VERY TECTONICS OF THE CEREBRAL CORTEX

From Big Medical Encyclopedia

VERY TECTONICS OF THE CEREBRAL CORTEX (hemicerebrums) — the division of science about a brain studying the principles of the general structure and space ratios in a cerebral cortex of nervous cells (cytovery techtonic dance), nerve fibrils (miyeloarkhitektonik), vessels (angioarchitecture), interneural bonds (synaptology) and a neuroglia (glioarkhitektonik). On the basis of very tectonic signs all surface of big cerebral hemispheres is divided into base units of various importance: main territories, or zones (zonae), area (regiones), subarea (subregiones), field (ageaa), subfields (subareae). And. to. of m gives the grounds for quality and quantitative standard of a differentiation of certain territories and bark in general in process both individual, and a phylogenesis. The very tectonics significantly differs from histology, the cut is a subject of studying generally thin structure of separate fabric elements, and the topographical ratios having the leading value for very tectonics in histology or are not considered at all, or play the subordinated role.

History

Very tectonic cards

should be considered the Initial stage of studying of local features of a structure of bark of hemicerebrums Dzhennari's opening (F. Gennari, 1782) strips in department of occipital area which in a crust, time carries the name area striata. Meynert (T. H. Meynert, 1868 — 1872) investigated bark of big cerebral hemispheres microscopically and divided it into five layers: molecular, outside granular, pyramidal, internal granular and layer of spindle-shaped cells. A number of specifications is brought in this description of layers in the subsequent; so, the first floor is divided by Lewis (R. Lewis, 1878) and Brodmann (K. Brodmann, 1907) layer V and VI (fig. 4), and Vogt (O. of Vogt) — on layers of V, VI and VII.

Works of the Kiev anatomist V. A. Bets (see) which opened colossal pyramidal cells in the field of the precentral crinkle and established value of this area as motive zone were of great importance, and also described a very tectonic structure and some other areas.

As a result of systematic studying of a structure of bark of hemicerebrums there were very tectonic cards made by Campbell (A. Campbell, 1905), Smith (E. Smith, 1907), Brodmann (1903—1909), S. Vogt and O. Vogt (C. Vogt, O. of Vogt, 1919 — 1920), Ekonomo and Koskinas (G. Economo, G. N. Koskinas, 1925), Ying volume of a brain of the USSR Academy of Medical Sciences (1949). Campbell's card is made on the basis of studying both cyto - and miyeloarkhitektonik of bark of hemicerebrums of the person, an orangutan, chimpanzee, dog, cat and pig. In bark of hemicerebrums of the person Campbell allocated about 20 fields. In Smith's cards division into fields was carried out on the basis of only macroscopic studying of cuts of bark. Brodmann on the basis of a cytovery tectonic research executed cards of a brain of the person, monkeys, semi-monkeys, predatory, rodents, insectivorous and wing-handed animals. The main borders of fields of a cerebral cortex of the person given by Brodmann match their borders on Campbell's card, but on Brodmann's card division more detailed. The card S. Vogt and O. Vogt which is based on studying miyeloarkhitektonik of bark of hemicerebrums gives division much more fractional. More fractional division, than Brodmann's card, also Ekonomo and Koskinas's cytovery tectonic card who divide all surface of hemicerebrums into seven shares gives, making the amendment that their cytovery tectonic borders do not match precisely the borders accepted by anatomy.

Fig. 1. Cytovery tectonic card of bark of a great brain (Institute of a brain of the USSR Academy of Medical Sciences). Outer surface of a hemisphere. Figures designated fields of new bark, by figures with letters — subfields of new bark (the characteristic of fields and subfields see in the text of article).
Fig. 2. Cytovery tectonic card of bark of a great brain (Institute of a brain of the USSR Academy of Medical Sciences). Inner surface of a hemisphere. Figures designated fields of new bark, by letters — ancient, old and intermediate bark. Figures with letters designated subfields of new bark (the characteristic of fields and subfields see in the text of articles).

The cytovery tectonic card Ying-that a brain (fig. 1 and 2) was made as a result of a sravnitelnoanatomichesky and ontogenetic research of bark of big parencephalons of the person. Evolutionary approach allowed to allocate five genetically isolated territories of bark (neocortex, a very cortex, a paleocortex, a periarchicortex and a peripaleocortex) from which two last — interstitial — are independent very tectonic units that was not considered in all previous cytovery tectonic cards. In the cytovery tectonic card Ying-that a brain remains for designation of fields of a new hole the digital nomenclature of Brodmann: alphabetic references are applied to areas of ancient, old and intermediate bark. But also in the card of new bark there were necessary known amendments to Brodmann's card. The parietal area, uniform at Brodmann, is subdivided on top and bottom.

