LIMBIC SYSTEM

From Big Medical Encyclopedia

LIMBIC SYSTEM (synonym: visceral brain, limbic share, limbic complex, timentsefalon) — a complex of structures of the final, intermediate and average departments of a brain making substrate for manifestation of the most general conditions of an organism (a dream, wakefulness, emotions, motivations etc.). The term «limbic system» is entered P. Mac-Lane in 1952.

There is no consensus about exact structure of the structures which are a part of Hp. Most of researchers, in particular, consider hypothalamus (see) as independent education, allocating it from Hp. However such allocation is conditional since on a hypothalamus there is a convergence of the influences proceeding from the structures participating in regulation of various vegetative functions and formation of emotionally charged behavioural reactions. Communication of functions of Hp with activity of internals gave the grounds a nek-eye to authors to designate all this system of structures as «a visceral brain», however this term only partially reflects funkts, value of system. Therefore most of researchers apply the term «limbic system», emphasizing with that that all structures of this complex phylogenetic, embryological and are morphologically connected with a big limbic share of Brock.

The main part of Hp is made by the structures relating to ancient, old and new bark, located preferential on a medial surface of cerebral hemispheres and numerous subcrustal educations, is close with them connected.

At the initial stage of development of vertebrate animals of structure of Hp provided all major reactions of an organism (food, approximate, defensive, sexual). These reactions formed on the basis of the first distantny feeling — sense of smell. Therefore sense of smell (see) acted as the organizer of a set of complete functions of an organism, having combined and morfol, their basis — structure of final, intermediate and average departments brain (see).

Fig. 1. Morfofunktsionalny characteristic of limbic system: and — the scheme of an arrangement of structures of limbic system (in the center Peyps's circle): 1 — a zone crinkle, 2 — a precuneus, 3 — a parahippocampal crinkle (actually limbic system is shaded); shooters showed functional interrelations of structures; — the scheme of interaction of structures of a circle of Peyps: 1 — amigdaloidny area, 2 — olfactory system, 3 — a partition, 4 — the arch, 5 — a zone crinkle, 6 — a hippocampus, 7 — a front kernel of a thalamus, 8 — a hypothalamus, 9 — entorinalny bark; black shooters designated morphological bonds of a circle of Peyps, light — the bonds which are not entering it.

Hp — a difficult interlacing of the ascending and descending ways forming a set of the closed concentric circles of different diameter within this system. From them it is possible to allocate the following circles: amigdaloidny area — a final strip — a hypothalamus — amigdaloidny area; a hippocampus — the arch — septal area — mamillary (mastoidal, T.) bodies — a mastoidal and thalamic bunch (Vick-d'azira) — a thalamus — a zone crinkle — a zone bunch — a hippocampus (Peyps's circle, fig. 1).

The ascending ways of Hp anatomically are studied insufficiently. It is known that they along with classical touch pathways include as well diffusion, going not as a part of a medial loop. The descending ways of Hp connecting it with a hypothalamus reticular formation (see) a mesencephalon and other structures of a brainstem, take place in the basic as a part of a medial bunch of a neoncephalon, final (terminal, t.) strip and arch. The fibers going from hippocampus (see), hl terminate. obr. in the field of a lateral part of a hypothalamus, in a funnel, a preoptichesky zone and mamillary bodies.

Morphology

the olfactory bulbs, olfactory legs passing into the respective highways, olfactory hillocks, the front made a hole substance, the diagonal bunch of Brock limiting behind the front made a hole substance, and two olfactory crinkles — lateral and medial with the corresponding strips enter Hp. All these structures are combined by the general name «olfactory share».

On the medial surface of a brain the forefront of a brainstem and mezhpolusharny commissures surrounded with a big arc-shaped crinkle which dorsal half occupies zone, and ventral — parahippocampal crinkles belong to Hp. Behind zone and parahippocampal crinkles form retrosplenialny area, or an isthmus (isthmus). Ahead between the anteroinferior ends of these crinkles bark of a back orbital surface of a frontal lobe, the forefront of an island and pole of a temporal share is located. The parahippocampal crinkle should be distinguished from the hippocampal formation formed by a body of a hippocampus, a gear crinkle, or a gear fascia, the okolokallozalny rest of old bark and, according to nek-ry authors, subikulumy and presubikulumy (i.e. the basis and the prebasis of a hippocampus).

