This is more clearly seen when determining the latent periods of development of different levels of the orienting reaction in the period of incessant electrical stimulation of the hypothalamus. However, with the slowing down of the development of the orientation reaction complex and the change in its structure, it is not only the delay of the subsequent behavioral reaction, but also a significant change in its content.
The former integrity, direction, expediency of behavioral manifestations is lost. Thus, in food behavior, this is expressed by the suppression of a fast-directed search, in research and search - by suppressing the main element of this reaction (active examination, looking around, sniffing the surrounding space and objects), in aggressive-defensive - the attack focus is suppressed. And although the motor activity of the animal did not change (or even in some cases facilitated - metamizil , morphine), all actions performed were performed as if automatically, aimlessly, without assessing the environment.
On the background of psihodepressantov such as haloperidol, central anticholinergic agents (metamizil, amizil, scopolamine), stimulation of the amplification initial orientation reaction components can always be obtained again.
But the more complex, final set of orientation reactions, as well as the purposefulness of behavior, were not restored. Separate sharply expressed motor reactions of the type of start-reflex, rapid escape, postural reactions like “tire reactions”, etc. appeared. In the case of aminazine (up to a certain dose range), increased stimulation could reproduce the entire complex of the orienting reaction and subsequent behavior.
From the data, it is clearly seen that as the dose of haloperidol increases, the period from the onset of irritation (this increases “ alarming ” increased respiration, eye movement) to the beginning of the behavioral response (it is preceded by level III of the orientation reaction) increases dramatically. It can be noted that for quite a long time (10-20 s) the animal makes repeated attempts to start some kind of action, which is expressed by periodically repeated cycles of increased respiration, muscle tension. But they do not end with anything. And only after the development of a clear change in posture (level III), i.e. the completion of the whole complex of the orienting reaction, does purposeful behavior begin.
The effect of chlordiazepoxide was characterized not by suppression, but only by a decrease in intensity (up to certain doses), an increase in the latent components of the orienting reaction, and a slowdown in the development (but not inhibition) of the whole complex of subsequent targeted behavior. In this regard, its effect was somewhat reminiscent of aminazin , but unlike the latter, chlordiazepoxide in small doses (3-4 mg / kg) more selectively suppressed emotional arousal.
A prerequisite for identifying the action of substances with psychostimulating properties was the use of weak, above-threshold intensity of irritating stimuli, sufficient, however, to develop the initial manifestations of purposeful behavior. The effect of small doses of caffeine (2–5 mg / kg) was reduced to a sharp reduction in the latency of level III of the orienting reaction. The observed “relief”, however, did not reflect much on the speed or intensity of the targeted behavior.
The effect of phenamine was significantly different from caffeine. Despite a distinct analeptic effect (increased breathing, a slight increase in muscle tone), phenamine (0.05-2 mg / kg) did not affect the intensity and speed of development of a more complex, final orienting reaction complex (level III), but contributed to the appearance of hyperdirectional non-directional convulsive reactions. In large doses (2–5 mg / kg), phenamine exerted a pronounced facilitating effect both on the orienting reaction and on the subsequent specific behavior.
Effect of Zoloft on emotion.
Zoloft (in a limited range of small doses — 0.5–2 mg / kg) accelerated the development of all components of the orientation reaction, which led to a noticeable relief (reduction of the latent period) of the complex of specific behavior. In large doses (3–6 mg / kg), Zoloft , on the contrary, delayed the development of components of the orienting reaction, and its effect in these doses resembled the effect of chlorpromazine . Like Zoloft tranquilizers in large doses, the development of the third level of the orientation reaction and thus the organization of specific behavior was impeded.
The “ alarming ” reaction , both in its behavioral and EEG events, can be caused by electrical stimulation of a very wide range of brain structures. In particular , with the activation of a number of points in the subtalamic womb, a distinct EEG desynchronization , respiratory acceleration, and eye movement occur .
