Situational and triggering afferentation
These two types of afferentation are responsible for the preparation and start of any bodily action.
Situational afferentation Plays a leading role in the formation of the afferent synthesis stage. Its essence lies in the fact that it is composed of the impact on the organism of the absolute totality of external factors. These factors constitute the specific environment, that is, a kind of background against which the future behavioral act originates and forms. In humans, situational afferentation has a characteristic feature: numerous social factors act as situational stimuli (living conditions, cultural environment, moral norms, and others).
Triggering afferentation Represents afferent excitations that arise from exposure to specific stimuli capable of directly unfolding (i.e., triggering) the behavioral act. If situational afferentation prepares the ground, the triggering one acts as a trigger. Various conditioned stimuli, as well as the factor of time, most often serve as triggering stimuli.
Feedback afferentation and its functions
Feedback afferentation is a fundamental mechanism informing the organism about the results of a performed action. It is absolutely essential for the implementation of any behavioral act, as it allows the brain to evaluate the success of task execution and timely correct emerging errors to achieve a useful adaptive result.
Key functions:
- Brings current information about a need that has arisen in the body to the brain structures.
- Signals the successful achievement of the results of goal-directed behavior.
Mechanism of action in functional systems: Feedback is carried out in the form of continuous nerve impulses coming from interoreceptors, as well as through humoral influences directly on the centers of the nervous system. It constantly signals the degree of achievement of useful results, in particular, how well the optimal level of the body's internal environment parameters is ensured.
Example of implementation (the act of drinking tea):
- Motivation: an intention arises based on metabolism.
- Action: the hand begins to move toward the glass.
- Sensory control: a whole complex of excitations (tactile, temperature, weight, and visual signals) is summed up. Their function is to confirm the conformity of the current result to the initial intention.
- Proprioceptive regulation: continuous signaling from muscles ensures the correct distribution of tone and spatial position of the hand relative to the target.
Types of feedback afferentation
Feedback afferentation arising during any motor act is strictly divided into two categories.
1. Guiding afferentation Its source is predominantly impulses coming from muscle proprioceptors. The main function of guiding afferentation is the regulation of the movement execution process itself in real time.
2. Resultative afferentation By its characteristic, it is always complex (multimodality). Its source is powerful flows from photoreceptors, as well as tactile, gustatory, auditory, and other receptors. Resultative afferentation is subdivided into:
- Stage-by-stage: responsible for strict control of intermediate actions.
- Sanctioning: arises only when the final required result is achieved. It is this type of feedback that consolidates the successful integration of actions (the system quantum of behavior). A classic example of sanctioning afferentation is the physiological state transition from "wanting to drink" to "quenched thirst".
Briefly: answers to topical questions
What components make up the stage of afferent synthesis?
The stage of afferent synthesis consists of the integration of four main components.
- Dominant motivation — the leading energy component that determines the goal of behavior and is built on the basis of various metabolic needs.
- Situational afferentation — information about the totality of environmental factors and the conditions in which the organism is located.
- Memory — the use of past experience associated with the satisfaction of this motivation.
- Triggering afferentation — a specific stimulus that directly unfolds the behavioral reaction at the given moment.
In which apparatus of the functional system does the evaluation of feedback afferentation and the comparison of the result take place?
The evaluation of feedback afferentation and the comparison of the result take place in the action result acceptor (ARA).
The basis of this apparatus is formed by intercalated interneurons of various parts of the brain. The ARA unit carries out the comparison process: comparing the predicted model of the future result (which embeds the "due" parameters) with the actually achieved parameters, information about which comes from receptors in the form of feedback afferentation. If the forecast matches reality, the action stops. In case of a mismatch, a discrepancy arises, and appropriate corrections are made to the action program.
You can remember the types of afferentation by the abbreviation SIT: Situational (creates background), Initiating/Triggering (gives start), Tracking/Feedback (evaluates outcome).
Class and exam questions
What is the difference between triggering and situational afferentation?
Situational afferentation creates the background and the set of conditions for behavior (e.g., social factors), while triggering is a specific stimulus (conditioned stimulus or time) that directly unfolds and starts the action itself.
What is sanctioning afferentation?
This is a type of resultative feedback afferentation that arises exclusively when the final required result is achieved. It consolidates the successful system quantum of behavior (e.g., the feeling of quenching thirst).
Which receptors provide guiding feedback afferentation?
Guiding feedback afferentation is predominantly provided by impulses from muscle proprioceptors, which allows for the regulation of the movement execution process itself.
What else to study on this topic
- The stage of afferent synthesis in the functional system
- The role of humoral influences in feedback afferentation
- The concept of the system quantum of behavior
- Interoreception and control of the internal environment
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