Some Functional Investigative Problems. The Problem of the Dominant Hemisphere. Historical Survey. Language Sounds and the Hearing of Speech. Acoustic Agnosia and Sensory Aphasia. Acoustic-Mnestic Aphasia. Disturbances of Intellectual Processes with Temporal Lesions. Disturbed Tactile Perception and Tactile Agnosia. Spatial Disorientation and Constructive Apractagnosia.
Higher Cortical Functions in Man by Alexandr Romanovich Luria, Paperback | Barnes & Noble®
Disturbances of Arithmetical Operations and the Syndrome of Acalculia. Disturbances of Intellectual Processes. Disturbances of the Afferent Basis of Voluntary Movement. Afferent Kinesthetic Apraxia. Disturbances of the Kinesthetic Basis of Speech. Afferent Kinesthetic Motor Aphasia.
HIGHER CORTICAL FUNCTIONS IN MAN
Disturbances of the Kinetic Structure of Speech. Efferent Kinetic Motor Aphasia. It was at this time that Virchow put forward the notion that the organism can be regarded as a "cell state" consisting of units that are the primary carriers of all its properties. Virchow's ideas were taken up by Meynert , who gave the first accurate account of the cell structure of th e cerebral cortex. In the face of the tremendous complexity of the structure of the human cerebral cortex, Meynert felt that the concepts in the field of cellular physiology could be transferred to this new field, and he began to regard the cortical cells as carriers of particular mental processes.
With the existence of such vast numbers of these vacant cells, impressions arriving in succession find carriers in which. The time with which we are concerned was one of great and decisive scientific achievement. In the 's, which Pavlov called "an outstanding epoch in the physiology of the nervous system" Complete Collected WorAs, Vol.
In , Fritsch and Hitzig, by stimulating the cerebral cortex of a dog with an electric current, showed for the first time that stimulation of certain cortical areas subsequently found to be those containing pyramidal Betz cells was followed by contraction of certain muscles. These experiments demonstrated that the cerebral cortex contains isolated "motor centers," a finding that was later confirmed by experiments on monkeys and, finally, by investigations in man.
Almost simultaneously with this research, the Kiev anatomist Betz discovered giant pyramidal cells in the cortex of the anterior central gyrus, and he associated them with the motor function. The discoveries of Fritsch and Hitzig, on the one hand, and of Betz, on the other, providing a factual basis for clinical observations, prompted a series of physiological experiments in which various areas of the cerebral cortex were extirpated in animals and the subsequent behavioral changes studied.
Among these investigations were the well-known ones of Munk , who found that after extirpation of the occipital portion of the brain a dog could still see but had lost the power of visual recognition of objects, and those of Hitzig , Ferrier , , Bianchi ,and others who observed gross disturbances of "attention" and of "intellectual activity" in animals after extirpation of the anterior divisions of the brain.
The discovery of the highly differentiated structure of the cerebral cortex and of the possibility of strict differentiation of function between its various parts may be counted among the great achievements of science. Accepting these discoveries as proof of the existence of distinct cortical "centers" for various motor or sensory functions, research workers now began to relate more complex mental functions to particular areas of the cortex with far more confidence than hitherto.
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At the close of the nineteenth and the beginning of the twentieth centuries, the neurological literature was replete with case reports of disturbances in complex mental processes of circum- scribed areas of the cerebral cortex, produced by lesions. The observers of these cases did not content themselves with describing the symptoms but also concluded that the corresponding areas of the cerebral cortex are the "centers" for the corresponding impaired functions.
In this way it began to be taught that not only are visual, auditory, and tactile perception localized in the cerebral cortex, but that such complex mental processes as "numbM" sense," "counting," "reading," "active ideation," and "volitional action," as well as even more complex forms, obviously social in origin, such as the "personal and social ego," are also localized. The fruit of these attempts to. He sided with the "topistic" teaching of o.
Vogt l, the founder of modern cytoarchitectonics, who postulated that the brain as a whole is composed of small organs "Kleinorgane" , and that each organ is the seat of a particular faculty. These views were subsequently embodied in the basic textbooks on neurology, such as that of Nielsen published in the United States. The suggestions that different areas of the cerebral cortex are highly differentiated in their structure and that complex mental functions are not uniformly related to the various areas of the brain were basically very progressive.
