The Central mechanism of emotions

Emotions are formed on the basis of physiological processes in the brain and in the organism as a whole. Numerous clinical and experimental observations show that the most clear violation of the emotional sphere can be observed with the defeat of subcortical structures of the brain. Particularly important in this respect, the thalamus and hypothalamus.
Experiments using chronically implanted in subcortical structures of the electrodes [Hess (W. C. Hess) and others] have shown that the irritation of different parts of the thalamus and hypothalamus can cause all forms of emotional reactions.
However, subcortical the concept of emotions was not universal. Even Goltz (F. Goltz, 1892), removing the bark of the big hemispheres, reached the changes emotional reactivity in the animals, which in response to any external irritation caused the reaction of rage. This reaction in the absence of objective criteria, which characterizes subjective condition of the animals, cannon (W. Cannon) called the reaction false (imaginary) rage. Reaction false rage in the most intelligible form was revealed when deleting almond-shaped complex, hippocampus and pear share. Artificial irritation these formations significantly affects the expression of various other forms of emotional reactions, either enhancing or suppressing them.
Clear signs of false rage observed damaged ventromedial nuclei of the hypothalamus, pathological changes in these departments CNS Alpers (C. J. Alpers) described a patient who has experienced a fit of excitement bordering on anger; after his death he had found the most damage to the medial nucleus of the hypothalamus. Various manifestations of wrath are observed at the irritation of the medial forebrain bundle in the lateral part of the hypothalamus, the irritation of the arch in the place where he is included in the lateral hypothalamus. In contrast, the stimulation of the areas of the hypothalamus, located near the arch in preoptions region, in the ventral part of the bulkhead and in the Central gray matter, causes a defensive reaction of the animals. It turned out that the reaction of false rage caused by stimulation of the hypothalamus and thalamus, can be modified by irritation of the amygdala, the hippocampus or pear-shaped share. Seizures caused by irritation of the hippocampus, accompanied by the significant decrease of the reaction threshold of rage cats that imaginary rage occurs even when a light touch to animal [Mac lane (P. D. Mac Lean)].
A similar type of reaction can be observed in case of irritation or delete the temporal pole or cingulate gyrus.
Removing temporal lobes causes animals characteristic of the disorder known as syndrome Kluwer - Busi. The most characteristic of this syndrome following characteristics: 1) "visual agnosia" - animals indiscriminately and fear, take in a mouth all in a row, often dangerous objects (nails, lit a match, and so on); 2) hypermetabolic - increasing trends to examine the subject visually and tactile; 3) the animals become tame, lose the fear; 4) changing attitudes to diet - preferred meat food; 5) sexual addiction.
De Molina, Hunsberger (F. A. de Molina, R. W. Hun sperger) investigated almond kernel, the next part of the hippocampus, and the path connecting them with area of partitions and hypothalamus, and showed the presence of a finely organized neural substrate for the individual components of a defensive reaction (Fig. 1). Damage cingulate gyrus also make the animals manual. Thus, the emotional stimulation caused by integrated complex of cortical-subcortical closely connected devices.

Fig. 1. A schematic representation of the areas of the front and middle of the brain of a cat, if symptoms are experiencing affective reactions (de Molina and Hunsperger). The active portion of the hypothalamus and mid-brain consists of ((inner zone (black), irritation which can cause a reaction hiss, and "external" zone (hatch in the box), the irritation which occurs escape response. Active area almond kernel, the stria terminalis and the bed of the stria terminalis (cross-hatching), in case of irritation, which is called the reaction growl: 1 - almond kernel; 2 - front komissara; 3 - bed of the stria terminalis; 4 - the downward elbow of the code; 5 - stria terminalis; 6 - fimbria; 7 - the hippocampus; 8 - the Central gray matter middle brain; I am the hypothalamus.

Fig. 2. The scheme of the limbic system of the brain and its connections (Crete): 1 - the hippocampus; 2 - dentate gyrus; 3 - the amygdala; 4 - terminal strip; 5 - the brain stem; 6 - brain strip; 7 - medial forebrain bundle; 8 - Minikowo the kernel; 9 - mamillaria body; 10 - diagonal site Broca; 11 - olfactory tract; 12 - medial strip; 13 - lateral strip; 14 - partition; 15 - front thalamus; 16 - REDD; 17 - corpus callosum; 18 - nodrosinata strip.