The parahippocampal crinkle is subdivided into the following three parts: 1. Pear-shaped area (area piriformis), edges at makrosmatik forms a pear-shaped share (lobus piriformis) occupying the greatest part of a hook (uncus). It is subdivided, in turn, into periamigdaloidny and prepiriformny areas: the first covers the nuclear mass of amigdaloidny area and at the same time is very badly separated from it, the second merges ahead with a lateral olfactory crinkle. 2. Entorinalny area (area entorhinalis) occupying a middle part of a crinkle from below and behind from a hook. 3. The Subikulyarny and presubikulyarny areas located between entorialny bark, a hippocampus and retrosplenialny area and occupying a medial surface of a crinkle.

Subcallosal (paraterminal, t.) the crinkle together with a rudimentary front hippocampus, septal kernels and gray prekomissuralny educations sometimes is called septal area, and also pre-or parakomissuralny area.

From formations of new bark nek-ry researchers carry its temporal and frontal departments and an intermediate (frontotemporal) zone to Hp. This zone lies between prepiriformny and periamigdaloidny bark, on the one hand, and orbito-frontal and temporal and polar — with another. Sometimes it is called orbito-insulovisochny bark.

Phylogenesis

Fig. 2. Diagrammatic representation of a ratio of bark of limbic system and new bark of a rat (a), cat (b), monkey (v) and person (): 1 — a subcallosal crinkle; 2 — a zone crinkle; 3 — retrosplenialny area; 4 — entorinalny bark; 5 — a parahippocampal crinkle; 6 — a hook; by white color new bark, black — bark of limbic system is designated.

All formations of a brain making Hp belong to most phylogenetic to its ancient areas and therefore they can be found in all vertebral (fig. 2).

Evolution of limbic structures among vertebrata is closely connected with evolution of the olfactory analyzer and those formations of a brain, to-rye receive impulses from an olfactory bulb. The lowest vertebrata (Cyclostoma, fishes, amphibians and reptiles) have the first acceptors of such olfactory impulsation septal and amigdaloidny areas, a hypothalamus, and also old, ancient and interstitial areas of bark. Already at the earliest stages of evolution these structures were closely connected with kernels of the lower brainstem and performed the most important integrative functions, to-rye provided to an organism adequate adaptation to conditions of the environment.

In the course of evolution due to extremely intensive growth of new bark, a neostriatum and specific kernels of a thalamus relative (but not absolute) development of limbic structures decreased a little, however did not stop. They only underwent nek-ry morfol, and topographical changes. So, e.g., at the lowest vertebrata the very striatum, or an almond, holds almost median position of an end brain, at marsupials is located at the bottom of a temporal horn of a side ventricle, and at the majority of mammals is displaced by the temporal end of a horn of a side ventricle, getting a form of almonds in this connection received the name of an almond. This structure occupies area of a pole of a temporal share the person.

The septal area at all animals, except primacies, is the extensive part of an end brain making a medial surface of hemispheres. At the person all nuclear mass of septal area is displaced in the ventral direction and therefore the verkhnemedialny wall of a side ventricle is formed by not ganglionic elements of a brain, but a peculiar film — a transparent partition (septum pellucidum).

Ancient cortical formations in the course of evolution underwent so serious changes that turned from superficial structures like a raincoat into separate discrete formations of the most bizzare shape. So, old bark got a form of a horn and began to be called an ammonovy horn, ancient and interstitial areas of bark turned into an olfactory hillock, an isthmus, bark of a pear-shaped crinkle.

During evolution limbic structures entered close connection with younger formations of a brain, providing to high-organized animals thinner adaptation to the becoming complicated and constantly changing living conditions.

The cytovery tectonics of bark of limbic system

Ancient bark (paleocortex), according to I. N. Filimonov, is characterized by primitively constructed cortical plate, edges indistinctly separates from the subject subcortical cellular accumulations. The pear-shaped area, an olfactory hillock, diagonal area, a basal part of a partition are its part. Over a molecular layer of ancient bark the afferent fibers which in other cortical areas are taking place in white matter under bark are located. Therefore bark is also not separated so accurately from a subcortex. Under a fiber layer it is located molecular, then the layer of colossal polymorphic cells, is even deeper — a layer of pyramidal cells with kisteobrazny dendrites at the basis of a cell (buketny cells) and, at last, a deep layer of polymorphic cells.

Old bark (very cortex) has the arc-shaped form. Surrounding a corpus collosum and a fimbria of a hippocampus, it adjoins in front the back end with periamigdaloidny, and to lobbies — with diagonal areas of ancient bark. Carry a hippocampal formation and subikulyarny area to old bark. Old bark differs from ancient in full separation of a cortical plate from the subject educations, and from new — simpler structure and lack of characteristic division into layers.

Interstitial bark call the areas of bark separating new bark from old (periarkhikortikalny) and ancient (peripaleokortikalny).

