Thw Working Brain function and localization

AR Luria (1973)

Preface-- "Are man's gnostic processes and motivated actions the result of the work of the whole brain as a single entity, or is 'the working brain' in fact a complex functional system embracing different levels and different components each making its own contribution to the final structure of mental activity." (p.11).



Seld criticizes in advances lack of data on "minor hemisphere" and medial corticobasal structures.



Chapter one cites Broca's postulate based on his cases that the "posterior third of the left inferior frontal gyrus is the 'centre for the motor images of words' identifying the left hemisphere in righthanders as the dominant hemisphere for language. Cites Wernicke that the posterior third of the STG is 'the centre for the sensory images of words' or the 'centre for understanding of speech ' (Wortbegriff). In the "splendid 70's" ie 1870's, and for a half century, there was an attempt to "localize complex psychological processes in local areas of the brain" p.23. However, Luria state (p.25) that "without denying the obvious fact that elementary physiological 'functions' (such as cutaneous sensation, vision, hearing, movement) are represented in clearly defined areas of the cortex, these investigators [Monakow (1914), Head (1926), Goldstein (1927, 1944, 1948)]expressed valid doubts about the applicability of this principle of 'narrow localization' to the brain mechanisms of complex forms of mental activity.

"They therefore postulated that the complex character of "semantics" (Monakow) or "categorical behavior " (Goldstein) are the result of activity of the whole brain rather than the product of the work of local areas of the cerebral cortex... dependent more on the mass of the brain involved than on participation of specific zones of the cerebral cortex (Goldstein, 1944, 1948). ... (Luria then refers to) the decisive role of mass in the performance of mental activity, which have repeatedly burst forth throughout the history of the study of brain as the organ of mind." (cites Flourens, 1824, Goltz 1876-84, Lashley, 1929).

p.27 Reexamination of the concept of 'function'
"Those investigators who have examined the problem of the cortical 'localization' of elementary function by stimulating or excluding local brain areas have understood the term 'function' to mean the function of a particular tissue... when we speak of the function of digestion or the function of respiration it is abundantly clear that this cannot be understood as the function of a particular tissue..the whole of this process is carried out, not as a simple function but as a complete functional system, involving many components belonging to many different levels of the secretory, motor and nervous apparatus. Such a functional system (the term introduced and developed by Anokhin, 1930, 1940, 1949, 1963, 1968a, 1972) differs not only in the complexity of its structure, but also in the mobility of its component parts... for example,(in respiration) if the diaphragm ceases to act, the intercostal muscles are brought into play... THE CONCEPT OF 'FUNCTION' AS A WHOLE FUNCTIONAL SYSTEM IS A SECOND DEFINITION DIFFERING SHARPLY FROM THE DEFINITION OF A FUNCTION AS THE FUNCTION OF A PARTICULAR TISSUE. WHEREAS THE MOST COMPLEX AYTONOMIC AND SOMATIC PROCESSES ARE ORGANIZED AS 'FUNCTIONAL SYSTEMS' OF THIS TYPE, THIS CONCEPT CAN BE APPLIED ON EVEN STRONGER GROUNDS TO THE COMPLEX 'FUNCTIONS' OF BEHAVIOR." Further cites movement, example of Bernshtein, and Lashley mouse removed cerebellum and mouse achieved motor goals by different task, going head over heels.

p.30 Revision of the concept of localization
again, respiration "Pavlov, when discussing the notion of a respiratory centre, was compelled to recognize that 'whereas at the beginning we thought this was something the size of a pinhead in the medulla, now it has proved to be extremely elusive, climbing up into the brain and down into the spinal cord, and at present nobody can draw its boundaries accurately."

"The higher forms of mental processes have a particularly complex structure; they are laid down in ontogeny. Initially they consist of a complete, expanded series of manipulative movements which gradually have become condensed and have acquired the character of inner mental actions (cites Vygotsky 1956, 1960, Galperin 1959). As a rule, they are based on an external system of aids, such as language, the digital system of counting, formed in the process of social history, they are mediated by them, and cannot in general be conceived without their participation (Vygotsky); they are always connected with this reflection of the outside world."

"Two facts sharply distinguish the human brain (p31)... higher forms of conscious activity are based on certain external mechanisms (good examples are the knot we tie in our handkerchief so as to remember something essential, a combination of letters we write so as not to forget an idea, or a multiplication table) these external aids or historically formed devices are essential elements in the establishment of functional connections between the individual parts of the brain, and that by their aid, areas of the brain which previously were independent become the components of a new functional system. THIS CAN BE EXPRESSED MORE VIVIDLY BY SAYING THAT HISTORICALLY FORMED MEASURES FOR THE ORGANIZATION OF HUMAN BEHAVIOR TIE NEW KNOTS IN THE ACTIVITY OF MAN'S BRAIN, AND IT IS THE PRESENCE OF THESE FUNCTIONAL KNOTS, OR , AS SOME PEOPLE CALL THEM, NEW FUNCTIONAL ORGANS (cites Leonti'ev 1959)...

"The second distinguishing feature of the localization of higher mental processes in the human cortex is that it is never static or constant, but moves about essentially during development of the child and at subsequent stages of training... any complex activity is at first expanded in character and requires a number of external aids for its performance, and only later does it gradually become condensed and converted into an automatic motor skill.

(For example, in writing) the initial stages require the memorization of the graphic form of every letter, through a chain of isolated muscle impulses, each of which is responsible for one element of the graphic structure... with practice, the structure is radically altered and writing is converted into a single kinetic melody... In the course, it is not only the functional structure of the process which is changed, but also naturally, its cerebral organization." The participation of the auditory and visual areas of the cortex, essential early, is no longer necessary in its later stages, and the activity starts to depend on a different system of concertedly working zones (cites Luria, Smernitskaya, and Tubylevich, 1970).