The auditory zone functions as the sensory zone. Physiology of the cerebral cortex. Sensory, motor and associative areas of the cerebral cortex. Functional areas of the cortex

FUNCTIONAL ORGANIZATION OF THE LARGE HEMISPHERES CORTEX

Depending on the functions performed, the cortical areas are divided into:

Sensory

Motor

Associative

The sensory areas include: the somatosensory cortex, which occupies the posterior central gyrus, the visual cortex, located in the occipital lobes, and the auditory cortex, which occupies part of the temporal lobes.

The motor cortex is located in the anterior central gyri and in the regions of the frontal lobes adjacent to them in front.

The association cortex occupies the entire remaining surface of the brain, it is divided into the prefrontal cortex of the frontal lobes, the parietotemporo-occipital and limbic cortex, which includes the inner and lower surfaces of the frontal lobes, the inner surfaces of the occipital lobes and the lower parts of the temporal lobes.

Different areas of the cortex interact with each other through associative connections or with the help of subcortical structures (thalamus, basal ganglia). Regions of the cortex located in different hemispheres are connected to each other by fibers of the corpus callosum, which allows information to be transferred from one hemisphere to the other.

Question_1

Sensory cortex

Definition_1

The sensory cortex is the area of ​​the cerebral cortex in which sensory stimuli are projected (synonyms: projection cortex or cortical part of the analyzers).

The sensory cortex is located primarily in the parietal, temporal and occipital lobes of the cerebrum.

All sensory systems are organized according to a single hierarchical principle. In their receptors, the energy of external stimuli is converted into electrochemical energy of nerve impulses, which are transmitted from sensory neurons to second-order neurons located in the central nervous system.

After converting signals at the lowest switching level with the help of relay neurons, the information is communicated to the next level of switching and processing until it enters the primary projection cortex.

The topographic ordering of neural switching provides a spatial representation or projection of receptive fields in the cortex in the form of a neural map. For example, each square millimeter of the skin surface of any of the fingers has its own representation in a strictly defined area of ​​the postcentral gyrus of the opposite hemisphere.

The principle of strictly ordered organization in the somatosensory system is called somatotopy, in the visual system - retinotopy, in the auditory system - tonotopy.

Sensory systems create sensations and perceptions of the surrounding world, control the correctness of human movements, are used as feedback to regulate physiological processes, and support the brain activity necessary for wakefulness.

Afferent pathways to the sensory cortex come predominantly from specific sensory nuclei of the thalamus.

Areas of the sensory cortex include:

Primary sensory areas - consist of neurons that form sensations of the same quality;

Secondary sensory areas - consist of neurons that form sensations that arise in response to the action of several stimuli.

Let us consider the primary sensory areas of the cerebral cortex.

1 The parietal cortex of the postcentral gyrus is the primary somatosensory area. Here are the projections:

Skin sensitivity from tactile, pain temperature receptors;

Sensitivity of the musculoskeletal system - muscles, joints, tendons;

Tactile and taste sensitivity of the tongue.

2 The cortex of Heschl’s transverse temporal gyrus is the primary auditory sensory area. In this zone, in response to irritation of the auditory receptors of the organ of Corti, sound sensations are formed. Different areas of the cortex represent different areas of the organ of Corti. The center of the vestibular analyzer is localized here - in the superior and middle temporal gyrus. The processed information is used to form a “body schema” and regulate cerebellar function, forming the temporocerebellar tract.

3 Cortex of the sphenoid gyrus and lingual lobe, area 17 - primary visual area located in the occipital cortex. There is a representation of retinal receptors, and each point of the retina corresponds to its own section of the visual cortex. Above is the secondary visual area (fields 18 and 19). The neurons of these zones are polymodal, responding not only to light stimulation, but also to tactile auditory stimulation. Here a synthesis of different types of sensitivity occurs, and more complex visual images arise.

As an example of a secondary sensory area, consider the secondary visual cortex, which is adjacent to the primary visual cortex and occupies fields 18 and 19 of the occipital lobes.

