Main postulates of the theory
The concept is based on several key provisions explaining how goal-directed behavior is formed:
- Ascending influences: subcortical structures exert a specific activating effect on the cerebral cortex.
- Afferent synthesis: the formation of a reaction begins with the gathering of information, where motivation, environmental signals (triggering and situational), and memory play a decisive role.
- Sensory-biological convergence: excitations of different natures (e.g., from sensory organs and biological needs) converge on the same cortical neurons.
- Integration: cortical neurons are able to combine these heterogeneous signals.
- Action result acceptor: the brain creates a special apparatus for predicting and evaluating the future result.
How a conditioned reflex is formed
According to the convergent theory, the process of forming a temporary connection involves several stages of interaction between various excitations on cortical neurons.
- Motivation: motivational centers of the hypothalamus send activating influences to the cortex, forming a subjective feeling (e.g., food need or hunger).
- Interaction: excitation from a neutral stimulus (e.g., a flash of light) meets in the cortex with the pre-existing motivational state.
- Reinforcement and connection: when an unconditioned stimulus (food) is presented after the light, sensory and motivational excitations are specifically directed to the same neurons in the projection zone of the conditioned stimulus. The temporary connection itself is consolidated with the participation of the genetic apparatus of these cells.
Limitations of the classical reflex theory
I.P. Pavlov's classical model was based on the principle of the leading role of external stimuli (the "stimulus-response" scheme) and had a number of methodological limitations. Animals in the experiments were passive (kept in a apparatus), and their behavior was evaluated only by response reactions (motor or autonomic: salivation, changes in pulse and respiration).
This approach ignored the active goal-directed behavior of animals in their natural environment aimed at meeting their needs. The old theory could not explain numerous phenomena:
- Why the conditioned response disappears immediately after feeding (mechanism of satiety).
- How the animal actively searches for stimuli and overcomes obstacles.
- Error correction mechanisms.
- The role of reinforcement if viewed merely as an unconditioned reflex.
- Complex instrumental activity (creation and use of tools by anthropoids).
Also, emotions, motivations, decision-making, dynamic stereotypes, neuroses, as well as play, hunting, and herd behavior do not fit into the structure of a simple reflex arc.
Briefly: answers to topical questions
What cellular and molecular mechanisms ensure the consolidation of the temporary connection with the participation of the genetic apparatus of neurons?
The consolidation of the temporary connection and the formation of long-term memory are ensured by a cascade of biochemical processes involving gene expression and protein synthesis.
- Intracellular signaling — changes in the synapse generate signals that go to the cell nucleus.
- Gene expression — first, "early" genes are activated, followed by genes necessary for the synthesis of new synaptic membrane components (glycoproteins).
- Structural reorganization — synthesized proteins are embedded into membranes, leading to an increase in the area of synaptic contact and the number of dendritic spines.
Transcription and translation processes on ribosomes are critically important for the successful consolidation of engrams.
What is the mechanism of action of the action result acceptor in evaluating behavioral success?
The mechanism of the action result acceptor lies in comparing the model of the expected result with the parameters of the actual result.
- Feedback afferentation — carries information about the achieved useful result and goes to interneurons.
- Comparison — the received information is compared with the predicted model.
- Evaluation and correction — if the obtained parameters do not match the expected ones, a mismatch occurs, causing a negative emotion. This stimulates the organism to overcome obstacles and make corrections to the efferent signal to achieve an accurate result.
What subcortical structures, aside from the hypothalamic centers, exert ascending activating influences on the cortex?
Apart from the hypothalamic centers, the sources specifically indicate the reticular formation of the brainstem.
- The reticular formation is activated by active afferentation from sensory organs.
- It exerts ascending activating influences on the cerebral cortex.
- During inhibition or a decrease in the tone of the reticular formation, its ascending activating influences on the cortex diminish.
How exactly is the result prediction apparatus formed (through which neural connections)?
The result prediction apparatus is formed on the basis of intercalated interneurons through the transmission of copies of efferent commands via collateral connections.
- Collaterals of the pyramidal tract — through them, copies of commands are transmitted to interneurons simultaneously with the sending of impulses to effector organs.
- Cyclic relationships — thanks to them, a model of the expected result is created within the group of intercalated interneurons.
- Ahead-of-time excitation — during subsequent behavior, motivation activates the formed neural ensemble in advance, ensuring foresight.
Class and exam questions
What is convergence in Anokhin's theory?
This is the convergence of various types of excitations (e.g., sensory and motivational) onto the exact same neurons of the cerebral cortex.
Which brain structure is responsible for the formation of motivation?
Motivational centers of the hypothalamus, which send ascending activating influences to the cerebral cortex.
What is the main drawback of the classical reflex approach?
It views behavior as a passive response to external stimuli and ignores the internal need and active goal-directed activity of the organism.
What else to study on this topic
- Mechanisms of afferent synthesis
- Functions of the Action Result Acceptor
- Participation of the neuronal genetic apparatus in the closure of the temporary connection
- Mechanisms of satiety and inhibition of conditioned responses
- Differences between active search and passive responding
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