In some cases on the basis of identification of thinner structure of various sites of bark the number of designations for fields of new bark is increased, but these designations keep communication with Brodmann's designations. So, the field designated by Brodmann as the field 37 is considered as a subarea of temporal area and the expert is divided into fields 37a, 37b, 37c, 37d, 37ab and 37.

The cytovery tectonics (neurocytoarchitectonica corticis)

in the course of embryonic development a wall of an end brain is differentiated as showed classical researches of Gis (W. His, 1904), on four main layers: 1) the maternal layer (matrix) consisting of dense accumulation of neuroblasts and spongioblasts adjoining directly to a cavity of a ventricle; 2) the light medine containing the migrating neuroblasts; 3) the cortical plate which is formed of accumulation of the migrating neuroblasts; 4) marginal layer poor in cells. But so fully the wall of an end brain is differentiated only on a side surface of a hemisphere where the cortical plate is expressed accurately and well separates from intermediate and regional layers.

It is new bark, or a neocortex (neocortex). On an inner surface of a hemisphere old bark, or a very cortex (archicortex) is located. The wall of an end brain differs in this area in an early stage of embryonic development in trace amount of cellular elements; the cortical plate of old bark is characterized also further by much weaker differentiation, than the cortical plate of a neocortex, though is separated, as well as there, a medine from a maternal layer. From new bark old bark separates the intermediate periarkhikortikalny zone having both in the course of ontogenetic development and at the adult obviously transitional character. On the basis of an end brain ancient bark, or a paleocortex (paleocortex) is located. In an embryogenesis all wall of an end brain in this zone is very wide since the maternal layer forms voluminous cellular accumulations in the form of the so-called ganglionic hillocks pressing in a cavity of ventricles here (further from these hillocks the striate body, anonymous substance and an amygdaloid nucleus form). The cortical plate of a paleocortex at early stages does not separate, and in post-natal ontogenesis only poorly separates (unlike new and old bark) from these cellular accumulations therefore ancient bark is called also semi-separated bark (cortex semiseparatus). Ancient bark as well as old, does not adjoin directly with new, and separates from it an intermediate zone — peripaleokortikalny, keeping as well as a periarkhikortikalny zone, in all development transitional character.

Fig. 3. Basis of a brain of a 5-month fruit of the person: 1 — bulbus olfactorius; 2 — gyrus olfactorius medialis; 3 — sulcus parahippocampi; 4 — gyrus parahippocampalis; 5 — uncus; 6 — sulcus rhinicus posterior; 7 — sulcus semianularis; 8 — gyrus ambiens; 9 — gyrus semilunaris; 10 — tuberculum olfactorium; 11 — insula; 12 — ligamentum diagonale; 13 — gyrus olfactorius lateralis; 14 — sulcus rhinicus anterior.

In general, thus, bark of hemicerebrums is divided into five main zones morphogenetic different from each other on the bookmark and ontogenetic development: ancient bark (paleocortex); old bark (very cortex); intermediate periarkhi-cortical zone and intermediate peripaleokortikalny zone; new bark (neocortex) (fig. 3).

Ancient bark, or a paleocortex

Ancient bark, or a paleocortex, has the least complex structure and is characterized by primitive structure of the cortical plate which is poorly separated and at the adult from subcrustal cellular accumulations. In phylogenesis it appears especially early, in the form of olfactory bark at selakhiya [H. Kuhlenbeck]. At animals are an olfactory hillock with a cortical plate (tuberculum olfactorium) which is very poorly separated from a head of a kernel (caput nuclei caudati) having a tail a part of ancient bark and diagonal area with the cortical plate which is not separating from the anonymous substance possessing large cells. The olfactory hillock occupies front department of the front made a hole substance (substantia perforata ant.), diagonal area — its back department and a paraterminal crinkle [gyrus paraterminalis (PNA)]. Also periamigdalyarny area with the cortical plate which is poorly separated from an amygdaloid nucleus (corpus amygdaloideum) which is located on an inner surface of a temporal share in its upper internal department is a part of ancient bark. The transparent partition (septum pellucidum) with especially strongly reduced cortical plate which is not separating from the maternal layer forming a kernel of a partition (nucleus septi) also belongs to ancient bark. At last, the most outside department of ancient bark at animals is made by prepiriformny area, a cortical plate the cut close approaches the islands of gray matter making a lower part of a fencing (claustrum). It occupies generally lateral olfactory crinkle (gyrus olfactorius lat.), limiting outside and in front the front made a hole space.