The cortical plate of the periarkhikortikalny zone separating throughout old bark from new is divided into three main layers: outside, average and internal. Presubikulyarny, entorinalny and peritektalny areas belong to interstitial bark of this type. The last represents a part of a zone crinkle and directly adjoins to a nadmozolisty rudiment of a hippocampus.

Peripaleokortikalny, or transitional insular, the zone surrounds ancient bark, separating it from new bark, and is closed behind with a periarkhikortikalny zone. It consists of a number of the fields which are carrying out consecutive, but discontinuous transition from ancient bark to new and occupying the naruzhnonizhny surface of bark of an island.

In literature it is often possible to meet also other classification of cortical structures of Hp — from the cytovery tectonic point of view. So, Vogt (S. of Vogt) both O. Vogt (1919) arkhi-and a paleocortex together call allokorteksy or heterogenous bark. To. Ford May (1909), Rose (M. of Rose, 1927) and Rose (J. E. Rose, 1942) bark limbic, retrosplenialny and the nek-ry other areas (e.g., an island) forming intermediate bark between a neocortex and allokorteksy call a mesocortex. I. N. Filimonov (1947) calls intermediate bark a paraallocortex (juxtallocortex). Pribram, Kruger (K. N. of Pribram, L. Kruger, 1954), Kaad (V. of R. Kaada, 1951) consider a mesocortex only as a part of a paraallocortex.

Subcrustal structures. Basal kernels, nonspecific kernels of a thalamus, a hypothalamus, a lead and, according to nek-ry authors, a reticular formation of a mesencephalon belong to subcrustal formations of Hp.

Basal kernels (see) — the most ancient formations of Hp presented by a paleostriatum, a very striatum and a neostriatum. At the person the paleostriatum includes a pale sphere (globus pallidus, or pallidum), a very striatum — an almond, both a neostriatum — a shell and a kernel having a tail (putamen, nucleus caudatus). Sometimes two last educations are called a striatum or a neostriatal body.

The special attention of physiologists, psychologists and clinical physicians attracts amigdaloidny area (see). At mammals the amigdaloidny area is formed by the mass of the gray matter lying in the depth of a temporal share ventrally to a lenticular kernel, being as if its continuation. Interfering on a cortical surface, she participates in formation of bark of a hook at the person or the forefront of a pear-shaped share at the lowest mammals. Like other basal kernels, amigdaloidny area — phylogenetic heterogeneous education. All its cellular weight is subdivided into several kernels, grouped in two nuclear complexes: younger basolateral complex consisting from lateral, basal and additional basal kernels and more ancient kortikomedialny complex consisting of the central, medial and cortical kernels, a kernel of an olfactory path and kortiko-amigdaloidny intermediate area.

Many authors carry the most ancient nonspecific kernels to Hp thalamus (see), closely connected with a hypothalamus, an almond, a striate body and a partition.

At the person the front kernels which are subdivided into three subgroups concern to them: anteroinferior, anterosuperior and anteromedial. Sometimes allocate a paratenialny kernel, but also, kernels of the centerline — okolozheludochkovy, rhomboid, central medial and nucleus reuniens. Kernels of medial group are located medially from an internal brain plate of a thalamus or even in it. The arrangement defines their name — intralaminarny kernels. The most considerable of them are the following kernels: upper medial, subthalamic kernel of Lyuis, the lower medial, parafascicular, paracentral and lateral central.

Zager (O. of Sager, 1969) all kernels hypothalamus (see) classified as follows: 1) preoptichesky area (paraventrikulyarny, medial and lateral preoptichesky kernels); 2) front group of kernels (supraopticheeky, suprakhiazmatichesky, diffusion supraoptic and paraventrikulyarny); 3) average group of kernels (nizhnemedialny and verkhnemedialny); 4) outside group of kernels (lateral hypothalamic kernel and kernel of a gray hillock); 5) back group of kernels (zadnegipotalamichesky, perifornikatny, premamillyarny, medial mamillary, supramamillyarny and lateral mamillary).

Also the kernels of a lead of an epithalamus (habenula) closely adjacent to a thalamus though functionally it is not enough with it connected belong to subcrustal formations of Hp. At the highest animals they are located on the dorsal surface of a thalamus and arise in connection with development of a parietal photoreceptor — so-called parietal, or pineal, body. Being located in close proximity to parietal body, these kernels send impulses to back department of the basis of a mesencephalon and thus provide funkts, communication of a neoncephalon with back departments of a mesencephalon.

Intermediate (between cortical and subcrustal) education is septal area (see). It is located in triangular space between the arch and a corpus collosum. The nuclear part of the septal area belongs to subcrustal educations. Allocate the following kernels: kernels of a final strip and front commissure, septal and basal kernels of a diagonal bunch, dorsal, medial, lateral, fimbrialny and triangular.