This system, on the basis of which played an emotional excitement, was named Mac lane's limbic system of the brain (Fig. 2). In the opinion of Gellhorn (I.e. Gellhorn), Central role in this system belongs to the hypothalamus. Now firmly established that the hypothalamic centers, as the reticular formation of the brain stem, have the ability to provide the cortex of the brain ascending activating influence (Fig. 3). These effects are sold through an extensive system of relations of the hypothalamus with the structures of the limbic system, through the medial forebrain bundle, and also through communication with the reticular formation of the middle brain.
It is through such bottom-up influences is functional Association cortical-subcortical vehicles, mechanisms of formation of emotions. However, these systems provide another important property: the excitement in them due to the cyclical relationship can circulate through various structures, which leads to a significant increase and strengthening tonic strong emotions and is therefore able to give it a protracted or even pathologically chronic. An example of such cyclic interactions can be two rounds of the limbic system (Fig. 4).

Fig. 3. Changes in the electrical activity of the brain during irritation ventromedial nuclei of the hypothalamus rabbit: 1 and 2 - EEG with the right and left sensorimotor areas; 3 and 4-EEG with the right and left occipital region. The time of stimulation of the hypothalamus are marked by arrows. Below is the scheme of the ascending activating effects of the hypothalamus in the cerebral cortex and the reticular formation of the middle brain: Mr. hypothalamic region; the Russian Federation - the reticular formation of the brain stem.
Fig. 4. The scheme circular relationships medial forebrain bundle with limbic cortex, hypothalamus and reticular formation of middle brain (on Mac lane): the top drawing - afferent connections; lower - efferent communication; 1 - the amygdala; 2 - a wall; 3 - singulyarnaya furrow; 4 - singularly beam; 5 - REDD; 6 - front thalamus; 7 - medial forebrain bundle; 8 - olfactory tract; 9 - diagonal site Broca; 10 - dystonia; 11 - mamillaria body; 12 - pituitary; 13 - limbic field of middle brain Nauty; 14 - grey matter middle brain; 15 - top geniculate; 16 - ventral and dorsal nucleus tires Gudena; 17 - bridle; 18 - Minikowo the kernel.

One of them is the so-called amidamary circle, starting in the hypothalamus, through the medial forebrain bundle is directed to amigdalou area where converges with fibers going from lateral olfactory tract. From the amygdala fiber distributed to bark prednisone region. Another circle - septal - routed from the hypothalamus medial to the field of partitions, where converges with fibers running from the medial olfactory tract. Hence fiber through the set is distributed in the hippocampus and singulyarno region. Mac lane believes that patterns amigalama circle provide such vital reactions as food, protective reactions (pain, fear), while the structure of septal circle mainly associated with animals, and humans sexual reactions.
The limbic system is also close functional relationship with the Central gray matter and reticular formation of middle brain (the middle cerebral limbic field). Thanks so extensive subcortical relations emotional discharge is able to cover all the functions of the body.
The role of the cerebral cortex is also important in the formation of emotions. This applies above all to phylogenetically old bark (printing. table). Damage or destruction of these departments of a bark abruptly changes emotional reactivity, reducing or, on the contrary, strengthening it.

Phylogenetically old bark and its relationships established method strychnine neutronography (on Mac lane): 1 - the outer surface of the brain of a monkey; 2 - mediobasal surface. Black boxes show the points of application of strychnine; point - the zone of distribution of excitation from paragraph applications; the arrow in the direction of propagation of an excitation (arrow with the two ends of the link reciprocal interacting region).

Thus, the hypothalamic-limbic system in interaction with the reticular formation of the brain stem is the Central nervous substrate emotions. Subjective feeling arises as a result of excitation of the system. It can be caused by the influence coming from the periphery (on the example of formation of pain), and again, after the situation assessed the activity of cortical cells. This is followed by repeated repeated activation interrelated limbic and cortical cells.
The attitude of the limbic system to the formation of emotional States proved by experiments with self-irritation [olds (J. Olds and Milner (P. Milner), 1954], in which the animals themselves the opportunity to cause electrical their irritation of the nerve centers by pressing a lever, closing the chain of the electric current. Were defined the positive zone, while the tip of the electrode in which animals perform multiple re samorazdrazheniya and negative zones, random irritation which never lead in future to samorazdrazheniya (Fig. 5).

Fig. 5. Positive (points) and negative (hatch) zones of samorazdrazheniya (Olds): 1 - corpus callosum; 2 - the hippocampus; 3 - front thalamus; 4 - the lid of the middle brain, 5 - REDD; 6 - medial thalamus; 7 - the hypothalamus, S - mid centre; 9 - preparatory bark; 10 - the amygdala.