Old bark, or a very cortex

Old bark, or a very cortex, appears in the course of phylogenesis later, than ancient bark; at amphibians it is only planned, but at reptiles is expressed already very accurately and difficult differentiated on areas and fields. Unlike ancient bark, old bark possesses the cortical plate which is completely separated from a subcortex. At the same time it differs also markedly from new bark since remains also at the adult single-layer or only with poorly planned stratification. Are a part of old bark located in the depth of a gippokampovy furrow a hippocampus (hippocampus) with very large cells which is divided into a number of fields (subiculum, h1, h2, h3, h4, h5), and a gear crinkle (gyrus dentatus) with the cortical plate containing densely located small cells. indusium griseum (PNA) covering a corpus collosum, a cranked crinkle and a medial olfactory crinkle also belongs to old bark at animals [gyrus olfactorius med. (BNA)] and characterized by strongly reduced cortical plate, edges represents continuation of a kpereda of a cortical plate of a hippocampus.

Intermediate bark

the Intermediate bark appearing in phylogenesis along with new bark, i.e. at reptiles, and especially accurately differentiated at mammals, is divided into two zones as it separates new bark from ancient (a peripaleokortikalny zone) and from old bark (a periarkhikortikalny zone). The Peripaleokortikalny zone separating ancient bark from new bark occupies a lower part of the insular area, very small at the person, which is generally presented by formations of new bark. The Periarkhikortikalny zone separating old bark from new bark occupies a parahippocampal crinkle (gyrus parahippocampalis) and the most lower part of limbic area. On a parahippocampal crinkle the periarkhikortikalny zone is divided into presubikulyarny and entorinalny areas, and the last is differentiated on subareas and fields and finds very difficult stratification. Its layers arise, however, in much earlier terms, than layers of new bark, and have other origin and a structure.

New bark, or neocortex

New bark, or neocortex (synonym: gamogenetic bark of Brodmann, Vogt's isocortex), considerably surpasses in the area at the person all other territories of bark, combined, making about 96% of all surface of hemicerebrums. New bark appears for the first time in the course of evolution only at reptiles, but at them it is insignificant by the sizes and is rather simple on a structure (so-called side bark). New bark receives a typical multilayer structure only at mammals where at a certain stage of development (5 — 6 months of an antenatal life) it is split as Brodmann showed, on six layers, than differs markedly from heterogenous bark (ancient, old and intermediate bark) where there is no such stratification.

Gamogenetic new bark keeps a six-layer structure also at the adult (homotypic bark of Brodmann), but in some fields the number of layers either increases, or decreases (heterotypical bark of Brodmann).

Fig. 4. Cyto - and miyeloarkhitektonichesky layers of new bark. The main cytovery tectonic layers are designated by the Roman figures (underlayers — figures with letters); miyeloarkhitektonichesky layers are designated Arab (underlayers — figures with letters).

The following structure (fig. 4) is characteristic of the main layers of new bark. The layer I, molecular plates (lamina molecularis), on the origin does not belong to a cortical plate, and arises at the earliest stages of pre-natal development as a marginal layer of a wall of an end brain. At the adult it is very poor in cells.

The layer of II, an outside granular plate (lamina granularis externa), is characterized, on the contrary, by a large number of densely located cells. Cells belong hl. obr. to granular neurocytes (neurocytus granularis) having very small sizes, a roundish or angular form. In some fields, however, instead of grains in a layer of II there are small pyramidal neurocytes (neurocytus pyramidalis parvus); especially it is characteristic of formations of the precentral region — «a motive zone» (gyrus precentralis), the precentral crinkle and a paracentral segment (lobulus paracentralis) in its front department.

The layer of III, a pyramidal plate (lamina pyramidalis), consists generally of pyramidal neurocytes. The size of these cells mostly increases in the direction deep into so the layer of III in the majority fields breaks up to three underlayers: underlayer of III 1 with small pyramidal neurocytes (neurocytus pyramidalis parvus), underlayer of III 2 with average pyramidal neurocytes (neurocytus pyramidalis medius) and underlayer of III 3 , containing big pyramidal neurocytes (neurocytus pyramidalis magnus). However in some fields the layer of III is not divided into underlayers (half of the 17th occipital area), in some is divided into two underlayers, in some into four. Also strongly also the size of cells of a layer III changes from the field to the field. In some fields (e.g., in the field 17) they in general have the small sizes, in others can reach very big size, napr, in the field 18 on border with the field 17 where cells of an underlayer of III 3 gain in places «huge» character. Also density of distribution of pyramidal cells, and also character of their arrangement in the vertical direction is strongly changeable: in one fields they are located with radial tyazha, in others — more or less diffuzno.