About 30 regions involved in the processing of visual information are concentrated in this area. They differ in the function they perform, for example, mediotemporal region carries out the processing of information about the movement of an object in the visual field, and the region located at the junction of the parietal and temporal regions provides the perception of the shape and color of the object.

There are two pathways designed for separate processing of visual information, the upper and lower pathway. Bottom path passes to the inferior temporal gyrus, where neurons with large receptive fields are found.

There is no retinotopic organization in this area; visual stimuli are recognized in it, their shape, size and color are established. Here there are face-specific neurons that selectively respond to the appearance of a person’s face in the visual field, and some neurons are activated if the face is turned in profile, while others respond to a frontal turn. If this area is affected, it may occur prosopagnosia, in which a person ceases to recognize familiar faces.

In the middle, as well as in the superior temporal gyrus, there are neurons necessary for the perception of moving objects and for fixating attention on stationary objects.

Upper path from the primary visual cortex leads to posterior parietal areas. Its functional significance lies in determining the relative spatial location of all simultaneously acting visual stimuli. Damage to this area of ​​the cortex leads to a defect in spatial sensations and impaired visual-motor reactions; a person sees an object and can correctly describe its shape and color, but when trying to take this object with his hand he misses.

For ease of remembering, the lower path is usually associated with the question, “ What?" represents the object, and the top path represents the question, " Where?» this object is located.

Function of the somatosensory cortex. The central processes of primary sensory neurons, transmitting signals from tactile receptors of the skin and from proprioceptors of muscles, tendons and joints, enter the spinal cord through the dorsal roots and form collaterals, which, as part of the posterior columns of the spinal cord, reach the medulla oblongata. Incoming signals are received by neurons of the dorsal column nuclei, the axons of which immediately move to the opposite side of the medulla oblongata as part of the medial lemniscus or medial lemniscus(thanks to this term, the entire path received the name lemniscus) and are directed to posterior nucleus of the thalamus. The same nucleus of the thalamus receives information from the skin of the opposite side of the face, transmitted along the branches of the trigeminal nerve.

Neurons of the thalamic nuclei form a projection to posterior central gyrus, which represents the projection somatosensory area. Thus, a map of somatosensory representation in the cortex is formed - sensory homunculus, i.e., projection fields corresponding to the innervation of areas of the human body.

Sensory zones are the central sections of the analyzers. They do not have clearly defined boundaries and somewhat overlap each other at the periphery. When affected, a loss of certain sensitivity occurs.

Primary sensory areas of the cortex, where the projection fibers of the afferent systems end.

1. The first somatosensory area is the postcentral gyrus, behind the Rolandic sulcus. This is the cortical projection of the skin sensitivity systems and the sensitivity of the motor apparatus.

Different parts of the body have a clear spatial (tonic) representation in it. Moreover, the area onto which the surface of the most sensitive areas of the body is projected - lips, tongue, fingertips - is almost the same in size as the area representing the entire body (the number of receptors is approximately the same).

2. The second area of ​​somato-sensory sensitivity located more ventrally (in the area of ​​the Sylvian fissure).

Core and periphery.

The largest size is the sensory area of ​​the hand, vocal apparatus and face. The smallest - torso, thighs, legs.

Flavoring- in the parietal lobe in the lower part of the posterior central gyrus.

Olfactory– structures of old and ancient bark.

2) The first visual area is field 17 (inner surface of the occipital cortex).

There is an exact topical representation of the peripheral receptive field of the retina. Each point on the retina corresponds to a site in the visual cortex to which it is projected. In mammals, due to the peculiarity of the crossover of the visual pathways, the same halves of the retinas are projected into each hemisphere (i.e., to the left - both right halves, to the right - both left halves), therefore the visual fields of both eyes seem to overlap each other in each hemisphere . This is the basis of binocular vision, providing the ability to see everything in the singular and in volume.

Second visual area (field 18) - connection with eye movements

Third visual area (field 19)

First auditory zone (fields 41 and 42) inferior surface of the Sylvian fissure.

Parts of the organ of Corti of the cochlea are represented in its different parts.

The second zone is in the ectosylvian gyrus (below the first). The third is on the island.

