sense organs of each species) is represented in different nervous systems, and equal distances to objects in all cases are reproduced (recovered, find objective expression) in the same extension (the same length) of goal‑directed movements toward them.

Based on the above, we can to some extent imagine what it is like to be a bat. As is known, that is the title of a widely discussed article by Nagel (1974).

Chalmers (1996) rightly believes that the development of neuroscience methods will certainly make it possible to some extent to approach the understanding of what it is like to be a bat. He writes that neuroscience will have to find out what kind of information the bat has access to, what discriminations it can make, and how it uses this information, and that in the end we should be able to draw a detailed picture of the structure of awareness that is characteristic of the bat’s cognitive system. Of course, he writes further, we will not know everything about what it is like to be a bat, but we will know not so little.

If we concretize Chalmers’ (1996) words about the detailed picture of the structure of awareness that is characteristic of the bat’s cognitive system in accordance with the factual data of neurophysiology, we can consider that we understand in principle how objective space is represented in its perceptual system. And this, indeed, is not so little. But we can learn even more. We could ask a blind horsewoman (or any other blind person who has mastered a similar method of orienting in space) to describe how she orients herself in space, how she represents it to herself, what sensations tell her about distances to objects and between them. Then we would have both an objective and a subjective description of the auditory form of reflection (embodiment) of space in the observer’s nervous system and, consequently, could approach even closer to understanding what it is like to be a bat.

The thesis that the previous text has been devoted to substantiating is that objective three‑dimensional space receives its topical three‑dimensional embodiment in the nervous system of all living beings capable of orientation in space. This embodiment is such that each point of objective external space occupied by some object corresponds to a strictly defined group of neurons of the internal psychophysiological space (Sokolov, 2003). Activation of certain groups of such neurons in response to afferentation from objects located at the corresponding point of space can cause various kinds of unconditioned, conditioned, and voluntary motor reactions directed at these objects, leading to adequate spatial behavioral interaction with those objects.

As we can see, for understanding the mechanisms of sensory perception of space and the spatial behavior of living beings based on it, no additional ideas about the subjective representation of space in consciousness are required. The facts are well described without recourse to the concept of consciousness, to the concept of conscious subjective experiences. All our own introspective experience undeniably shows that within the space close to us, we constantly perform many acts of spatial behavior, without being aware either of the acts themselves, or of the stimuli that cause them, or of their position in space. These acts are unconscious. This does not mean that they are not mental. They are acts of mental activity because they are based on the reflection of reality, on the functioning of an internal map of external three‑dimensional space built in the brain. But they do not require the participation of consciousness in the sense of the givenness of external space to the subject himself. The spatial behavior of the bat is a vivid example.

It has already been said above that consciousness in the form of subjective givenness of objects to the subject is not an immanent integral property of mental images of objects. In order for the content of the psyche, represented in the system of neural brain “embodiments” of reality, to become conscious and “given to the subject,” new psychophysiological processes are required compared to those that operate at the level of sensory cognition and sensory‑perceptual regulation of behavior.

In psychology, ideas about such mental processes were developed in the theory of Brentano (see Yaroshevsky, 1976). According to Brentano, consciousness arises as a result of the action of special intentional mental acts coming from the subject and directed toward the object. Thanks to such acts, and only thanks to them, the images of objects represented in sensations, perceptions, and ideas become objects of consciousness.

At about the same time, in the middle of the 19th century, a similar idea received a hypothetical physiological interpretation by the German physician Kzolbe (cited in Ulrici, 1869). Kzolbe believed that the effects of the direct movement of the nerve current, caused by the action of external objects on the sense organs and coming to the corresponding brain centers, represent a kind of “image” of the external world. And when another repeated movement of the nerve current, coming from “internal” rather than external stimuli, arrives at the same brain points, then a connection of the external and our internal occurs, and that common quality of all types of human spiritual activity that is called consciousness is born. The general meaning of Kzolbe’s physiological hypothesis clearly coincides with Brentano’s psychological theory of consciousness (see Yaroshevsky, 1976).

At the present time, the idea of the repeated return of excitations to the brain projections of perceived signals from other parts of the brain associated with memory (hippocampus) and language areas, which is essential for the emergence of consciousness, has been developed in the theoretical conceptions of Edelman (1982, 2001) and in the experimental studies of Ivanitsky (1999, 2004). For Ivanitskii (1999, 2004), the characteristics of the late waves of the brain’s evoked potential to sensory stimuli, with latencies from 150 to 200 ms, are such a correlate of the mechanisms of consciousness. These characteristics, unlike those of early evoked potential waves, directly depend on the significance of the stimulus, on its motivational meaning, and correlate with indicators of decision‑making processes.