The layer of IV, an internal granular plate (lamina granularis interna), consists of densely located small granular neurocytes of a round and angular form (neurocytus granularis parvus).

This layer is especially changeable and, being well-marked more or less homogeneous in homotypic fields, in heterotypical fields can either be absent, or be subdivided into underlayers. The example of heterotypical bark with disappearance of a layer of IV (agranular type) is represented by fields 4 and 6 of the precentral region (a nuclear zone of a motor analyzer). From such agranular type to well-marked granular type there is a number of transitions — there are fields where the layer of IV is only planned, and there are fields where it, though exists as the isolated layer, is very narrow. A classical example of heterotypical bark with splitting of a layer of IV is half of the 17th occipital area, representing a nuclear zone of the visual analyzer. The layer of IV breaks up here very accurately to underlayers of IVa, IVb, IVc.

The layer of V, a ganglionic plate (lamina ganglionaris), much less dense, than the layer of IV located over it, and a little less dense, than the layer of VI which is under it, consists generally of pyramidal neurocytes (neurocytus pyramidalis) among which also very big cells — huge pyramidal neurocytes — Bets's (neurocytus gigantopyramidalis) cells occur. It can be uniform, but is divided the most part into two underlayers. In the field of the 4th precentral region the layer of V breaks up to three underlayers, on average from which the colossal cells of Bets reaching considerable size are located (to 120 microns).

The layer of VI, a polymorphic plate (lamina multiformis), is divided into two underlayers — triangular, consisting preferential of triangular neurocytes (neurocytus triangularis), and spindle-shaped, consisting of spindle-shaped neurocytes (neurocytus fusiformis). O. Vogt allocates these underlayers as independent layers: layer of VI (lamina triangularis) and layer of VII (lamina fusiformis). Their structure variously in different fields. The kolonkoobrazny type of a structure is especially peculiar, at Krom of a cell of a layer of VI are located with columns (fields of occipital area, especially the field 17). The layer of VI or sharply separates from white matter, or passes into it gradually, without sharp border.

According to features of a structure both all diameter of a cortical plate, and its separate layers new bark is divided into a number of areas, each of which is subdivided in turn into a number of fields.

Occipital area (fields 17, 18 and 19) it is characterized in general by the small size of cells and their dense arrangement, very light layer of V, a kolonkoobrazny layer of VI, dominance on width of the upper floor of diameter of bark (layers of II, III and IV) over the first floor (layers of V and VI). The central department of occipital area forms the field 17 (area striata) occupying a shporny furrow (gyrus calcarinus) and parts of a wedge (cuneus) and a medial temporal and occipital crinkle (gyrus temporooccipitalis medialis) adjoining to it. The Melkokletochnost and a gustokletochnost are expressed in the field 17 especially sharply (a so-called koniocortex, or powdered bark). Very characteristic are the splitting of a layer described above IV on underlayers and especially sharply expressed kolonkoobrazny drawing of a layer VI. The fields 18 and 19 surrounding the heterotypical field 17 annularly belong to homotypic bark and on the structure make as if transition from the field 17 to fields of parietal and temporal areas, i.e. to fields 7, 39 and 37.

Upper (fields 5 and 7 with under - fields 7s, 7α and 7γ) and lower (the field 39 with subfields 39s and 39r and the field 40 with subfields 40s, 40 a shouting, 40i and 40r) parietal areas treat homotypic bark and are characterized by accurately expressed division of diameter of bark into six layers with well isolated outside and internal by granular layers. Also radial distribution of cells of a layer of III, a considerable gustokletochnost and small in general size of cells, and also gradual, in the direction to occipital area, reduction of dominance on width of the first floor of bark over upper are characteristic. The field 5 making front department of upper parietal area is characterized along with the specified signs existence of very big cells in a layer V, reminding pyramidal neurocytes (colossal cells of Bets) in the field of the 4th precentral region. The field 7 which does not have such cells differs, as well as the field 5, from fields 39 and 40 of the lower parietal area the big size of cells and their less dense arrangement.