4) The localization of the taste analyzer region is less clear. It is assumed that in areas of the postcentral gyrus they coincide with the tactile sensitivity of the tongue. This is the lower part of the postcentral gyrus, area No. 43. Destruction of projection zones leads to loss of corresponding sensitivity. When irritated, corresponding sensations appear. In this case, irritation of the primary areas is caused by simple sensations, while the secondary ones are caused by much more complex ones.

Motor areas – irritation of which causes clear and constant motor effects.

The first motor area is the precentral gyrus (fields 4 and 6) in primates.

The supplementary motor area is medial on top of the cortex.

Topical localization of motor functions is characteristic. It roughly coincides with the spatial organ of the somatosensory zone. A very large area determines the movements of the fingers, facial muscles and tongue muscles, and a much smaller one - the muscles of the trunk and lower extremities.

Removal of the motor cortex causes impairment of motor function, but it is quickly restored. The depth of the disruption is extremely dependent on how the destruction was carried out. If the entire area is removed bilaterally, it leads to severe, difficult-to-reversible processes, and voluntary movements are impaired. Unilateral removal - violations are gradually erased. It is obvious that there are close connections between the motor areas of the hemispheres, providing greater opportunities for plasticity and compensation of motor functions.

Moreover, the complete removal of one hemisphere in children 4-5 years old (due to dropsy of the brain, for example) leads after a few years to almost complete compensation of functions (at first glance they are indistinguishable). In adults, there is no effective compensation.

The two hemispheres that make up the forebrain act in concert. The right hemisphere controls the sensory and motor functions of the left half of the body, and the left exerts similar control over the right half. The connection between the visual areas of the left and right hemispheres is normally carried out through the corpus callosum.

Functionally, there are three types of cortex:

sensitive (sensory), motor (motor) and associative

The sensory cortex is responsible for processing information from the senses.

It is in it that the cortical sections of the human analyzers are located: in the occipital region - visual, in the temporal region - auditory, in the parietal region - cutaneous, etc.

The first neurons that control the functioning of human voluntary muscles are located in the motor cortex. Each muscle group corresponds to a specific area of ​​the motor cortex

The overwhelming majority of the cortical area is occupied by the associative cortex. As most scientists believe, it is there that associative connections between specialized areas are formed and the information coming from them is integrated. In addition, it is believed that current information is combined with emotions and memories, which allows people to think, decide, and make plans.

Sensory areas

The cortical ends of the analyzers have their own topography and certain afferents of the conducting systems are projected onto them. The cortical ends of the analyzers of different sensory systems overlap. In addition, in each sensory system of the cortex there are polysensory neurons that respond not only to “their” adequate stimulus, but also to signals from other sensory systems.

The cutaneous receptive system, thalamocortical pathways, project to the posterior central gyrus. There is a strict somatotopic division here. The receptive fields of the skin of the lower extremities are projected onto the upper sections of this gyrus, the torso onto the middle sections, and the arms and head onto the lower sections.

Pain and temperature sensitivity are mainly projected onto the posterior central gyrus. In the cortex of the parietal lobe (fields 5 and 7), where the sensitivity pathways also end, a more complex analysis is carried out: localization of irritation, discrimination, stereognosis.

When the cortex is damaged, the functions of the distal parts of the extremities, especially the hands, are more severely affected.

The visual system is represented in the occipital lobe of the brain: fields 17, 18, 19. The central visual pathway ends in field 17; it informs about the presence and intensity of the visual signal. In fields 18 and 19, the color, shape, size, and quality of objects are analyzed. Damage to field 19 of the cerebral cortex leads to the fact that the patient sees, but does not recognize the object (visual agnosia, and color memory is also lost).

The auditory system is projected in the transverse temporal gyri (Heschl's gyrus), in the depths of the posterior sections of the lateral (Sylvian) fissure (fields 41, 42, 52). It is here that the axons of the posterior colliculi and lateral geniculate bodies end.

The olfactory system projects to the region of the anterior end of the hippocampal gyrus (field 34). The bark of this area has not a six-layer, but a three-layer structure. When this area is irritated, olfactory hallucinations are observed; damage to it leads to anosmia (loss of smell).