However, even with increased stimulation of the structures of this zone, there is no transition of the “ alarm ” complex to the subsequent behavior. Only inappropriate motor reactions develop. This element of the orienting reaction can be viewed as “ non-asypical ” and associate it with the stimulation of the activating systems of the brain stem and their ascending and descending manifestations.
That is why there was no correspondence between the data on the effect of various pharmacological compounds on the function of the ascending reticular formation (especially on EEG manifestations) and their psychotropic activity.
The data obtained in our laboratory clearly indicate the splitting of the complex of the orienting reaction under the influence of psychotropic drugs (A. V. Waldman , M. M. Kozlovskaya, 1972, 1973; M. M. Kozlovskaya, 1973). The implementation of a targeted behavioral reaction is blocked if the third (second?) Level of the orientational reaction does not develop.
The sensory phase (stage I) is maintained even under the influence of high doses of tranquilizers. The possibility of individual motor fragments of behavior is not excluded. The high sensitivity of the final stages of the formation of an orientation reaction to psychotropic drugs suggests the orientation of psychopharmacological effects on the process of afferent synthesis. An approximate reaction, therefore, can serve as an indirect test for the identification of psychopharmacological activity, since it includes the most important elements of the system of formation of response behavior, whatever it may be.
Since the initial stages of the formation of adaptive, purposeful behavior are associated with different neurophysiological processes, the psychotropic effect of substances may be associated with their influence on the different stages of afferent synthesis. In more detail this can be explained on the example of mogiviopnogo eating behavior.
The holistic behavioral response in its development undergoes a certain evolution. The stages of afferent synthesis, the formation of a plan and an action goal with the inclusion of the mechanisms of energy (emotional) support of the intended action are consistently carried out. The behavioral response is performed with constant inverse afferentation , monitoring the result of the action and the possibility of changing the plan during its implementation.
As a typical model of motivational behavior, we chose eating behavior, the neurophysiological foundations of which are well studied. The implementation of the manifestations of eating behavior is carried out by various structural and functional mechanisms. At the level of the medulla oblongata and the midbrain, simple inborn reflexes such as swallowing and chewing are performed.
At the level of the hypothalamus (predominantly ventro-medial divisions), the so-called trigger mechanisms of nutritional motivation, represented by specific chemo-sensory neurons, are established. Limbic and neocortical structures provide the food procuring act with a purposeful, adapted to the environment, non-stereotypical behavior, during which the set of movements of the animal can vary depending on the specific tasks whose solution is necessary to achieve the goal.
The initial motive for the emergence of goal-directed behavior is the “dominant motivation” - the feeling of hunger, an element of the “launch” of the whole chain, the behavioral process — the “starting afferentation ”, that is, the immediate stimulus that determines the beginning of the action prepared by motivational excitement, need.
In our experiments, the influence of psychotropic drugs on the functional system of motivational behavior was studied in three variants of experiments, which allow to compare the effect of substances on the processes of emergence and realization of motivation in a naturally occurring stimulus (natural “ starvation ” activation), in conditioned-reflex study and in artificial electrical stimulation of hypothalamic trigger zones ).
Electrical stimulation of certain zones of the lateral hypothalamus V of rabbits activates the trigger mechanisms of the food center, causing the dominant food motivation, which in a resolving situation ends with directional eating behavior.
A well-fed rabbit, being in an experimental chamber, where several feeding troughs with different food are located, does not pay any attention to them and slumbers (sits quietly) in one of the corners of the chamber. At the beginning of the electrical stimulation of the “food zone” (if the intensity of the stimulation is high enough), the rabbit has a short orienting reaction, then it immediately rushes to the feeder with the most appetizing food and eats it while the stimulation continues.
Consequently, the formation of an action plan, analysis, choice of feed occurs during the orientation reaction phase. It is usually impossible to divert the animal during its purposeful movement to the feed: the rabbit overcomes obstacles, jumps over the barrier and reaches the goal. The more intense the stimulation, the faster the complex of behavior develops over time.