They stimulated the more careful study of the brain and its functions. Nevertheless, the idea that highly complex mental phenomena may be localized in circumscribed areas of the cerebral cortex and that the circumscribed area responsible for a particular function can be directly deduced from a symptom naturally continued to arouse deep misgivings.
For this reason, a century after the impact of the views of Meyer and Haller. At the time that Wernicke demonstrated the importance of the cortex of the left temporal lobe in man for speech, that Fritsch and Hitzig obtained a specific effect from stimulation of the motor area of the cortex, and that Munk observed a disturbance in visual recognition after destruction of the occipital region in a dog, the eminent German physiologist Goltz conducted a series of new experiments in which he extirpated different areas of the cerebral cortex in dogs.
Goltz determined the results of his experiments by observing the changes in the animals' general behavior. After extirpation of different areas of the cerebral hemispheres, the animals developed marked disturbances of behavior, which Goltz interpreted to be the reaction of the brain as a whole. These disturbances subsequently disappeared, the functions were restored, and only a slight awkwardness of movement and lack of coordination remained, the latter being regarded by Goltz as a manifestation of a "general lowering of intellect.
Flourens, working with birds, namely, that any part of the brain is associated with the formation of will, sensations, ideas, and thoughts, and that the degree of loss of function is directly and entirely dependent on the size of the lesion. As stated, Goltz limited his observations to the animal's general response to extirpation, without differentiating among the defects that developed.
Moreover, he used psychological terms of excessively broad meaning, such as "will" and "intellect. Nevertheless, his great merit lies in the fact that by referring to dynamic factors such as the "general reaction of the brain" and recognizing the great plasticity of the brain substance at a time when the concept of narrow localization was flourishing he directed attention to the activity of the brain as an entity.
It is interesting that Goltz's conclusions did not arouse much sympathy at the time of their publication, yet half a century later almost the same arguments were employed by Lashley After extirpating different areas of the brain in rats and observing the changes in their behavior while they were in a maze, Lashley concluded that a particular type of behavioral disturbance cannot be ascribed to a defect of a particular area of the brain, that the degree to which skilled movement is impaired is directly related to the mass of brain extirpated, and that different areas of the cerebral cortex are equipotential in relation to complex functions.
According to Pavlov, these attempts to interpret the results of extirpation of isolated areas of the brain by using the undifferentiated concepts of psychology are basically unsound. However, Lashley's principal conclusions, in support of the anti localization doctrine, were widely welcomed because they reflected a new stage in the development of psychology and correlated new psychological ideas-very different from the classical associationism-with brain structure.
Meanwhile many psychologists, partially influenced by the ideas of contemporary physics but more so by the idealistic phenomenology advanced by the so-called Wiirzburg school, abandoned the mechanistic concepts of the classical associationism and began to regard mental phenomena as integrated processes taking place in a particular "field" and subordinated to "structural" laws.
These laws, elaborated in considerable detail by the Gestalt school of psychologists, were extremely formal. Discarding the analytical methods used in the natural sciences, the adherents of Gestalt psychology took what, in fact, was a step backward from the previous stage of development of psychological science. The "integral" or "dynamic" ideas of the new psychology, requiring correlation with brain structure, took support from Lashley's antilocalization. In these hypotheses, functions labeled on the basis of generalized psychological concepts were correlated as before, directly and without physiological analysis, with brain structure.
It is true that "integrated behavior" was correlated with the "integrated brain.
Higher cortical functions in man
Any suggestion of a differential anatomic-physiological analysis of the structure of the brain was rejected just as decisively as had been the differential analysis of the animal's skills or habits. Rather than make a detailed study of the cerebral apparatus, these investigators were content to use analogies on the relationships of structure and substrate as formulated in physics and the general morphogenic principles embodied in embryology.
The new form of antilocalizationism quickly spread beyond the confines of research on the cerebral mechanisms of animal behavior to clinical medicine. It gradually developed into an important force opposing the classical ideas of localization. It is therefore necessary to consider their development in greater detail.