The taste system is projected in the hippocampal gyrus adjacent to the olfactory area of ​​the cortex (field 43).

Motor areas

For the first time, Fritsch and Gitzig (1870) showed that stimulation of the anterior central gyrus of the brain (field 4) causes a motor response. At the same time, it is recognized that the motor area is an analytical one.

In the anterior central gyrus, the zones whose irritation causes movement are presented according to the somatotopic type, but upside down: in the upper parts of the gyrus - the lower limbs, in the lower - the upper.

In front of the anterior central gyrus lie premotor fields 6 and 8. They organize not isolated, but complex, coordinated, stereotypical movements. These fields also provide regulation of smooth muscle tone and plastic muscle tone through subcortical structures.

The second frontal gyrus, occipital, and superior parietal regions also take part in the implementation of motor functions.

The motor area of ​​the cortex, like no other, has a large number of connections with other analyzers, which apparently determines the presence of a significant number of polysensory neurons in it.

Associative areas

All sensory projection areas and the motor cortex occupy less than 20% of the surface of the cerebral cortex (see Fig. 4.14). The rest of the cortex constitutes the association region. Each associative area of ​​the cortex is connected by powerful connections with several projection areas. It is believed that in associative areas the association of multisensory information occurs. As a result, complex elements of consciousness are formed.

Association areas of the human brain are most pronounced in the frontal, parietal and temporal lobes.

Each projection area of ​​the cortex is surrounded by association areas. Neurons in these areas are often multisensory and have greater learning abilities. Thus, in associative visual field 18, the number of neurons “learning” a conditioned reflex response to a signal is more than 60% of the number of background active neurons. For comparison: there are only 10-12% of such neurons in the projection field 17.

Damage to area 18 leads to visual agnosia. The patient sees, walks around objects, but cannot name them.

The polysensory nature of neurons in the associative area of ​​the cortex ensures their participation in the integration of sensory information, the interaction of sensory and motor areas of the cortex.

In the parietal associative area of ​​the cortex, subjective ideas about the surrounding space and our body are formed. This becomes possible due to the comparison of somatosensory, proprioceptive and visual information.

Frontal associative fields have connections with the limbic part of the brain and are involved in organizing action programs during the implementation of complex motor behavioral acts.

The first and most characteristic feature of the associative areas of the cortex is the multisensory nature of their neurons, and not primary, but rather processed information is received here, highlighting the biological significance of the signal. This allows you to formulate a program of targeted behavioral act.

The second feature of the associative area of ​​the cortex is the ability to undergo plastic rearrangements depending on the significance of incoming sensory information.

The third feature of the associative area of ​​the cortex is manifested in the long-term storage of traces of sensory influences. Destruction of the associative area of ​​the cortex leads to severe impairments in learning and memory. The speech function is associated with both sensory and motor systems. The cortical motor speech center is located in the posterior part of the third frontal gyrus (area 44), most often in the left hemisphere, and was described first by Dax (1835) and then by Broca (1861).

The auditory speech center is located in the first temporal gyrus of the left hemisphere (field 22). This center was described by Wernicke (1874). The motor and auditory speech centers are interconnected by a powerful bundle of axons.

Speech functions associated with written speech - reading, writing - are regulated by the angular gyrus of the visual cortex of the left hemisphere of the brain (field 39).

When the motor center of speech is damaged, motor aphasia develops; in this case, the patient understands speech, but cannot speak himself. If the auditory center of speech is damaged, the patient can speak, express his thoughts orally, but does not understand someone else's speech, hearing is preserved, but the patient does not recognize words. This condition is called sensory auditory aphasia. The patient often talks a lot (logorrhea), but his speech is incorrect (agrammatism), and there is a replacement of syllables and words (paraphasia).

Damage to the visual center of speech leads to the inability to read and write.

An isolated writing disorder, agraphia, also occurs in cases of dysfunction of the posterior parts of the second frontal gyrus of the left hemisphere.