Fig. 3. The diagrammatic representation of the main structures of limbic system of the person and bonds between them (are designated by shooters and dashed lines): 1 — cells of an olfactory epithelium; 2 — an olfactory bulb; 3 — an olfactory path; 4 — front commissure: 5 — a corpus collosum; 6 — a zone crinkle; 7 — front kernels of a thalamus; 8 — a final strip; 9 — the arch; 10 — a brain strip; 11 — a kernel of a lead (a habenulyarny complex of kernels); 12 — an intercrural kernel; 13 — a mamillary body; 14 — amigdaloidny area.

Morphological bonds (fig. 3). The main ascending ways of Hp (olfactory) begin from sensory voloskovy cells of an olfactory epithelium (see. Olfactory analyzer ). The central shoots of these cells form an olfactory nerve. Fibers of an olfactory nerve are included into an olfactory bulb. The olfactory bulb, in addition to signals from the first sensitive neuron, receives impulses on centrifuge ways from basal structures of Hp and a contralateral bulb (on the fibers passing in a front circle of front brain commissure — commissura alba ant.).

At all vertebrate animals impulses from olfactory bulbs go on two highways — a lateral olfactory path and more diffusion projective system forming average and medial olfactory paths or join a rostral part of front commissure of a brain. These ways — shoots of mitral and puchkovy cells of an olfactory bulb.

The lateral olfactory path passes near an olfactory hillock and extends to area of piriformny bark and an almond where its fibers fanlikely branch and disappear. A part of these fibers terminates in dorsal and external parts of a front olfactory kernel, a small number — in other part of this row. Other collaterals terminate in an olfactory hillock and temporal, prepiriformny and periamigdaloidny bark, coming into aksodendritny contacts with pyramidal cells in a plexiform layer. Nek-ry fibers pass to amigdaloidny area where terminate about cellular bodies in a medial kernel and a kernel of a lateral olfactory path and on dendrites of some pyramidal cells in a cortical amigdaloidny kernel.

Hippocampus (see) receives fibers from a contralateral hippocampus, septal area, especially its medial kernel, a presubikulum, entorinalny area and probably a zone crinkle. The main descending system of a hippocampus — the arch (fornix) — bears also many afferent fibers from the listed formations of a brain. In a hippocampus fibers begin, to-rye pass through a leaf of a hippocampus (alveus hippocampi) and create a yarn — a small fringe of a hippocampus (fimbria hippocampi). The small fringe increases in volume of a pas to a measure of that as approaches the roller of a corpus collosum, under the Crimea it together with the analog of the opposite side also forms the arch. Ahead the arch proceeds in the form of two arc-shaped columns of the arch (columnae fornicis) to mastoidal bodies of a hypothalamus.

The ground mass of fibers of a fimbria of a hippocampus is divided into two bunches. The first bunch — the postkomissuralny arch — compact, deeply plunges behind front commissure of a brain into a hypothalamus, passes through it and the hl approaches. obr. to a mastoidal body. A large number of these fibers — descending. They terminate in a front kernel, and also in rostral intralaminarny and medial areas of a thalamus. A few other fibers terminate in medial and periventrikulyarny areas of a hypothalamus. The second bunch — the prekomissuralny arch — the descending and ascending group of the fibers which are getting into a partition and passing ahead of front commissure of a brain. Many of these fibers pass further and join a medial bunch of a neoncephalon together with which they go to lateral department of preoptichesky area and to a kernel of a diagonal bunch of Brock. Some fibers of the arch go as a part of a diagonal bunch up to amigdaloidny area though any of them does not enter it. Direct ways from a hippocampus to amigdaloidny area, apparently, do not exist. However it is possible to assume between them existence of indirect bonds with switching in a kernel of a diagonal bunch and in preoptichesky area.

Commissure of a hippocampus includes bilateral ties of two next ammonovy horns. Believe that its rostral part also contains the fibers reaching a contralateral partition.

Connection of a hippocampus with new bark is established through a temporal ammonovy paths. The influence on a hippocampus and a zone crinkle extends, establishing aksodendritny connection with pyramidal and its granular cells. It is possible that carriers of these influences are the groups of fibers passing through a corpus collosum and a zone bunch.

The hippocampus receives many fibers from a presubikulum, for to-rogo they are the only efferent channels. Afferent ways of a presubikulum go from a zone crinkle from the subcallosal strips beginning around a partition, and also partly from nonspecific laminar kernels of a thalamus of an intr.