Postcentral area (fields 3/4, 3, 1, 2 and 43) occupies a bottom and a back wall of the central furrow (sulcus centralis), and also a surface of a postcentral crinkle (gyrus postcentralis) and back department of a paracentral segment. The bottom of the central furrow is occupied with the field 3/4, a cut represents on the structure transition from postcentral area to the precentral region and is characterized at the same time by existence and an inner granular layer (a sign of postcentral area), and gigantopiramidalny neurocytes (Bets's cells) in a layer of V (a sign of the field of the 4th precentral region). On a back wall of the central furrow the field 3 which is characterized by especially small size of cells and abundance of small granular neurocytes, very big gustokletochnost, very light layer of V is located. In an upper part of a back wall of the central furrow and on a surface of front department of a postcentral crinkle the field 1 which is characterized by very clear split into six layers and markedly differing from the field 3 the considerable size of cells of layers III, V and VI is located. The field 2 adjoining behind the field 1 differs from it only in small details in a structure. The field 43 occupying operculum is a complex of structures from which only the central departments have typical signs of this area.

Precentral region (fields 4 and 6 with subfields 6a, 6r and boron) is located on a surface of the precentral crinkle and front department of a paracentral segment, on a front wall of the central furrow and on a surface of back department of upper and average frontal crinkles (gyrus frontalis sup. et med.) also it is characterized first of all by the fact that the layer of IV is not expressed, and the layer of II is expressed poorly or is absent. Characteristic signs are also weak otdelennost of layers from each other (weak horizontal striation), existence of especially eumorphic pyramidal neurocytes, a small gustokletochnost, big width of both all cortical plate, and its especially ground floor (layers of V and VI). The field 4 (area gigantopyramidalis) is characterized still by existence of gigantopiramidalny neurocytes in a layer of V which give to this field extremely typical look. The field 6 differs from the field 4 generally only in lack of colossal cells of Bets.

Frontal area includes in the structure many fields (5, 9, 46, 10, 11, 12, 44, 45, 47 (with subfields 47-1, 47-2, 47-3, 47-4, 47-5), 32 (with subfields 32/8, 32/9, 32/10, 32/12); from which the most back field 8 still reminds the precentral region since the layer of IV is hardly planned on a structure. However, unlike the field 6 which is located further kzad, in the field 8 this layer nevertheless is available. For the rest fields of frontal area are presented by homotypic bark with very clear division into six main layers.

Temporal area (an upper temporal subarea with fields 41, 41/42, 42, 22, 22/38 and 52, an average temporal subarea with fields 21 and 21/38, the lower temporal subarea with fields 20tc, 20l, 20b and 20/38 and a temporal and parietooccipital subarea with fields 37a, 37b, 37c, 37d, 37ab and 37 the expert) occupies all temporal share to a rhinal furrow (sulcus rhinalis) separating from it the parahippocampal crinkle covered with the intermediate bark delimiting new bark from old (entorinalny and presubikulyarny areas, E and Psb). Fields of temporal area have almost completely homotypic structure, well-marked granular layers and mostly well-marked radial striation, especially typical in some fields in a layer of IV which breaks up to peculiar columns. Bark in the tail of an upper surface of the temporal share hidden in a lateral (silviyevy) furrow (field 41 and 42) has a special structure. In the field 42 located closer to an exit to a free surface rather big cells in an underlayer of III attract attention along with the small densely located cells. The field 41 located in the depth of a lateral furrow has especially gustokletochny structure and belongs, as well as half of the 17th occipital area and half of the 3rd postcentral area, to powdered bark, or a koniocortex. To fields 41 and 42 afferent fibers of a medial cranked body (corpus genicula-tum med.) approach especially dense bunches, also dense bunches afferent fibers from a lateral cranked body approach the field 17 (corpus geniculatum lat.). These are nuclear zones of acoustical and visual analyzers.

Limbic area, occupying zone and parahippocampal crinkles, in the lower part (depth of a furrow of a corpus collosum) it is presented by the intermediate bark (peritektalny area) separating taenia tecta (old bark) from new bark, generally she is busy with fields of new bark (field 23, 23/24, 24, 25, 31, 31/32 and 24/32). In back department the limbic area has a six-layer structure, in front department it, as well as the precentral region, is occupied with agranular bark (absence is clear the expressed and isolated layers of II and especially to IV).

Insular area [an island (insula)] only in small lower part it is presented by the intermediate bark separating new bark from ancient bark. Generally insular area completely hidden in the depth of a lateral (silviyevy) furrow and forming its bottom, belongs to new bark (field 13 and 14). Its back department belongs to homotypic bark and is characterized by well-marked granular layers, the front department has, as well as fields of the precentral region and front department of limbic area, an agranular structure.

The size of a surface of the main zones and neocortical areas of a brain of the person in relation to a surface of a hemisphere is expressed by the following figures as a percentage (according to Institute of a brain).