In the temporal region there is field 37, which is responsible for remembering words. Patients with lesions in this field do not remember the names of objects. They resemble forgetful people who need to be prompted with the right words. The patient, having forgotten the name of an object, remembers its purpose and properties, so he describes their qualities for a long time, tells what they do with this object, but cannot name it. For example, instead of the word “tie,” the patient, looking at the tie, says: “this is something that is put on the neck and tied with a special knot so that it is beautiful when they go to visit.”

The distribution of functions across brain regions is not absolute. It has been established that almost all areas of the brain have polysensory neurons, that is, neurons that respond to various stimuli. For example, if field 17 of the visual area is damaged, its function can be performed by fields 18 and 19. In addition, different motor effects of irritation of the same motor point of the cortex are observed depending on the current motor activity.

If the operation of removing one of the zones of the cortex is carried out in early childhood, when the distribution of functions is not yet rigidly fixed, the function of the lost area is almost completely restored, i.e. in the cortex there are manifestations of mechanisms of dynamic localization of functions that make it possible to compensate for functionally and anatomically damaged structures.

An important feature of the cerebral cortex is its ability to retain traces of excitation for a long time.

Trace processes in the spinal cord after its irritation persist for a second; in the subcortical-stem regions (in the form of complex motor-coordinating acts, dominant attitudes, emotional states) last for hours; in the cerebral cortex, trace processes can be maintained according to the feedback principle throughout life. This property gives the cortex exceptional importance in the mechanisms of associative processing and storage of information, accumulation of a knowledge base.

The preservation of traces of excitation in the cortex is manifested in fluctuations in the level of its excitability; these cycles last 3-5 minutes in the motor cortex and 5-8 minutes in the visual cortex.

The main processes occurring in the cortex are realized in two states: excitation and inhibition. These states are always reciprocal. They arise, for example, within the motor analyzer, which is always observed during movements; they can also occur between different analyzers. The inhibitory influence of one analyzer on others ensures that attention is focused on one process.

Reciprocal activity relationships are very often observed in the activity of neighboring neurons.

The relationship between excitation and inhibition in the cortex manifests itself in the form of so-called lateral inhibition. With lateral inhibition, a zone of inhibited neurons is formed around the excitation zone (simultaneous induction) and its length, as a rule, is twice as large as the excitation zone. Lateral inhibition provides contrast in perception, which in turn makes it possible to identify the perceived object.

In addition to lateral spatial inhibition, in cortical neurons, after excitation, inhibition of activity always occurs, and vice versa, after inhibition - excitation - the so-called sequential induction.

In cases where inhibition is unable to restrain the excitatory process in a certain zone, irradiation of excitation occurs throughout the cortex. Irradiation can occur from neuron to neuron, along the systems of associative fibers of layer I, and it has a very low speed - 0.5-2.0 m/s. In another case, irradiation of excitation is possible due to axon connections of pyramidal cells of the third layer of the cortex between neighboring structures, including between different analyzers. The irradiation of excitation ensures the relationship between the states of the cortical systems during the organization of conditioned reflex and other forms of behavior.

Along with the irradiation of excitation, which occurs due to impulse transmission of activity, there is irradiation of the state of inhibition throughout the cortex. The mechanism of irradiation of inhibition is the transfer of neurons into an inhibitory state under the influence of impulses coming from excited areas of the cortex, for example, from symmetrical areas of the hemispheres.

IN cerebral cortex afferent impulses arrive from all receptors of the body. The direct transmitting station of these impulses to the cortex (with the exception of impulses coming from the olfactory receptors) are the nuclei and the formation adjacent to it, where the third neurons of the afferent pathways are located (p. 542). I. P. Pavlov called the areas of the cortex into which afferent impulses predominantly arrive the central sections of the analyzers.

Representation of somatic and visceral sensitivity. In each hemisphere there are two zones representing somatic (cutaneous and joint-muscular) and visceral sensitivity, which are conventionally called the I and II somatosensory zones of the cortex. The first somatosensory cortex is located in the posterior central gyrus.

