Prerequisites and peculiarities of behavior of dogs
The most complex interrelationships of the dog's organism and the conditions of its life are based on the interaction of nervous processes — excitation and inhibition. The method of conditioned reflexes revealed a number of general patterns inherent in the course of these processes in the brain.
The behavior of dogs. Excitation and inhibition are understood as features of the behavior of dogs that arise in the cerebral hemispheres of neurons and lead to the formation of temporary connections or to suppression of already formed connections.
The basis of the development of conditioned reflexes is the pattern of irradiation and the concentration of the two main processes in the brain. This pattern stems from experimental facts and is expressed in real phenomena. As for the internal states, they were represented as the movement of impulses along the brain mass. Hence the concept - the movement of nerve processes.
Both processes should be considered in their indissoluble unity, which ensures a stable balance of the body.If, say, the process of inhibition had disappeared, then an uncontrollable irritable process would have brought the whole organism into an “over-active” state. Following this, there would be a depletion of the nervous system and the death of the dog. Similar phenomena are observed in case of poisoning with narcotic substances that cause excessive arousal in behavior.
When studying conditioned reflexes, we encountered a phenomenon based on the irradiation of arousal. This phenomenon, called generalization, or the generalization of conditioned stimuli, is that in the initial stage of the formation of a temporal association, a conditioned reflex arises not only in response to a certain signal, but also to other stimuli. When developing a reflex, for example, to a certain tone, other tones (higher and lower) are also able to cause a conditional response, which is the weaker, the further the sound is separated by the height of the tone to which the reaction was developed. This relationship between the strength of the conditioned reaction and the distance separating the conditioned stimulus from other stimuli is called the generalization gradient.
The given example refers to receptor or afferent generalization, since many stimuli that do not fall down the receptors cause the same effect. In motor conditioned reflexes, in addition, there is an effector or efferent generalization, when the same stimulus causes various movements. For the first time this phenomenon was encountered in the study of electrical defensive conditioned reflexes in the laboratory of the famous Russian psychiatrist and physiologist V. Bekhterev. Experimenters noticed that at first the dog was whining in response to a conditioned signal, making movements with its paws and torso. Gradually, the motor reaction became less extensive, and finally everything was reduced to the fact that in response to the signal the animal produced a withdrawal only of the limb that was irritated by an electric current.
The phenomenon of efferent generalization was also described by L. Voronin in the study of various motor conditioned reflexes of a dog (jumping through various objects, placing in a certain position, feeding the paw, etc.) in conditions of its free behavior. Efferent generalization is clearly manifested in the extinction of a single movement or in the development of a new one.So, for example, if the paw feeding reflex was fading, then after “unsuccessful” attempts the dog stopped feeding the paw. Instead, it produced another behavioral act, previously developed in this setting.
When a conditioned reflex is formed, a certain stimulus gradually becomes specific and only a certain movement becomes conditioned reflex. Hence, following the phase of afferent generalization, the phase of afferent specialization begins.
The explanation of these phenomena is included in the concept of forming the prerequisites for a temporary connection in dogs. The nerve closure is carried out as a result of counter-radiation of excitation from the source of conditioned excitation (GWD) and the central afferent link of the unconditional center (CETSC) (Figure 6.8).
At the onset of the formation of a temporary connection (b) between temporary cortical conditional (CWV) and efferent links of the unconditioned center (EZBT) of excitation, temporary connections (at-a) are established between foci caused by agents similar to conditioned stimuli (ASn). Therefore, at the beginning of the formation of a conditioned reflex in a dog on a command with the voice “Lie down”, any command (“Sit!”, “Lie down!”, “Stand!”) Can cause a conditioned reflex.The trainer every day repeatedly combines the command with the voice "To lie!" With food, due to which there is a connection in time of two cortical foci of excitation: one caused by the conditioned, the other by an unconditioned stimulus. Then, due to counter-irradiation, excitement from these cortical foci spreads every time along the same path and a neural connection is established between them (b). Temporary connections established between the cortical points of application of various other stimuli arising in this situation (an
The case of irradiation of excitation from one center of the cortex to another was revealed when analyzing the complex behavior of dogs. They had a sharply expressed active-defensive reflex to all outsiders entering the laboratory during the experiment: the dog barked at them and showed them the strongest aggression. When an employee causing aggression replaced the experimenter, to the surprise of everyone, the conditioned stimulus caused salivation of a much larger magnitude than before. Later experiments showed that if a dog developed two reflexes on the basis of two different unconditioned reinforcements - defensive and alimentary, and then raise the tone of the defensive reflex by applying a strong stimulus,then the food conditioned reflex is enhanced.
When the dog got used to the employee who replaced the experimenter and calmed down, the tone of the active-defensive reaction decreased and, accordingly, this led to inhibition of the conditioned food reflex (salivation decreased). It is established that the presence of irradiation and the concentration of excitation and inhibition, when excited, spreads faster than the inhibitory process (their speed of propagation is approximately as 4: 1).
The parameters of the spread of excitation and inhibition from one center of the brain to another should be taken into account when training and assessing the behavior of service dogs.
For example, with the development of malice in a dog, an increase in the excitability of an active defense reaction can be achieved by prior (5–10 s) feeding the dog, before it begins to develop malice.
Electrophysiological studies confirm the patterns of irradiation and concentration of excitation. They show that during the period of generalization of the conditioned salivary reflex, the accompanying changes in bioelectric activity are recorded in many parts of the cortex and subcortex.
The elaboration of a conditioned reflex, especially in the stage of its generalization, finds its direct expression in the distant synchronization of electric rhythms at the points of the cortex associated with the action of conditioned and unconditioned stimuli. These data were confirmed as a result of the use of multiple recording systems with the processing of material on electronic computers.
Irradiation of excitation at the cellular level has been studied in most detail in connection with the revival of the orienting reaction in the initial stages of the development of a reflex. Its expression is the activation reaction. During the activation reaction, the conduction of excitation from the periphery to the cortex increases, and at the same time, the excitability increases (that is, the reaction threshold decreases) in neurons associated with the unconditional reaction. As a result, a wide range of stimuli is able to cause a conditioned-reflex response in dogs.
In the process of strengthening the temporal connection, the neurons of the reticular formation gradually “go out of the game,” and changes in the nature of the responses can only be found in the cells of the unconditional representation of the conditioned reaction.The excitability of these cells is specifically increased relative to the stimuli whose actions were considered to be their activation. In the theory of GNI, this stage is described as the concentration of the process at the centers of the conditioned and unconditioned stimuli.
As already noted, inhibition in the physiology of nervous activity means suppression of the focus of excitation. The subtle neural mechanisms of this process have not been studied enough. Conditioned reflex inhibition is a complex phenomenon that has the same dynamic characteristics as conditioned reflex excitation, i.e., the ability to irradiate and concentrate.
Irradiate all kinds of internal inhibition. The pattern of irradiation of inhibition was found in all analyzers. Further it has appeared, that if strengthening of internal braking promotes its irradiation, weakening interferes with it. On the basis of numerous experiments, it has been established that the inhibitory process, spreading through the cortex from the center of inhibition, captures other points the more strongly the closer these points are to it.
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