The initial (sensory) phase of the orientation reaction is manifested by a series of shifts (increased breathing, eye movement, slight pupil dilation, opening of the palpebral fissure). If the motivation (stimulation) is not strong enough, then further events do not develop. According to electrophysiological data (K.V. Sudakov, 1971), during the indicative reaction period, bioelectric changes are observed in the structures of the limbic brain (septum, amygdala, hippocampus , cingulate gyrus, arch and mamillary bodies).
The spread of hypothalamic excitation to these structures is carried out through the medial bundle of the forebrain and does not capture the neocortical zones. With increased irritation, the final phase of the orienting reaction directly passes into purposeful behavior. The type of rabbit posture change already corresponds to its position during the implementation of a targeted behavioral act. For a period of several seconds (according to the intensity of irritation), the stages of assessing the situation, “decision making”, and “action plan” are carried out. According to the bioelectric picture, excitation spreads to the cortex of the big hemispheres.
Summary data on the effect of certain neuropsychotic drugs on various components of eating behavior caused by electrical stimulation of the hypothalamus are presented in Table. 36. Aminazine at a dose of 0.5-1 mg / kg clearly slowed down the development of individual components of the orienting reaction, increased the latent periods of the food search, made it difficult to jump over the barrier to approach the feeding trough, and in doses of 1-2 mg / kg suppressed directional movement to the feeding trough and the act of eating. However, increased irritation restored the full range of eating behavior.
Scopolamine , amisyl in small doses (0.05–0.1 mg / kg) violated the purposefulness of the movement of the animal to the food source. In response to the electrical stimulation of the hypothalamus, the rabbit was alert, lifted, made several movements in the direction of food. However, having reached the obstacle (barrier), either came back or, having jumped over the barrier, inspected another part of the chamber, repeatedly passing by the feeders.
With the "random" approach to the feed could start to eat, but the process of choosing food was violated. In large doses (0.15 mg / kg), scopolamine completely blocked the targeted eating behavior (movement to the feeder, choice of food, the act of eating), without changing the initial manifestations of the orienting reaction and the overall motor activity.
Morphine in small doses (0.05–0.1 mg / kg) inhibited those elements of the food motivational reaction that determined the purposefulness of the behavior: the search for food, the definition of edibility, the choice of food. Locomotor activity is not disrupted, nastorazhivanie and orienting reaction persisted. The motor manifestations of the food act (chewing, biting , licking) were even easier, either occurred apart from the general behavior of the animal, or were directed to inedible objects ( coprophagy , gnawing of wooden, glass and other objects). It was not possible to restore a full-fledged complex of behavior by increasing irritation
Activation of structures located in the more medial parts of the lateral hypothalamus, somewhat behind the median mass, causes in the rabbit not full-fledged food - directed behavior, but only individual motor fragments of it (chewing, biting edible and inedible objects, undirected “search” movements).
Effektorpy manifestations (the so-called "food reaction") were very resistant to the action of psychotropic drugs. Consequently, eating disorder is not due to the suppression of the executive mechanisms of mesodiencephalic level.
With excessively strong activation of the “food zones” of the hypothalamus, the rabbit develops “wolf hunger” (bulimia). He abruptly jumps up, swiftly moves forward, grabs both edible and inedible objects, depending on what gets in his way: the biological expediency of behavior is disturbed.
After the end of stimulation, a state of emotional arousal is maintained for a long time. The studied compounds, even in large doses, do not change the "bulimia", but completely suppress the trace emotional arousal.
Violation motivational behavior when administered small doses of these compounds ne due to the weakening or inhibition mechanisms trnggerpyh food motivation in the lateral hypothalamus, since the animal eats position before writing them in the same volume.
The use of psychotropic drugs for the analysis of the functional content of the orienting reaction associated with eating behavior clearly demonstrates that the implementation of purposeful behavior is blocked, if a third, completing level of orientational reaction does not develop.