Its size is much larger than the second one. This zone receives afferent impulses from the posterior ventral nucleus of the thalamus, delivering information received by cutaneous (tactile and temperature joint-muscular and visceral receptors on the opposite side of the body. On rice. 247 The location of projections of various parts of the human body in this zone is shown. As you can see, the largest area is occupied by the cortical representation of the receptors of the hand, vocal apparatus and face, the smallest area is occupied by the representation of the trunk, thigh and lower leg. Rice. 247. Location of projections of various parts of the body in the somatosensory zone of the human cerebral cortex (according to W. Penfield and Rasmussen). 1 - genitals; 2 - fingers; 3 - foot; 4 - shin; 7 - neck; 8 - head; 9 - shoulder; 10 - elbow joint; 11 - elbow; 12 - forearm; 13 - 15 - little finger; 17 - middle finger; 18 - index finger; 19 - thumb; 21 - nose; 22 - face; 24 - teeth; 25 - lower lip; 26 - teeth, gums and jaw; 27 - language; 28 - pharynx; 29 - internal organs. The sizes of body parts correspond to the sizes of sensory representation

The area of ​​the cortical projection is determined by the number of nerve cells of the cortex involved in the perception of stimulation from a particular receptor field. The greater the number of cells, the more differentiated the analysis of peripheral irritations. Cortical projections of receptors of visceral afferent systems (digestive tract, excretory apparatus, cardiovascular system) are located in the area where skin receptors are represented in the corresponding areas of the body.

The second somatosensory zone is located under the Rolandic fissure and extends to the upper edge of the Sylvian fissure; afferent impulses to this zone also come from the posterior ventral nucleus of the thalamus.

Representation of visual reception. The cortical ends of the visual analyzer, the so-called visual zones, are located on the inner surface of the occipital lobes of both hemispheres in the area of ​​the calcarine sulcus and adjacent gyri. The visual zones are a projection of the retina. Afferent impulses enter this area from the external geniculate bodies, where the third neurons of the visual pathway are located.

Representation of auditory reception. The cortical ends of the auditory analyzer are localized in the first temporal and so-called transverse temporal gyri of Heschl. Afferent impulses enter this zone from the cells of the internal geniculate tract) and carry information from the bodies (the third neurons of the auditory mulberry receptors of the cochlea of ​​the inner ear. Impulses arising in the receptors of the cochlea when perceiving tones of different pitches enter various groups of cells in the auditory zone.

Representation of the taste department. The cortical ends of the taste analyzer, according to Penfield, are located in humans in the temporal lobe near the area of ​​the cortex, the irritation of which causes salivation. Afferent impulses enter the taste zone from the inferior posterior nucleus of the thalamus.

Representation of olfactory reception. The olfactory sensory pathways are the only afferent pathways that do not pass through the nuclei of the visual thalamus. Their first neurons - olfactory cells - are located in the nasal mucosa. The second neurons are located in the olfactory bulb. The processes of the second neurons form the olfactory tract, which reaches the cells located in the anterior part of the piriform lobe (L. Brodal), where the cortical end of the olfactory analyzer is located.

Effects of irritation and destruction of sensory areas in humans. The localization of sensory zones in humans has been studied mainly by the method of electrical stimulation of various points of the cortex during brain operations. Since such operations are performed under local anesthesia, the patient can give an accurate verbal description of the sensations he experiences. The latter, as shown by detailed studies conducted by Penfield et al., are always of an elementary nature. Thus, when the visual zone is irritated, a person experiences sensations of flashes of light, darkness and various colors. No complex visual hallucinations are observed when this area is stimulated. Irritation of the auditory cortex causes sensations of various sounds, which can be high and low, loud and quiet; however, the patient never experiences speech sounds with electrical stimulation. Irritation of the somatosensory zone causes sensations of touch, tingling, numbness, and less often a weak temperature or pain sensation. Severe pain is almost never observed. When the olfactory or gustatory zone is irritated, various smell or taste (mostly unpleasant) sensations arise.