As it was already noted, nek-ry fibers of the postkomissuralny arch, without having reached mastoidal bodies, turn to front kernels of a thalamus and there terminate. These are direct gipiokampo-thalamic projections. The fibers rising to the same kernels from mamillary bodies as a part of a mamillary and thalamic bunch are more noticeable. In thalamic kernels there is a switching of these fibers to projections to a zone crinkle. The anteromedial kernel is projected on an agranular rostral part of a zone crinkle; an anteroinferior kernel — on its granular tail, anterosuperior — on retrosplenialny area. Thus, around «gate» of a hemisphere the circle consisting of a hippocampus, the arch, a hypothalamus, a thalamus, a zone crinkle, a belt of a brain and again a hippocampus becomes isolated. This circle of Peyps (J. W. Papez, 1937) considered as nervous substrate of emotions (Peyps's circle).

Many formations of Hp send projective fibers to a transparent partition. This structure, being one of the main acceptors of secondary olfactory ways (from an olfactory bulb) and receiving fibers of the third order from an olfactory hillock, amigdaloidny area and a hippocampus, is the main transfer station of signals to lower parts of a brain, first of all to a subthalamus and an epithalamus — especially to kernels of a habenulyarny complex. The transparent partition connects by a lead of an epithalamus very difficult conduction formation of stria medullaris consisting of the descending fibers of septal and preoptichesky areas, a hypothalamus, pear-shaped share, subcallosal crinkle, nek-ry kernels of amigdaloidny area, and probably collaterals of a final strip and the arch. Fibers of this strip go to medial nucleus habenulae of an epithalamus. Nek-rye from them cross in commissure of a lead.

Kernels of a habenulyarny complex — the last transfer points on the way from Hp to a lower part of a brainstem. From a lead to an intercrural kernel there is a povodkovo-nozhkovy bunch (Meynert's bunch). To a tire of a mesencephalon there are more direct descending ways — mamillary pokryshechny a bunch. In the beginning this bunch follows together with a mamillary and thalamic bunch. Then the lateral branch which is partially coming to an end in a subthalamic kernel and reaching a tire of a mesencephalon departs from this general way.

The area of a lateral hypothalamus is connected with a tire through a medial bunch of a neoncephalon.

The medial bunch of a neoncephalon connects ventromedialny formations of an end brain with lateral areas intermediate and nek-ry structures of an average of departments of a brain. This education consists of fibers of various nature and orientation, to-rye pases all extent join it. At mammals the medial bunch of a neoncephalon receives fibers from a front olfactory kernel (or even from an olfactory bulb), an olfactory hillock, piriformny bark and an amygdaloid nucleus, a head of a kernel having a tail, back orbital bark and stretches to a reticular formation of a mesencephalon. Nek-ry authors consider that it terminates in front horns of cervical segments of a spinal cord. On the other hand, this bunch accepts the fibers from kernels of a tire of a mesencephalon and the central gray matter reaching partially a hypothalamus, septal area, amigdaloidny area, an olfactory hillock, a front olfactory kernel and an olfactory bulb. A kernel (bed) of a medial bunch of a neoncephalon is a lateral part of a hypothalamus where the fibers of the arch connecting it with a lead and a thalamus join. Morphological bonds of amigdaloidny area — see. area Amigdaloidnaya .

Neurochemistry

Fig. 4. The diagrammatic representation of a projection of dofaminergichesky neural system (structures in which bombways of dofaminergichesky neurons terminate are shaded): 1 — a kernel having a tail; 2 — n. acumbens; 3 — an olfactory hillock: 4 — the central kernel of amigdaloidny area; 5 — a hypothalamus; 6 — a medial eminence of a hypothalamus; 7 — black substance and kernels of a tire where bodies of dofaminergichesky neurons lie; 8 — a cerebellum; bodies of neurons are designated by black circles.
Fig. 5. The diagrammatic representation of a projection of noradrenergichesky neural system (structures in which bombways of noradrenergichesky neurons terminate are shaded): 1 — an olfactory bulb; 2 — a zone crinkle; 3 — septal area; 4 — a hippocampus; 5 — a final strip; — a hypothalamus; 7 — ventral and 8 — dorsal bunches of a noradrenergichesky way; 9 — kernels of a myelencephalon; 10 — a livor; 11 — a cerebellum; bodies of neurons are designated by black circles.

On the basis of the data obtained in the last decades with the help gistokhy, methods of a research, generally a method of fluorescent microscopy, it was shown that practically all structures of Hp accept bombways of the neurons cosecreting various biogenic amines (so-called monoaminergichesky neurons). Bodies of these neurons lie in the area of the lower brainstem. According to the cosecreted biogenic amine allocate three types of monoaminergichesky neyronalny systems — dofaminergichesky (fig. 4), noradrenergichesky (fig. 5) and serotonergic. In the first three ways are allocated.