Hungry rabbits (24 or 48-hour starvation) were placed in one half of the chamber, separated by a barrier. A set of feeders (bread, oats, cabbage, carrots, water) was exhibited at a certain moment in the distant part of the other half of the chamber. With the advent of food, the rabbit had a short orienting reaction, he fixed the feeders with his eyes, quickly got up, jumped over the barrier and immediately approached one of feeders with preferred feed. In this case, food dominant motivation exists from the very beginning.
Starting afferentation is the appearance of feeders. After completion of afferent synthesis with the formation of a plan of action, the animal realizes behavioral manifestations (jumping over the barrier, approaching the most appetizing food).
Haloperidol violated the implementation of targeted motivational behavior already with the introduction of very small doses (0.04-0.05 mg / kg). The stages of the orienting reaction that occurred on the introduction of feeders changed little. The rabbit quickly headed towards the feeders, however, not completing a purposeful movement, he froze in front of the barrier in a tense posture.
As the dose was increased, the development of the orienting reaction to the feeding of feeders was delayed at the later stages and the rabbit did not make any movements aimed at reaching the feed. The analysis showed that the effect of small doses of haloperidol It is not associated with the suppression of food motivation or a violation of afferent and efferent executive mechanisms.
Effect of chlorpromazine on food behavior.
Aminazin increased the latent periods, the intensity of development of both the search- directed search and the act of eating itself, reducing the amount of food eaten, reducing the overall locomotor activity, which primarily affected the difficulty of overcoming the barrier. However, if the feeder was on the side of the rabbit, he easily reached it and ate the food.
Small doses of scopolamine and amisyl (0.05 mg / kg) particularly clearly suppressed the emotional arousal accompanying excessive food motivation (48-hour starvation). With the introduction of large doses (0.1-0.3 mg / kg), the feeding behavior of the animal changed markedly. Although the introduction of feeders still caused the rapid development of the initial phases of the orientation reaction, which indicated that the ability to perceive the afferent signal was retained, the implementation of the final stage was strongly delayed. 1-2 is made a step in the direction of feed, a rabbit, a kind of "forgetting" target committed actions ne skipped barrier, not suited to independently feed. Nutritional motivation with scopolamine at doses up to 0.15 mg / kg, substantially ne . violated. When placing the feeders directly in front of the rabbit, the act of eating began immediately, the amount of food eaten did not change.
The effect of morphine in many ways resembles the action of scopolamine : in small doses (0.05–0.1 mg / kg), morphine eliminates hyperemotionality caused by excessive motivation, in doses of 0.1–0.3 mg / kg disrupts the purposefulness and expediency of the animal’s actions, however, up to the introduction of 3 mg / kg does not reduce the amount of food eaten, if it is exposed directly in front of the rabbit.
Chlordiazepoxide, even in large doses (15–20 mg / kg), did not inhibit food motivational behavior, but completely eliminated the emotional arousal that occurs when the animal is very hungry. By the influence of the drug, the period of food- searching is shortened , the approach to food and the barrier is accelerated, the amount of food eaten also increases. Choosing feed does not significantly suffer.
With prolonged fasting (48–58 h) in a rabbit, along with a pronounced excitement caused by strong (excessive) food motivation, an emotional state characterized by hyperreactivity and aggressiveness (attack, biting , knocking paws) on non-food objects, a sharp shift of vegetatics (fast breathing, sharp dilated pupils). Unexpected removal of feeders during the implementation of the act of food also causes excitement of the animal: active movement around the chamber (food search), increased breathing, dilated pupils, increased orienting reactions, especially to objects associated with food (hands of the experimenter, empty feeders constantly standing in the chamber , and etc.).