During the 'S, the celebrated English neurologist Hughlings Jackson, who gave the first account of epileptic fits arising on a localized basis, formulated a series of principles in sharp opposition to the contemporary ideas of narrow localization. These principles, destined to play an important role in the subsequent development of neurological thinking, were enunciated by Jackson in the course of a discussion with Broca soon after the latter had published his observations. During the following decades, however, these principles were overshadowed by the successful progress of the localizationist's views, and it was not until the first quarter of the twentieth century that these ideas came to be widely accepted.
It should be noted that Jackson's investigations, which were cited some 50 years after they were performed by Pick , Head , and Foerster , were first published in summary form only in in England and again in in the United States.
The occurrences on which Jackson based his theories were irreconcilable with Broca's fundamental ideas and with the concepts proceeding from the belief in the cellular localization of functions. During his studies of motor and speech disturbances accompanying local brain lesions, Jackson observed a phenomenon that, at first glance, appeared paradoxical, namely, that a lesion of a circumscribed area of the brain never leads to the complete loss of a function.
A patient with a lesion of a particular zone of the cortex frequently cannot perform a desired movement or repeat an arbitrarily given word, although he may be able to do so involuntarily, i. A case later described by Cowers-in which a patient, when asked by the doctor to say the word "no," replied: "No, doctor, I never can say 'no'!
On the basis of occurrences such as these, Jackson elaborated a general. In his opinion, every function performed by the central nervous system is not the domain of a narrowly circumscribed group of cells that serve as what might be termed a "depot" for this function. Rather, each function has a complex "vertical" organization.
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It is first represented at a "low" spinal or brain-stem level, re-represented at the "middle" level of the motor or sensory divisions of the cerebral cortex, and represented for the third time re-re-represented at a "higher" level, which Jackson considered to be the frontal divisions of the brain. Hence, according to Jackson, the localization of a symptom the impairment of a particular function accompanying a lesion of a circumscribed area of the central nervous system cannot in any way be identified with the localization of the particular function. The latter may emanate from the central nervous system in a much more complex manner and may have a completely different cerebral organization.
Jackson's contemporaries took an incorrect and biased view of his ideas. His hypothesis pertaining to the complex character and vertical organization of functions was many decades ahead of the development of science at that time, and for a long time it remained forgotten, having been confirmed only very recently. On the other hand, his declarations against the concept of narrow localization of functions in circumscribed areas of the cerebral cortex and his claims regarding the complex "intellectual" or "voluntary" character of higher psychological processes were soon adopted by the most idealistically oriented workers, who regarded these viewpoints as support in their stand against the materialistic sensualism of classical neurology.
In the period after , attempts were made to have mental processes be regarded as essentially complex, "symbolic" functions. The opinions held by the adherents of this doctrine clashed with the views inherent in narrow localizationism. Mental processes were looked upon as products of the activity of the brain as a whole, with cerebral localization entirely rejected.
All that could be said about human mental life was that it is a new, "abstract" type of activity, performed by the brain as the "instrument of the spirit. A similar attitude was taken by Kussmaul , who rejected the view that the material basis of memory is a special depot in the cerebral cortex, where images and ideas lie "neatly arranged on the shelves. It was at this time that Bergson , seeking to justify his frankly idealistic approach to mental activity, suggested that active dynamic schemes are the basic motive force of the mind, and contrasted them with material "brain memory.
These ideas also spread to neurology. They came to the fore in the writings of the noetic school of neurologists and psychologists Pierre Marie, ; van Woerkom especially , ; Bouman and Gninbaum, ; and Goldstein, , , The followers of this school held that the principal form of the mental process is "symbolic activity," put into operation as "abstract" schemes, and that every disease of the brain is manifested, not so much by a loss of the ability to carry out specialized processes as by a depression of this symbolic function or abstract orientation.
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These assertions brought about radical changes in the problems confronting neurologists at this later stage of scientific development. The analysis of the material basis of individual functions as the primary task of research was replaced by the description of the forms of depression of symbolic function or abstract behavior arising from any disease of the brain.
In practice, the investigation of the cerebral mechanisms of these disturbances now took second place. Once again having adopted the view that the brain works as a single entity and having related disturbances of the higher mental processes primarily with the size of the lesion and not with its locadon, these writers made a valuable contribution to the psychological analysis of the changes in cognitive activity accompanying local brain lesions; on the other hand, they greatly impeded research into the material basis of the cerebral mechanisms of mental processes.