1. Nigroneo-striatny begins in black substance and terminates on cells of a kernel having a tail and shells. Each neuron of this way has a set of bombways (to 500 000) with a total length of shoots up to 65 cm that gives the chance instantly to influence a large number of cells of a neostriatum. 2. Mesolimbic begins in ventral area of a tire of a mesencephalon and terminates on cells of an olfactory hillock, septal and amigdaloidny areas. 3. Tubero-infundibulyarny originates from the forefront of an arkuatny kernel of a hypothalamus and terminates on cells of eminentia mediana. All these ways mononeyronalny also do not contain synoptic switchings.

The ascending projections of noradrenergichesky system are presented in two ways: dorsal and ventral. Dorsal begins from a livor, and ventral — from a lateral reticular kernel and a krasnoyaderno-spinal way. They stretch forward and terminate on cells of a hypothalamus, preoptichesky area, septal and amigdaloidny areas, an olfactory hillock, an olfactory bulb, a hippocampus and new bark.

The ascending projections of serotonergic system begin from kernels of a seam of a mesencephalon and a reticular formation of a tire. They stretch together with fibers of a medial bunch of a neoncephalon forward, giving many collaterals to the area of a tire on border of intermediate and average departments of a brain.

Shat and Lyois (G. The page of D. Shute, P. R. Lewis, 1967) showed that in Hp there is a large amount of the substances connected with exchange of acetylcholine; they tracked accurate cholinergic ways from reticular and pokryshkovy kernels of a brainstem to many formations of a neoncephalon, and first of all to limbic — so-called dorsal and ventral tegmental ways, to-rye directly or with one-two synoptic switchings reach many talamo-hypothalamic kernels, structures of a striate body, amigdaloidny and septal areas, an olfactory formation, a hippocampus and new bark.

In Hp, especially in olfactory structures, it is revealed a lot of glutaminic, asparaginic and piperidic to - t what can demonstrate mediator function of these substances.

Hp contains a significant amount of biologically active agents relating to group of enkephalins and endorphines. Most of all they contain in a striate body, an amygdaloid nucleus, a lead, a hippocampus, a hypothalamus, a thalamus, an intercrural kernel and other structures. Only in these structures receptors are found, to-rye perceive effect of substances of this group — so-called opiate receptors [Snider (S. And. Snyder), 1977].

In 1976 Veyndlom et al. (And. Weindl) was revealed that, in addition to a hypothalamus, septal and amigdaloidny areas, and partly and a thalamus contain the neurons capable to cosecrete neuropeptids like vasopressin, etc.

Physiology

Combining formations of final, intermediate and average departments of a brain, Hp provides formation of the most general functions of an organism which are implemented through the whole range separate or the interfaced private reactions. In structures of Hp there is an interaction exteroceptive (acoustical, visual, olfactory, etc.) and interoceptive influences. Even at the most primitive impact practically on all structures of Hp (mechanical, chemical, electric) it is possible to find a number of the isolated simple or fragmentary answers differing on degree of manifestation and stage of latency depending on what structure is exposed to irritation. Such vegetative reactions as a sialosis, a piloerektion, defecation, etc., changes in work respiratory, cardiovascular and limf, systems, change of a pupillary test, thermal control etc. are often observed. Duration of these reactions happens sometimes very considerable that demonstrates inclusion in work and separate endocrine devices. Often such vegetative reactions are observed together with coordinate motor manifestations (e.g., chewing, deglutitory and other movements).

Along with vegetative reactions of Hp defines also vestibulosomatichesky functions, and also such somatic reactions as poznotonichesky and voice. Apparently, Hp should be considered as the center of integration of vegetative and somatic components of reactions of hierarchically more high level — emotional and motivational states, a dream, approximate and research activity etc. These composite reactions are shown at animals or the person at irritation of quite certain structures of Hp. It is shown that the irritation or destruction of an almond, partition, frontotemporal bark, a hippocampus and other departments of limbic system can lead to strengthening or, on the contrary, weakening of pishchedobyvatelny, defensive and sexual reactions. Especially visually in this respect destruction of temporal, orbital and insulyarny bark, an almond and the part of a zone crinkle adjoining them, defiant emergence of a so-called syndrome of Klyuver — Byyusi, at Krom is broken ability of animals to estimate both the internal state, and usefulness or harm of external irritants. Animals after such operation become manual; continuously inspecting surrounding objects, they without analysis are enough everything that comes across, lose fear even before fire and, even burning, continue to touch it (there is so-called visual agnosia). Quite often they become to expression hyper sexual, showing sexual reactions even concerning animals of other look. Also their relation to food changes.