A strong argument in favor of the developed ideas is the key fact for Ivanitskii (1999) of the coincidence of the peak latencies of the late waves of the evoked potential (approximately 150 ms) and the time of occurrence of subjective sensations in humans upon the action of sensory signals (100–150–200 ms), as established in a number of experimental psychological studies. The same coincidence is noted by Edelman (1982), who, referring to the results of Libet’s research, writes about the significance of the fact that the minimal ‘activation period’ for awareness of a near‑threshold stimulus is about 200–500 ms. The same order of time (100–150 ms) characterizes the first signs of the emergence of local foci of increased excitability of the visual cortex at the points of address of stimuli which, according to verbal instructions, become objects of a person’s conscious cognitive activity. But a longer time (200–500 ms) is required for the final statistically significant local increase in excitability at these points of the visual cortex (Chuprikova, 1967, 2011, 2015).

Based on the ideas of Brentano (see Yaroshevsky, 1976), Kzolbe (see Ulrici, 1869), Edelman (1982, 2001), and Ivanitskii (1999, 2004), one must think that the phenomenal visual space given to us in our introspection should be the result of the action of the same physiological mechanisms. It should arise as a result of the integration of direct excitations in the cortical areas where the “brain embodiments” of objective three‑dimensional space are formed, and repeated excitations of neurons in the same areas arising from the implementation of intentional acts of consciousness coming from the subject and directed to the objects that actually fill the external three‑dimensional space.

After what has been said, a legitimate question arises: why is consciousness needed at all, if many adequate behavioral acts can be performed without its participation, solely on the basis of the general principle of “coordinating movements with sensation”? What role can and should the intentional acts of consciousness, which are based on the repeated return of excitations to the sensory‑perceptual neurons of the brain in whose activity objective reality is “embodied,” play in the organization of human behavior? Why is the phenomenal givenness of this reality needed?

In the most general form, the answer to this question with respect to humans is that all these processes are necessary for people to transmit to each other the contents of their mind by means of verbal (or gestural) signification of different elements of the brain’s “embodiments” of reality. By exchanging verbal signs, people exchange the mental contents associated with them. Since the content of sensory‑perceptual brain “embodiments” of reality under standard conditions of life and perception corresponds to that reality itself (is its neural‑brain double), people, by receiving information about the psyche of other people through verbal signs, thereby receive information about the reality represented in it. And this is necessary for organizing the productive joint activity of people in the natural and social environment. But in order to signify the content of one’s psyche (to connect it with specific signs), a person himself must first gain access to it. It is for this purpose that the mechanisms of the repeated return of excitations to the brain projections of perceived objects have been developed in anthropogenesis. Thanks to them, the content of the psyche, in the form of its rich phenomenal picture, is disclosed to the subject (appears before him) and, by linking its elements with specific verbal signs, can be transmitted to other people. For more details, see Chuprikova (1985, 2010, 2015).

However, one must think that the mechanism of repeated return of excitations to the sensory‑perceptual areas of the brain from other areas, characteristic of humans, has more ancient evolutionary prerequisites, as is assumed by Edelman’s (1982, 2001) theoretical model of brain function. It is this kind of mechanism that underlies the well‑developed orienting reflexes in higher animals, which Pavlov called the “What is it?” reflexes. In the structure of orienting reflexes, one can see, first, a clear intentional directedness of the animal’s psyche toward a specific object, leading to its extraction from the background and its study. Second, it has been established that this directedness, in the form of activating excitations locally addressed to the projections of the given object, is caused not by the properties of the object as such, but by internal signals of mismatch between incoming sensory afferentation and the neural model of the stimulus established in memory (Sokolov, 2003). From this we can conclude that all animals that have well‑expressed orienting and, even more so, orienting‑investigative reflexes possess an analogue of human consciousness, although, of course, less developed and differentiated in its content

Conclusions

The approach to solving the psychophysiological problem presented in this article coincides in its main general features with the approach of Edelman (2001), who considers it necessary to draw a fundamental distinction between primary and higher‑order consciousness. What Edelman calls primary consciousness is referred to in this article as sensory reflection of reality, consisting in the formation of brain “embodiments” of various objects and their properties, cognized through the sense organs, while higher‑order consciousness is simply called consciousness. Edelman (2001) briefly outlines his conception by drawing a distinction, which he believes is fundamental, between primary and higher order consciousness. He explains that primary consciousness is the state of being mentally aware of things in the world – of having mental images in the present. It is what some animals that do not use special linguistic means or special means for transmitting meanings presumably possess. In contrast, higher order consciousness includes the recognition by a thinking subject of his or her own actions or preferences. Edelman adds that we are aware that we are aware.