The functional and biological importance of very tectonic characteristics of bark of hemicerebrums can be understood by hl. obr. at evolutionary approach to a problem of studying of strukturnofunktsionalny specifics of a brain of the person.

At a research of a brain in the ascending number of land mammals it is revealed that increase in a surface a hemisphere, complication of the drawing of furrows and crinkles corresponds to complication of the structural organization of a cortical plate. Studying of water mammals showed considerable development of big hemispheres at very low organization of a neocortex that can testify to a certain independence of evolution of signs of a very tectonic differentiation of bark of the size of a surface of hemispheres. Comparison of the hemispheres given to surface area (ancient, old, intermediate and new bark in the sum) and the weight of a brain of various representatives of mammals (a hedgehog, a kangaroo, an anteater, a dog, a pig, a tiger, a seal, macaques, a baboon, an orangutan, a chimpanzee, a dolphin ordinary, a dolphin of an afalin, a whale a financial shaft, the person) showed direct proportionality of surface area of hemicerebrums from the weight of a brain. Ratios of a surface of hemispheres and weight of a brain both at a hedgehog, and at a dolphin, and at the person same, despite the lack of furrows at a hedgehog and their abundance at a dolphin and the person. The percent of the area of the bark located in furrows (an intrasulkalny component) seeming to earlier evolutionarily significant was also depending on the weight of a brain (at a whale — 88,1, at a dolphin of an afalin — 85,0; at a dolphin ordinary — 78,6 and at the person only 64,8).

Similar ratios (directly proportional dependence of surface area of hemispheres on the weight of a brain) are accurately traced also in ontogenesis of cortical formations of a brain of the person. Therefore, neither the size of a surface of hemispheres, nor quantity of furrows and crinkles, an intrasulkalny component in itself can be signs to the high evolutionary organization of a brain yet.

Process of evolutionary changes of cortical territories of big cerebral hemispheres from the lowest mammals to the highest and the person consists in a tendency of divergent («multidirectional») development of zones, various on genesis. So, new bark in relative size to all bark considerably increases, and ancient bark obviously decreases. And if in the relative size of new bark of people it is almost not allocated from group of primacies and even concedes to a dolphin, then based on the ratio of the absolute area of new and ancient bark as to the indicator of the maximum deviations (IMD), considerably surpasses both primacies, and cetacea. The tendency of divergent development phylogenetic the latest and phylogenetic the most ancient structures within genetically isolated territories of a brain, inherent to all land mammals, reaches the maximum expression in a brain of the person (tab. 1).

In new bark in the ascending number of primacies the areas concerning the highest associative and integrative mechanisms (frontal, temporal, lower parietal) obviously increase, phylogenetic an ancient part of new bark (limbic area) relatively decreases, the projective zone of the visual analyzer (occipital area) also decreases and there is stable in all number of primacies, including the person, a precentral region connected by hl. obr. with motor functions (tab. 2).

The similar regrouping of fields, various on genesis, in the ascending number of primacies occurs within the certain areas which are obviously progressing (tab. 3), rather decreasing (tab. 4) and rather stable (tab. 5).

Quantification of structural changes of a brain in evolution of mammals reveals the specifics of a brain of the person consisting in the maximum expressiveness phylogenetic the latest and minimum — phylogenetic the most ancient educations within genetically isolated territories. Comparative study of ontogenesis of cortical formations of a brain of the person and a monkey showed considerable increase of a surface of parencephalons of the person in post-natal ontogenesis (the surface area of parencephalons of the newborn makes apprx. 20% of surface area of parencephalons of the adult), unlike a monkey, at a fruit the surface area of hemispheres makes a cut by the time of the birth apprx. 80% of surface area of an adult individual (I. A. Stankievich, 1964).

Besides, changes of PMD (tab. 6) at a fruit of the person and a fruit of a monkey in the first half of pregnancy have the character, general for primacies, whereas before the birth the sharp jump of PMD of a brain of the person corresponds to emergence of specifically «human» signs of a differentiation of a neocortex (subfields).