Fig. 6. The scheme of the ascending activating influences of the hypothalamic centers caused by «internal» requirements of an organism (K. V. Sudakov, 1971): and — at a lack of blood of certain substances of a hypothalamus there is an excitement extending on other limbic structures and also through kernels of a thalamus and a reticular formation to bark of big hemispheres (it is designated by black shooters); — in the absence of special irritants from internal environment the ascending activating influence on bark of big hemispheres is not noted: dashed lines do not reach area of a cerebral cortex.

The richness of interrelations in Hp defines also other party of emotional activity — a possibility of considerable strengthening of emotion, duration of its keeping and quite often its transition to a congestive patol, a state. J. W. Papez, e.g., considers that the emotional state is result of circulation of vozbuzhdeniye on structures of Hp from a hippocampus through mamillary bodies (see) and front kernels of a thalamus to a zone crinkle, and the last, in his opinion, is also truly receptive zone of the experienced emotion. However the emotional state which is shown not only is subjective, but also promoting this or that purposeful activity, i.e. reflecting this or that motivation of an animal, arises, apparently, only in that case when excitement from limbic structures extends to new bark, and first of all in its frontal departments (fig. 6). Without participation of new bark emotion turns out defective; it loses the biol, the sense also acts as false.

The motivational conditions of animals arising in response to electric irritation of a hypothalamus and closely related limbic educations behavioural can be shown in all their natural complexity, i.e. in the form of rage and organized reactions of attack on other animal or, on the contrary, in the form of reactions of defense and avoiding of an unpleasant irritant or running away from the attacking animal. Participation of Hp in the organization of pishchedobyvatelny behavior is especially noticeable. So, bilateral removal of an almond leads or to long failure of animals from food, or to a hyperphagia. As showed To. V. Sudakov (1971), Noda (To. Noda) with sotr. (1976), Paksinos (G. Paxinos, 1978), changes of pishchedobyvatelny behavior and reaction of a satisfying of thirst are observed also in case of irritation of a pla of destruction of a transparent partition, piriformny bark and nek-ry mezentsefalichesky kernels.

Removal of an almond and pear-shaped bark leads to gradual development of the expressed hyper sexual behavior, a cut it is possible to weaken or remove destruction of a nizhnemedialny kernel of a hypothalamus or septal area.

Impacts on Hp can lead to the motivational changes of higher order which are shown at the level of community. The most defiantly emotional and motivational conditions of animals are shown in case of their reactions of self-stimulation or avoiding of an adverse irritant when various formations of Hp are affected.

Formation of the behavioural act on the basis of any motivations (see) begins with approximate and research reaction (see). The last as show experimental data, is also implemented with obligatory participation of Hp. It is established that action of the indifferent irritants causing behavioural reaction of a nastorazhivaniye is followed by characteristic electrographic changes in structures of Hp. While in bark of big hemispheres at the same time desynchronization of electric activity, in nek-ry structures of Hp, napr, in amigdaloidny area, a hippocampus and pear-shaped bark is registered, there are other changes of electric activity. Against the background of rather reduced activity paroxysmal flashes of high-frequency fluctuations are found; in a hippocampus the slow regular rhythm with a frequency of 4 — 6 of 1 sec. is registered. Such reaction, typical for a hippocampus, arises not only at touch irritations, but also at the straight line of an electric reticular formation of stimulations and any limbic structure leading to emergence of behavioural reaction of a nastorazhivaniye or concern.

Numerous experiments show that weak irritations of limbic structures in the absence of specific emotional reaction always cause a nastorazhivaniye or approximate and research reaction of an animal. Identification by an animal in the environment of signals, significant for this situation, and their storing is closely connected with oriyentirovochnoissledovatelsky reaction. In implementation of these mechanisms of orientation, training and storing the big part is assigned to a hippocampus and amigdaloidny area. Destruction of a hippocampus sharply breaks short-term memory (see). During irritation of a hippocampus and some time after it animals lose ability to answer conditioned excitators.

A wedge, observations show that bilateral removal of a medial surface of temporal shares also causes heavy dysmnesias. At patients retrograde amnesia is observed, they completely forget the events preceding operation. Besides, ability of storing worsens. The patient cannot remember the name-tsy, in a cut is. Sharply the short-term memory suffers: patients lose thread of a conversation, are not capable to monitor the account of sports etc. At animals after similar operation earlier acquired skills are broken, ability to development new, especially difficult worsens.

According to O. S. Vinogradova (1975), the main function of a hippocampus is registration of information, and according to M. L. Pigareva (1978) — ensuring reactions to signals with small probability of a reinforcement in cases when there is a deficit of pragmatical information, i.e. emotional pressure.