All studied psychotropic drugs in small doses completely eliminated the emotional shift caused by excessive motivation. This effect was especially pronounced when small doses of haloperidol and metamizyl were administered . Chlordiazepoxide also eliminated all manifestations of non-eating behavioral activation. It is seen that certain drugs carry out the "splitting" of the holistic system of a behavioral act. The suppression of emotional arousal without affecting motivational evidence of the independence of both processes.
Conditioned reflex food-producing behavior.
Conditioned reflex food-producing behavior was studied in three variants of the experiment. First option. By a conventional signal (white light), the rabbit jumped over the barrier, ran along one of the two corridors to the ring, pulled the ring, received additional feeding (if the ring was pulled out to a predetermined length - 3 cm), then returned to the other corridor beyond the barrier, where also received reinforcement. A differentiation signal (red light) was not stereotyped and a “sharp” (one-time) non-reinforcement was carried out .
From the standpoint of the functional system of the manifestation of the instrumental reaction (jump, pace, ring twitching) implement the implementation of the plan of behavior to achieve the goal (food reinforcement). In this case, the starting affiliate function was a conditioned signal, and the behavioral reaction was carried out on the basis of a pre-fixed skill. The adequacy of afferent synthesis is tested by the reaction to a differentiation signal. The second part of the reaction (return for the barrier) is carried out without an external signal on the need for a subsequent action, based on the internal plan.
For the quantitative expression of the effect of psychotropic drugs, the time parameters for the performance of individual elements of the reaction were evaluated: the latent period (from the activation of the conditioned signal to the jump), the run time, the number of ring twitches, and the return time for the barrier.
In the intersignal period, the number of spontaneous jumps and the speed of return were recorded , beyond the barrier, as well as the number of true intersignal reactions that resulted in ring tugging. The characteristic behavior of the rabbit during the intersignal period, reflecting the readiness to perform an action, for the fulfillment of which there is a lack of a conditioned signal, was designated as a “waiting reaction” and was scored: 0-rabbit sits in the corner of the chamber, napping; 1 - sits at 10-20 cm from the barrier, does not follow the experimenter; 9 - stands at the barrier, looks at the experimenter, waits; 3 - the rabbit is excited, stands at the barrier, periodically stands on its paws, stretches forward, follows the experimenter. The intensity of the reaction of the rabbit on the acute failure of the correct support of the conditioned reflex behavior was estimated by the number of ring twitches for 15 s, by scratching the feeder and other motor-vegetative manifestations.
This methodical technique, developed in our laboratory by N. V. Petryaevskaya and B. V. Andreev (1974), is very convenient for psychopharmacological studies, since it makes it possible to judge the functioning of a number of systems. The implementation of the instrumental response complex is strictly regulated by a given program, the violation of which leads to the absence of reinforcement, which causes the animal to correct the error.
The experimenter has the opportunity to judge the adequacy of afferent synthesis by intersignal reactions, a differentiation signal, by the adequacy of the action plan (running along a predetermined corridor, ring pulling at a predetermined length, returning to the barrier after the feed), the function of the error detection system (return speed after jumping the barrier in the intersignal period, the reaction of the animal pas neprovochenie ). All of these tests can be evaluated at different initial levels of nutritional motivation, which entails the emergence of emotional arousal of the animal.
After a stable strengthening of the conditional skill and a 100% differentiation (not very hungry rabbit - 16-hour starvation), the latent period of the conditional reaction did not exceed 1-1.5 sec, the run-time 1-1.5 sec, the animal clearly pulled out the necessary length of the ring , the meal time did not exceed 25-30 s, the rabbit returned for the barrier only after it had completely eaten food.
The intensity of the waiting reaction was 1-2 points. Separate spontaneous jumps were performed, during which the animal moved around the chamber, sniffing it. Return over the barrier was delayed up to 20–40 s. At the differentiation signal, the rabbit approached the barrier, looked at the signal for a few seconds, then turned away. A one-time non - reinforcement of a properly executed action usually did not cause a vivid “mismatch” reaction. Pulling the ring 2-4 times, the animal quietly turned away from the feeder.