Destruction of sensory zones in humans usually leads to gross disturbances of this type of sensitivity on the side of the body opposite to the lesion. Bilateral damage to the visual zones leads to complete blindness, and removal of the auditory zones leads to deafness. Dysfunctions of sensory zones in humans due to hemorrhage, tumor, or injury are compensated much worse than in animals. Based on experiments conducted on dogs with the removal of different areas of the cerebral cortex. I. P. Pavlov came to the conclusion that at the cortical end of each analyzer one should distinguish between the central part, or core, and the so-called scattered elements. By these elements he understood nerve cells located in a wide area, which receive impulses from the same receptors as in the analyzer core. The presence of scattered elements provides the ability to compensate for the function in the event of destruction of the analyzer core. In humans, compensation of functions is less pronounced, probably because the nerve cells of the cortical ends of the analyzers are more concentrated in the sensory areas.

The sensory cortex is a small part of the brain located between the motor cortex and the parietal lobe. It is this part of the brain that is responsible for bodily sensations and perceptions. All our tactile, visual, auditory and olfactory impulses are born in the sensory area of ​​the cerebral cortex. The maximum concentration of cerebrospinal fluid is achieved where we had a fontanel in childhood. Taoists believe that the hardening of this soft area begins the process by which we experience each sensation as its own. As children, we feel external stimuli, but are not able to recognize each sensation separately.

Taoists call this area a cavity Bai Gui, in which, when experiencing intense mental states, all sensations are concentrated and the mind can comprehend absolute purity - enlightenment of consciousness.

In Taoism, this area of ​​the brain is stimulated both by visualizing light at the crown of the head and by gazing at it with the inner eye, the purpose of which is to increase its level of perception. This zone is important not only from the point of view of restoring youth and achieving enlightenment of consciousness, but also because it is through it that the spirit leaves the body at the moment of death.

When the sensory cortex is intensely stimulated, the body's ability to receive physical and mental sensations is greatly enhanced. This increased sensitivity to sensation is also reflected in the hypothalamus' response to intense sexual arousal; The hypothalamus sends a signal to the pituitary gland to release gonadotropins into the endocrine system.

This occurs only if the person has experienced some intense state of ecstatic nature, which underlies almost all transcendental experiences described in treatises on meditation and yoga. Sex, being a source of energy, provides the best and most effective means to experience such a state.

The spinal cord and brain are entirely surrounded by cerebrospinal fluid, and it is this fluid, according to Taoists, that is responsible for the passage of sexual energy from the kidneys to the brain. The effect of enlightenment is caused by a combination of increased blood temperature and the movement of sexual energy reaching the top of the head. Don't forget that quite a lot of this fluid is located in the sensory area of ​​the cerebral cortex.

Both Tigresses and Taoists strive to stimulate the sensory cortex. The methods may differ somewhat, but the end goal is the same. The tigress achieves enlightenment of consciousness by absorbing male sexual energy, which in Taoist books is called the restoration of yin through yang. A Taoist man achieves enlightenment by returning sexual energy to the brain, or restoring yin through yang.

The Tigress, through full concentration on oral stimulation of the man's penis, can achieve a state of supreme receptivity, the result of which is the ability of the Tigress to absorb male sexual energy and experience spiritual transformation. The main point is to enhance the stimulation of the pituitary gland and hypothalamus so that they respond to the limit of their capabilities and produce hormones that can restore youth.

Orgasm

Having discussed how Western science and Taoist spiritual alchemy view the process of energy absorption, we can now talk in more detail about orgasm itself.

Immediately before or immediately after orgasm, the human consciousness is in a state of heightened receptivity. During orgasm, time stops and the entire nervous system focuses on sensations and the release of sexual fluids.

The more intense the orgasm, the richer and brighter the sensations and perceptions.

Orgasm also actively stimulates the occipital lobe of the brain (which controls vision) and reduces the activity of the motor cortex (which controls voluntary movements). During orgasm, we perceive and feel the world around us through highly concentrated sensations. Colors seem brighter to us, and our consciousness is filled with luminous images. The body no longer controls voluntary movements, but only makes those that contribute to orgasm. Even the auditory and speech centers of the brain are in a state of increased activity.

As for increasing the acuity of hearing and vision, many sexual failures occur precisely because the sexual partner says some inappropriate words during the orgasm of the second partner. A person at this moment is so sensitive that words of insult or disapproval sink very deeply into the consciousness and affect his sexual behavior in the future. This is why, as you will learn later, during sexual intercourse Tigress always shows deep approval of her partner’s penis, the quality of his sperm and his actions.