Miyeloarkhitektonika (myeloarchitectonica corticis)

Miyeloarkhitektonika is especially in details developed by researches S. Vogt and O. Vogt. Miyeloarkhitektonicheski new bark breaks up to six main layers corresponding to cytovery tectonic layers (fig. 4). The layer 1 is called in a miyeloarkhitektonik tangential (lamina tangentialis) since take place in it directed horizontally (parallel to a surface) the tangential fibers which are carrying out intracortical bonds. Mostly it consists of four underlayers, but can consist also of three or two underlayers. The layer 2 is called disfibrozny (lamina disfibrosa) since it is poor in myelin fibers. The layer of 3 (lamina suprastriata) corresponds to a pyramidal layer in a cytovery tectonic picture and, as well as there, mostly is divided into three underlayers. In some fields in an upper underlayer the strip (stria laminae granularis externae) consisting of dense accumulation of horizontal myelin fibers described by V. M. Bekhterev and being an important episeme of this field is allocated. The layer 4 is characterized, as well as the strip of an outside granular plate, dense accumulation of horizontal myelin fibers and is called a strip of an internal granular plate — an outside strip of Bayarzhe (stria laminae granularis internae). The layer 5 consists of two underlayers: the underlayer 5a is designated as lamina intrastriata and the most part contains much less horizontal fibers, than adjoining on it a layer 4 and an underlayer 5b; the underlayer 5b carries the name of a strip of a ganglionic plate — an internal strip of Bayarzhe (stria laminae ganglionaris). The layer 6 consists of four underlayers more or less accurately different from each other. O. Vogt allocates his lower underlayers as a layer 7.

Features in a structure of a tangential layer (four - three - or bizonal type depending on quantity of underlayers) and in a structure and a ratio of strips of Bayarzhe are of great importance for division of bark into fields. The most typically two-way structure — typus bistriatus (both strips are well isolated), but are possible also typus unitostriatus (both strips are merged in a single whole owing to a large amount of fibers in the underlayer which is located between them 5a), typus unistriatus (only the strip of an internal granular plate is isolated, and the strip of a ganglionic plate merges with the subject layer 6) and typus astriatus (in a single whole layers 4, 5 and in owing to density of usually lighter intermediate layers formed by an underlayer 5a and an outside underlayer of a layer 5 are merged).

Along with horizontally located myelin fibers on miyeloarkhitektonichesky drugs in bark also radially located fibers (neurofibrae radiales) which enter bark from the subject white matter act and are located in it lucheobrazno. Especially great value for a miyeloarkhitektonichesky differentiation of bark is related radial fibers to layers of bark. Allocate three main types of these bonds: type first (typus euradiatus) where radial fibers reach a layer «?, corresponds to new bark, except front department of upper limbic bark; the type of second (typus infraradiatus) where radial fibers terminate already on border between both underlayers of a layer

5, occupies the forefront of an upper limbic crinkle and also corresponds to a certain department of new bark; type third (typus supraradiatus) where radial fibers pass in a large number in layers 3 and 2, and from here partially get also into a layer 7, corresponds in general to ancient, old and intermediate bark. The first and second O. Vogt designates types as an isocortex, and the third type — as allokorteks.

Studying of very tectonics of fibers of bark of hemicerebrums of the person gained big development in connection with modification of methods of impregnation in recent years (a method A. P. Avtsyna in modification of laboratory of very tectonics Ying-that a brain) and use of quantification of fibrous structures by means of densitometry [A. Hopf, 1968]. Thanks to it not only the myelin, but also amyelinic fibers which are most powerfully presented in top coats of bark are revealed (i, 2, 3, 4). The data Ying-that a brain (1972) which are not contradicting philosophy of miyeloarkhitektonichesky classification S. Vogt and O. Vogt at the same time showed considerably big variability of distribution of radial and horizontal fibers in various departments of a cerebral cortex of the person.

An angioarchitecture (angioarchitectonica corticis)

Pfeyfer (R. Pfeifer, 1928) showed that both separate layers of bark, and its separate formations differ in features of a structure of a capillary network, and gave the description of an angioarkhitektonichesky structure of occipital area (field 17 and 18), the precentral crinkle, upper parietal segment (lobulus parietalis sup.), parahippocampal crinkle. Angioarkhitektonichesky researches considerably expand knowledge of a structure of bark of big cerebral hemispheres reached cyto - and miyeloarkhitektoniky. See also Brain (blood supply).

The synaptology

the Synaptology did not reach yet that stage of development when on its basis as on the basis of data cyto - and miyeloarkhitektonik, it would be possible to allocate formations of bark of big cerebral hemispheres. However and in this area very important data are obtained. Classical researches of Kakhal (S. Ramon at Cajal, 1909 — 1911), and in domestic literature — S. A. Sukhanov's works are of especially great importance for the doctrine about neural structures (1899). Further researches Laurent de No (R. Lorente de Νό), C. A. Sarkisova, A. D. Zurabashvili, G. I. Polyakova and many others allowed to approach a classification issue of neurons and creation of schematic diagrams of the organization of various neural complexes in cortical and subcrustal formations of a brain.