In Edelman’s (2001) formulation, the proposed research program consists of the following: first, we must build a model for primary consciousness, then build a model for higher order consciousness on top of it, and then begin to test the connections of each with human phenomenal experience. He further states that this program must explain how primary consciousness evolved, and then show how higher order consciousness was born from it.

The implementation of such a program requires a clear logical distinction between the extended‑material neural activity of the brain and the content embodied in it that relates to reality existing outside the brain. Among the tasks of concrete research on the path to implementing this program, the following can be named.

1. Detailed elucidation of what exactly the brain “embodiments” of various objects of reality and their properties, which are cognized through the sense organs and are carriers of mental awareness of things and phenomena in the world, consist of and how they are formed in phylo‑ and ontogenesis (physiologically, biochemically, structurally). In this article, a version of solving this problem has been considered using the example of the neurophysiological mechanisms of mental awareness of the surrounding three‑dimensional space in animals and humans.
2. Identification of the specific form in which the contents of the brain “embodiments” of reality are transmitted to the central neurons of the executive organs, ensuring adaptive coordination with sensation (and, consequently, with the conditions of the surrounding world) of motor acts, as well as of many other bodily reactions (vocal imitation, secretion of digestive juices corresponding to the quantity and quality of food acting on the taste receptors of the tongue, reproduction by the skin of some animals of the color characteristics of the surface on which they are located).
3. Identification of how, during the implementation of a person’s intentional acts directed at objects (which are based on the processes of repeated centrifugal arrival of excitations to the primarily excited sensory‑perceptual areas of the brain), these excitations “read” the contents of the sensory brain “embodiments” of reality, the results of which find expression in the person’s verbal (or gestural) reports. On this path, the problem of elucidating the physiological nature, formation, and ontogenetic development of the human self, as the agent that has access to the “embodiments” of various contents of reality being formed in the projection areas of the brain, and thereby can, through verbal (and gestural) signs, transmit these contents to other people, inevitably arises in full measure.