After orgasm, the entire body enters a state of rest, and therefore most sexologists consider it a tranquilizer. This happens because the pituitary gland, which also controls the production of calming hormones, immediately sends them to the endocrine system, which is the body's natural defense against too intense and prolonged sensations. The reaction to calming hormones is more pronounced in men than in women, since the latter’s body is better adapted to multiple orgasms; Usually, more than one orgasm is required for the pituitary gland to release calming hormones into the female body. This explains the fact that women can be very energetic after orgasm because they are still under the influence of gonadotropins.

Men can also have multiple orgasms, but this only happens when subsequent stimulation is intense enough and a certain amount of time passes between orgasm and new arousal, which is necessary for the calming hormones to lose activity. The intensity of the first orgasm determines the amount of dormant hormones released by the pituitary gland into the body.

For men who ejaculate frequently, calming hormones have less and less effect as they age. To test the effects of these hormones, a man must hold back ejaculation for two weeks or so. Then during ejaculation it will be difficult for him not to close his eyes. These calming hormones are necessary to restore male youth, so ejaculation should not occur frequently. After this, during ejaculation, these hormones will have a stronger effect on the entire endocrine system. The tigress benefits not only from her orgasm, but also from her partner's orgasm. By increasing the intensity of a man's orgasm, she can reach a state of supreme receptivity in which she absorbs both his orgasm and his sexual energy. She achieves this by concentrating entirely on the man's maximum arousal and orgasm - in the sense that all her attention is focused on his penis and sperm. Like a child excited and impatient before opening his birthday present, she moans in anticipation of his orgasm. Holding his penis at a distance of five to seven centimeters from her face, she looks directly at the head of the penis, and when the sperm is released, she imagines how the energy of his orgasm penetrates right into the top of her head. When the man finishes ejaculating, she closes her eyes and moves the pupils up and down, as if looking closely at the upper part of the brain. She turns all her attention to the feeling of the warmth of his seed on her face. With the head of his penis in her mouth, she sucks nine times (very gently and without force if the penis is too sensitive) and again imagines the energy of his penis penetrating into the top of her head.

In these practices she makes full use of her imagination. As we age and experience environmental and social pressures, we lose the ability to use our imagination. Imagination is one of the most powerful tools that we humans, unfortunately, use too rarely. In childhood, fantasy prevents us from distinguishing imaginary friends from real ones and makes it possible to visually and vividly imagine all our goals and hopes. As we age, we use our imagination less and less, although it is involved in the formation of religious experiences: we perceive our god as a real, living person. In this regard we call imagination faith, but it functions in exactly the same way.

The child uses imagination more often than rational thinking, which destroys the power of imagination. The white tigress uses her imagination to the fullest and as a result is able to perceive sexual energy as something completely material. We must remember that everything that exists in the world is the material embodiment of an idea.

Just as some successful athletes, businessmen and movie stars dreamed of becoming rich and famous as teenagers, feeling that this would certainly happen, Tigresses imagine and perceive themselves as having already achieved youth and immortality - and are absolutely sure that this is so. and will be. Using her imagination, Tigress is able to increase the intensity of not only her own orgasm, but also that of her partner and recreate the spiritual and physical state of her youth.

Tigress increases the intensity of her sexual sensations by using men called Green Dragons. She does this in order to avoid routine, which is a negative consequence of a long-term sexual relationship with one partner, in whom the intensity of sensations most often gradually decreases over time. Besides, as the proverb goes, intimacy breeds contempt. With one man, her sexual desire will be realized in sex, the purpose of which will be procreation, and not spiritual rebirth. Having lost the desire for rebirth, she can no longer change. Tigress also uses other men to arouse her main partner, the Jade Dragon, so that he, by watching her make love to them, can also increase his orgasm. Thus, increasing the intensity of her orgasm and that of her partner is the key for Tigress to cleanse, preserve and restore youth. From this point of view, sex becomes medicine.