Hp is closely connected with mechanisms dream (see). R. Hernandez-Peon with sotr. showed that at injections of small doses of acetylcholine or antikholinesterazny substances the dream develops in various departments of Hp at animals. The following departments of Hp are especially effective in this respect: medial preoptichesky area, medial bunch of a neoncephalon, intercrural kernels, Bekhterev's kernels and medial part of a tire of the bridge. These structures make so-called gipnogenny limbiko-srednemozgovy a circle. Excitement of structures of this circle makes funkts, blockade of the ascending activating influences of a reticular formation of a mesencephalon on bark of big hemispheres, to-rye define a condition of wakefulness. At the same time it is shown that the dream can arise at application of acetylcholine" and antikholinesterazny substances and on overlying formations of Hp: the prepiriformny and periamigdaloidny areas, an olfactory hillock, a striate body and cortical areas of Hp located on front and medial surfaces of parencephalons. The same effect can be gained at irritation of bark of big hemispheres, especially its front departments.

It is characteristic that destruction of a medial bunch of a neoncephalon in preoptichesky area interferes with development of the dream caused by chemical irritation of the above-located departments of Hp and bark of big hemispheres.

Nek-ry authors [P. Winter et al., 1966; Robinson (V. W. Robinson), 1967; J. D. Delius, 1971] consider that in Hp there are so-called centers of communications of animals (their voice manifestations) which are accurately correlated with their behavior in relation to the relatives. These centers are formed by structures of amigdaloidny, septal and preoptichesky areas, a hypothalamus, olfactory hillock, nek-ry kernels of a thalamus and tire. Robinson (1976) suggested that the person has two word centers. The first, phylogenetic older, is located in Hp; it is closely connected with motivational and emotional factors and provides low-information signals. This center is controlled by the second — the highest center located in new bark and connected with the dominating hemisphere.

Participation of Hp in formation of difficult integrative functions of an organism is confirmed by data of inspection of mentally sick. So, e.g., senile psychoses are followed by accurate degenerative changes in septal and amigdaloidny areas, a hippocampus, the arch, medial departments of a thalamus, entorinalny, temporal and frontal areas of bark. Besides, at patients with schizophrenia find a large amount of dopamine, noradrenaline and serotonin, i.e. biogenic amines in structures of Hp, disturbance of normal metabolism to-rykh is connected with development of a number of mental diseases, including and by schizophrenia.

Participation of Hp in development is especially noticeable epilepsies (see) and various epileptoidny states. The patients suffering psychomotor epilepsisy, as a rule, have organic damages to the areas occupying limbic structures. It is first of all an orbital part of frontal and temporal bark, a parahippocampal crinkle, especially in the field of a hook, a hippocampus and a gear crinkle, and also an amygdaloid nuclear complex.

Described above a wedge, symptoms usually are followed by an accurate electrographic indicator — in the relevant departments of a brain electric convulsive discharges are registered. Most clearly such activity is registered in a hippocampus though it is shown also in other structures, napr, in an almond and a partition. Existence in them of diffusion textures of nervous shoots, multiple chains of a feed-back creates conditions for a multiplication, deduction and prolongation of activity. From here and extremely low threshold of emergence of so-called postcategories, inherent for structures of Hp, to-rye can proceed after the termination of electric or chemical irritation for a long time.

The lowest threshold for the electric postcategory is found in a hippocampus, an almond and piriformny bark. Idiosyncrasy of these postcategories is their ability to extend from the place of irritation on other structures of Hp

Klin, and experimental data show that in the period of convulsive categories in Hp processes of memory are broken. At patients with temporal and diencephalic defeats full or partial amnesia or, on the contrary, violent flashes of paroxysms of feeling already seen, slyshanny, endured are observed.

Thus, holding median position in limits of c. and. page, the limbic system is capable «to join» quickly practically in all functions of an organism directed to its active adaptation (according to cash motivation) to conditions of the environment. Hp receives afferent sending of excitement from formations of the lower trunk, to-rye in each case can be very specific, from rostral (olfactory) structures of a brain and from new bark. These excitement on system of an interconnection quickly reach all necessary areas of Hp and instantly (through fibers of a medial bunch of a neoncephalon or direct neostriatno-tegmental ways) activate (or brake) executive (motor and vegetative) the centers of the lower trunk and a spinal cord. It reaches formation «specialized» for these specific conditions funkts, system from an accurate morfol, and neurochemical, very tectonics, a cut comes to the end with achievement with an organism of necessary useful result (see. Functional systems ).



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E. M. Bogomolova.

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