References

1. Baars, B. J., & Gage, N. M. (Eds.). (2007). Cognition, brain, and consciousness: Introduction to cognitive neuroscience. Academic Press.
2. Bickerton, D. (2009). Adam’s tongue: How humans made language, how language made humans. Hill and Wang.
3. Chalmers, D. J. (1996). The conscious mind: In search of a fundamental theory. Oxford University Press.
4. Chuprikova, N. I. (1967). The word as a factor of control in human higher nervous activity. [Slovo kak faktor upravlenija v vysshej nervnoj dejatel’nosti cheloveka]. Prosveshchenie.
5. Chuprikova, N. I. (1985). The mind and consciousness as a function of the brain. [Psihika i soznanie kak funkcija mozga]. Nauka.
6. Chuprikova, N. I. (2009). Theory of space perception: Reflection of depth, distances, and directions by their functions on the receptor plane. In V. A. Barabanshchikov (Ed.), Contemporary psychophysics(pp. 82–91). Institute of Psychology RAS. [Teorija vosprijatija prostranstva: Otrazhenie glubiny, rasstojanij i napravlenij po ih funkcijam na ploskosti receptorov. In V. A. Barabanshchikov (Ed.), Sovremennaja psihofizika (pp. 82–91). Institut psihologii RAN].
7. Chuprikova, N. I. (2010). On the way to a materialistic solution of the psychophysical problem: From Descartes’ dualism to Spinoza’s monism. Voprosy Filosofii, (8), 110–121. [Na puti k materialisticheskomu resheniju psihofizicheskoj problemy: Ot dualizma Dekarta k monizmu Spinozy].
8. Chuprikova, N. I. (2011). Verbal semantic control of the visual system in acts of conscious cognitive activity. In V. A. Barabanshchikov (Ed.), Contemporary experimental psychology(Vol. 2, pp. 207–220). IPRAN. [Verbal’no-smyslovoe upravlenie rabotoj zritel’noj sistemy v aktah soznatel’noj kognitivnoj dejatel’nosti. In V. A. Barabanshchikov (Ed.), Sovremennaja jeksperimental’naja psihologija (Vol. 2, pp. 207–220). IPRAN].
9. Chuprikova, N. I. (2015). The mind and mental processes: A system of concepts of general psychology. Yazyki Slavyanskoj Kul’tury. [Psihika i psihicheskie processy (Sistema ponjatij obshhej psihologii)].
10. Chuprikova, N. I. (2016). Spinoza’s monism as a basis for a materialistic solution of the psychophysiological problem. Voprosy Psikhologii, (6), 3–19. [Monizm Spinozy kak osnova materialisticheskogo reshenija psihofiziologicheskoj problemy].
11. Crick, F. H. (1979). Thinking about the brain. Scientific American, 241(3), 219–232. https://doi.org/10.1038/scientificamerican0979-219
12. Edelman, G. (1982). Group selection and phasic reentrant signaling: A theory of higher brain functions. In G. Edelman & V. Mountcastle (Eds.), The mindful brain: Cortical organization and the group-selective theory of higher brain function(pp. 51–100). MIT Press.
13. Edelman, G. (2001). Consciousness: The remembered present. Annals of the New York Academy of Sciences, 929(1), 111–122. https://doi.org/10.1111/j.1749-6632.2001.tb05711.x
14. Frolov, Yu. (2002). How the scorpion finds its prey. Nauka i Zhizn’, (5), 23–24. [Kak skorpion nakhodit zhertvu].
15. Galperin, P. Ya. (1992). Preface. In P. Ya. Galperin & A. N. Zhdan (Eds.), History of psychology: Texts(pp. 3–4). Moscow State University Press. [Predislovie. In P. Ya. Galperin & A. N. Zhdan (Eds.), Istorija psihologii: Teksty (pp. 3–4). Izdatel’stvo Moskovskogo universiteta].
16. Ivanitskii, A. M. (1999). The main riddle of nature: How subjective experiences arise from brain processes. Psikhologicheskii Zhurnal, 20(3), 93–104.
17. Ivanitskii, A. M. (2004). Natural sciences and the problem of consciousness. Vestnik rossijskoj akademii nauk, 4(8), 716–723.
18. Lange, N. N. (1922). Psychology: Basic problems and principles. Mir Publishing House.
19. Leontiev, A. N. (1975). Activity, consciousness, personality. [Dejatel’nost’, soznanie, lichnost’]. Politizdat.
20. Nagel, T. (1974). What is it like to be a bat? The Philosophical Review, 83(4), 435–450. https://doi.org/10.2307/2183914
21. Nagel, T. (1998). Conceiving the impossible and the mind-body problem. Philosophy, 73(3), 337–352. https://doi.org/10.1017/S0031819198000035
22. Nagumanova, S. F. (2007). Does the break in the modern interpretations of psychic exist? Voprosy filosofii, (1), 90–105.
23. Schiffman, H. R. (2001). Sensation and perception. John Wiley & Sons.
24. Sechenov, I. M. (1947). Selected philosophical and psychological works. [Izbrannye filosofskie i psihologicheskie sochinenija]. Gospolitizdat.
25. Sechenov, I. M. (1952). Physiology of nerve centers. [Fiziologija nervnyh centrov]. Academy of Medical Sciences of the USSR.
26. Sokolov, E. N. (2003). Perception and the conditioned reflex: A new view. [Vosprijatie i uslovnyj refleks: Novyj vzgljad]. UMK “Psikhologiya”; Moscow Psychological Social Institute.
27. Tolman, E. C. (1932). Purposive behavior in animals and men. The Century Co.
28. Ulrici, H. (1869). Body and soul foundations of human psychology(Trans.). A. M. Kotomin Publishing House.
29. Velichkovsky, B. M. (2006). Cognitive science: Fundamentals of the psychology of cognition(Vol. 1). Smysl; Academy. [Kognitivnaja nauka: Osnovy psihologii poznanija (Vol. 1). Smysl; Akademija].
30. Yaroshevsky, M. G. (1976). History of psychology. [Istorija psihologii]. Mysl’.