Theories of internal inhibition localization
In normal physiology, there are several approaches to explaining where exactly the process of blocking a conditioned reflex arises and develops. Historically, the first was I.P. Pavlov's theory. According to this classical concept, internal inhibition originates and proceeds directly within the brain structures, specifically in the cortical cells that serve as the functional representation of particular conditioned stimuli.
However, accumulated modern data have significantly expanded and refined this understanding. In particular, researchers have paid close attention to the behavior of various components of a complex reflex response: autonomic, secretory, somatic, and motor. It has been found that during active inhibition of a specific response (for example, when conditioned salivation ceases), the autonomic components of the response do not disappear anywhere. Equipment continues to clearly record concomitant changes in the animal's heart rate and respiratory rate.
The phenomenon of schizokinesis
The situation described above, where one part of a complex reflex response is inhibited while another continues to function, has received a special term in physiology — schizokinesis. Literally, this concept translates as "splitting of the response."
The existence of the schizokinesis phenomenon allowed physiologists to draw a crucial theoretical conclusion. It became completely obvious that internal inhibition does not affect or destroy the basic structure of the formed reflex arc itself. The inhibitory process is localized and implemented exclusively on the effector pathways, i.e., at the stage where the final formation of specific executive components of the reflex occurs.
Experimental confirmation: the double-reinforcement experiment
To visually demonstrate the mechanisms of response splitting and prove the effector localization of inhibition, physiologists use a classical methodology with double reinforcement. In this experiment, a laboratory dog is secured in a special apparatus equipped with two independent feeders located on the right and left sides of the animal.
The experiment includes several sequential stages:
- Stage 1 (establishment of the baseline reflex). An auditory stimulus—the tone "A"—is presented to the animal. This sound is always accompanied by food reinforcement delivered strictly from the right feeder. As a result, a complex conditioned reflex response is formed in the dog: upon hearing the tone "A," salivation begins (secretory response), and it makes a targeted movement to the right (motor response).
- Stage 2 (change in signaling significance). A new stimulus is introduced—the tone "F." This sound signals to the dog that food will now appear in the left feeder. The dynamics of acquiring the new skill are quite specific: initially, the animal regularly makes mistakes and heads toward the right feeder out of habit when hearing the tone "F."
- Stage of pronounced inhibition. As the experiment continues, a critical moment arrives. Upon hearing the tone "F," the dog no longer makes erroneous movements to the right, but has not yet learned to consistently go to the left. It remains sitting right in the middle of the apparatus. At the same time, objective recording shows a striking picture:
- Salivation: present in full volume (the conditioned secretory response is preserved, the animal expects food).
- Movement: completely absent (the motor response is inhibited).
Conclusion of the experiment: This experiment brilliantly demonstrates that the inhibition of a conditioned reflex response occurs precisely at the level of the executive components. A classical dissociation (separation) of motor and secretory responses is observed in the apparatus, confirming the preservation of the reflex arc during the selective blocking of the effector pathway.
Briefly: answers to topical questions
How does internal inhibition differ from external (unconditioned) inhibition?
Internal inhibition differs in that it arises within the conditioned reflex arc itself and requires special conditions for its development.
| Characteristic | Internal inhibition | External inhibition |
|---|---|---|
| Localization | Arises within the conditioned reflex arc itself | Opposed to internal inhibition in terms of localization |
| Development | Requires special conditions and special training; is not innate | Not explicitly described in the provided sources |
What are the mandatory conditions for the development of internal inhibition?
The primary and mandatory condition for the formation of internal (conditioned) inhibition is the absence of reinforcement for the conditioned signal.
Since this type of inhibition is not innate, it requires the creation of special conditions and special training (acquisition). At the initial stages, an orienting-investigatory reaction occurs in response to the unreinforced signal, which is subsequently replaced by a negative emotion, making the initial development difficult.
The term "schizokinesis" is easy to remember through the association with splitting. Picture the dog in the apparatus between two feeders at the inhibition stage: saliva is flowing (secretion is active), but the paws are still (motility is blocked) — the response has split.
Class and exam questions
Where is internal inhibition localized according to I.P. Pavlov's theory?
According to I.P. Pavlov's classical theory, this process develops directly in the cortical cells, which represent the conditioned stimuli in the brain.
What is schizokinesis in the context of higher nervous activity?
Schizokinesis is the splitting of a reflex response. During schizokinesis, a specific response (e.g., secretory or motor) is inhibited, while autonomic components (heart rate, respiration) continue to be actively recorded.
Does the structure of the reflex arc break down during internal inhibition?
No, the structure of the arc remains completely intact. Inhibition does not affect the basis of the reflex itself, but is implemented exclusively on the effector pathways of its formation.
What does the double-reinforcement experiment prove?
The experiment proves that inhibition occurs at the level of executive components. It clearly demonstrates the dissociation (splitting) of the animal's motor and secretory responses at the inhibition stage.
What else to study on this topic
- Features of the localization of inhibition in cortical cells according to I.P. Pavlov
- Comparison of autonomic, secretory, and motor components of the reflex
- Dynamics of errors during reflex acquisition at the feeder-switch stage
- Significance of response dissociation for organism adaptation
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