AFFERENT SYNTHESIS

From Big Medical Encyclopedia

AFFERENT SYNTHESIS (afferens bringing; grech, synthesis connection, drawing up) — process of comparison, selection and synthesis numerous and different in functional value of the afferentation caused by various impacts on the organism occurring in c. the N of page, on a basis to-rogo forms the purpose of action.

Ampere-second. according to the theory of functional system of Anokhin — the first, universal, a stage of any purposeful behavioural act (see. Functional systems).

Ampere-second. includes processing of 4 main types of afferent vozbuzhdeniye.

1. Motivational excitement reflects the dominating requirement of an organism, edges arises under the influence of metabolic, hormonal, and at the person — and social factors the Motivation plays a crucial role in formation of the purpose of action (see. Motivations ). Specifically increasing reactivity of cortical neurons with the help approximate and research reaction (see), motivational excitement promotes processing and active selection of the touch information necessary for creation of purposeful behavior.

2. The Obstanovochny afferentation represents impact on an organism of all set of the external factors making a specific situation, against the background of a cut adaptive activity is developed. The Obstanovochny afferentation forms not only constant components of a situation, but also a number of consecutive afferent impacts on an organism. Idiosyncrasy of an obstanovochny afferentation consists that it gives specifics of future behavioural reaction, providing its adaptive value only in this situation.

Most clearly the role of an obstanovochny afferentation is shown in experiences with conditioned reflexes. In these cases the animal answers with conditional defensive reaction in one experimental camera the same conditioned excitator and conditional food — in another (or in the same experimental camera in the morning the animal answers with a feeding response, and in the evening — defensive).

3. The device of memory taking into account motivational excitement and an obstanovochny afferentation gives the chance to an organism to use results of last experience for the decision-making most adequate for achievement of useful effect in this situation.

As a result of interaction various on the functional value of vozbuzhdeniye — the dominating motivation, an obstanovochny afferentation and mechanisms of memory in c. the N of page is created the hidden prestarting integration of vozbuzhdeniye. It defines a form and features of future behavioural act, the push, an incentive, starting afferent excitement is necessary for implementation to-rogo.

4. Starting afferentation. A characteristic type of a starting afferentation is the conditioned excitator. Opening in advance created prestarting integration a vozbuzhdeny, starting incentive quite often loses independent value. Most clearly it is shown in a dynamic stereotype.

Basis of physiological processes of Ampere-second. convergence (convergence) of vozbuzhdeniye from various receptor educations on the same neurons already at the level of subcrustal educations makes: a reticular formation of a trunk of a brain, some kernels of a thalamus, etc. (see. Brain , physiology).

The flows of vozbuzhdeniye ascending from a reticular formation, a hypothalamus and a thalamus have biological specifics. They create broad overlappings of neurons in a cerebral cortex, selectively involve in process those synoptic organizations of neurons which in filo-and ontogenesis were connected with a certain biological state. Each cell of bark assumes a huge number of the impulsation meeting from subcrustal formations and other cells of bark and thus participates in processes of Ampere-second.

Experimental studying of Ampere-second. showed that ability to combine and hold different types of afferent vozbuzhdeniye in synthetic association belongs preferential to neurons of frontal departments of a cerebral cortex.

Ability of nervous cells to assume excitement various touch and in particular biological value is defined, as shown in P. K. Anokhin's laboratory, by specific chemical sensitivity of subsynaptic membranes. It is possible to assume that chemical distinctions of subsynaptic membranes are a starting point for start of chains of enzymatic processes in the cytoplasm of nervous cells.

The specific neurophysiological mechanisms providing afferent synthesis are the corticosubcortical reverberation (circulation) of excitement and centrifugal setup of peripheral receptors allowing to eliminate redundant information.


Bibliography: Anokhin P. K. Physiology and cybernetics, in book: Filosofsk. vopr. cybernetics, under the editorship of V. A. Ilyin, etc., page 262, M., 1961; about N e, Biology and neurophysiology of a conditioned reflex, M., 1968, bibliogr.; it, Methodological value of cybernetic patterns, in book: Materialistich. dialectics and methods of natures. sciences, under the editorship of M. E. Omelyanovsky, page 547, M., 1968; it, Fundamental issues of the general theory of functional systems, M., 1971; it, Systems analysis of integrative activity of neuron, Usp. fiziol, sciences, t. 5, No. 2, page 5, 1974; K. V Pike perches. Biological motivations, M., 1971.

A. I. Shumilina.

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