The considerable quantum leap in development of a synaptology in the last decades is connected using a submicroscopy for studying synapse (see).

Very tectonics of bark of hemicerebrums and questions of localization of functions

Meynert (T. Meynert, 1868) formulated on the basis of the very tectonic researches the doctrine about bark of hemicerebrums as about set of bodies, i.e. educations with various functions, and about very tectonics as about «organology». V. A. Bets specified that division of a brain into areas can be carried correctly out only on the basis of thin studying of a structure of bark. Revealing with immutable evidence that bark of a great brain is differentiated on variously constructed formations, data of very tectonic researches completely disprove ideas of a number of authors of uniformity of its functions in all areas. At the same time the data of very tectonics which are especially given to evolutionary morphology show that all areas of bark, including also the most primitive, are educations functionally - multiple-valued and that there are no such areas of bark which would represent the «centers» providing only one any function (see. Cerebral cortex ). The provision on a localizability of cortical functions from it does not lose the value. If many very tectonic formations also take part in implementation of this or that function, then it does not mean at all that participation it is identical to all formations; it is undoubted that activity of some of them is at the same time dominating, and activity of others is of only more or less secondary importance.

The principle of localization of cortical functions formulated by I. P. Pavlov and A. A. Ukhtomsky assumes dynamic systems which elements keep strict differentiation and play a highly specialized role in uniform activity.

Especially fruitful for the solution of questions of localization of functions (see) there was a complex research (very tectonic and physiological) conducted S. Vogt and O. Vogt on monkeys. On borders of the sites giving various motor reaction on irritation cuts on a live brain for the purpose of clarification of a question of anatomic substrate of these physiological borders were carried out.

The electrophysiologic research of a projective cortical zone of the visual analyzer showed existence of various types of neurons — with simple and difficult receptive fields [R. Jung, 1961; D. H. Hubel and Vizel (T. N. Wiesel), 1963], and the vertical organization of neural ensembles with identical receptive fields allowed authors to put forward the principle of the organization of analizatorny cortical zones in «functional columns». Morphologically this sign was described as the vertical striation which is coming to light in some areas of new bark earlier.

During the studying of the structurally functional organization of bark it must be kept in mind that of both sensomotor, and vegetative components of the complete behavioural act take part in implementation, in addition to bark, subcrustal, trunk and spinal formations of c. N of page which interaction and interference defines adequacy of any adaptive process.

See also Brain , Cerebral cortex , Patoarkhitektonika .

Tables

Table 1


Symbols: to tab. 2, 3, 4 and 5: ↓ - reduction &otnositelnoynbsp; the areas of structure in the ascending number of primacies; ↑— increase in the relative area of structure in the ascending number of primacies.

Table 2


Table 3


Table 4


Table 5


Table 6



Bibliography: Very tectonics of fibers of bark of a great brain of the person, under the editorship of S. A. Sarkisov, M., 1972, bibliogr.; Blinkov S. M. and Glezer I. I. A brain of the person in figures and tables, L., 1964, bibliogr.; L at r and I am A. R. the Highest cortical functions of the person and their disturbance at local damages of a brain, page 37, M., 1969, bibliogr.; Development of a brain of the child, under the editorship of S. A. Sarkisov, L., 1965; Stankievich I. A. About specialization of the course of ontogenesis of a great brain of the person, Usp. sovr. biol., t. 58, century 3, page 409, 1964; Filimonov I. N. Comparative anatomy of a great brain of reptiles, M., 1963, bibliogr.; Shevchenko Yu. G. Evolution of a cerebral cortex of primacies and person, M., 1971, bibliogr.; Yu N of of River. Integration in neurons of visual bark and its value for visual information, in book: The theory of communication in sensorn. sist., the lane with English, under the editorship of G. D. Smirnov, page 375, M., 1964, bibliogr.; Contemporary research methods in neuroanatomy, ed. by W. J. H. Nauta a. S. Lake of E. Ebbesson, N. Y. a. o., 1970, bibliogr.; Η about p f A. Registration of the myelo-architecture of the human frontal lobe with an extinction method, J. Himforsch., Bd 10, S. 259, 1968, Bibliogr.; H ub e 1 D. H. a. W i e s e 1 T. N. Receptive fields, binocular interaction and functional architecture in the cat’s visual cortex, J. Physiol. (Lond.), v. 160, p. 106, 1962, bibliogr.; Pfeifer R. A. Die Angioarchitek-tonik der Grosshirnrinde, V., 1928, Bibliogr.

And. H. Filimonov, V. S. Kesarev.

Яндекс.Метрика