Transcript Conditioned and unconditioned regulation of human activity

Conditioned and unconditioned
regulation of human activity
Higher and lower activity of nervous
system
 The lower nervous activity is directed to regulation of body
functions and organ systems, unification them to entire
organism. The lower nervous activity is performed due to
congenital forms of behavior. The congenital forms are
unconditioned reflexes, instincts; biological motivations and
emotions.
 At the adult person the lower nervous activity usually is not
arises separately from other forms of behavior. Life training
and purchase of acquiring experience results in
specification and modification of congenital forms of
behavior due to the conditioned-reflex mechanism.
Notion about conditioned reflexes
 Conditioned reflexes are individually acquired system of
adaptive reactions of the person and animals. It arises on
the basis of formation in the central nervous system of
temporary communication between centres, some of which
percept new irritant and other control some unconditioned
reflex. Thus, new irritant form an environment becomes
conditional irritant. It warns person about approach of the
subsequent kinds of activity and prepares him for future
kinds of activity (eating, avoidance of danger and another).
 With the help of the conditioned-reflex mechanism such
function of nervous system as purposeful behavior of the
person in an environment and society, the adaptation to
varied conditions of an environment are carried out. Such
activity of nervous system concerns to the higher nervous
activity.
The mechanism of formation of conditioned reflexes
 The structural basis of the higher nervous activity
is brain cortex and the nearest subcortical centres.
At formation of behavior in the central nervous
system on some time are formed neuronal circuits
of a different degree of complexity. In the
environment all the time new irritants occur.
Therefore in a brain cortex at each moment of time
new combinations of neurons are activated.
 Thus, in the brain cortex and the subcortical
centres there is a mosaic and dynamics of
excitation and braking, due to performance of the
higher nervous activity. Such interactions between
neurons give basis of thinking, emotions and
behavior of the person.
Characteristic of conditional irritants
 For development of a conditioned reflex it is necessary, that any
factor of an environment, which may be perceived by one of
analyzer systems of an organism, occur repeatedly and acted on an
organism of the person or an animal. If at each occurrence this
irritant outstrips a little or takes place simultaneously with
performance of any unconditioned reflex in an organism, probability
of development of a conditioned reflex very high. But for formation of
a conditioned reflex still it is necessary, that the brain cortex be in an
active, awake condition.
 For development of a conditioned reflex the important value has
optimum force of irritant, which may become conditional irritant.
Small force irritant does not cause a sufficient level of activity in
neurons of appropriate analyzer system. In this case the conditioned
reflex is formed slowly. Such conditioned reflex exists the short
period of time and then is fast inhibited.
 In real conditions irritants from the environment do not occur as
isolated factor. There are a set of similar irritants and such irritants,
which operate simultaneously
Nervous processes, which lays in the base of
conditioned reflexes formation
 The opportunity spreading excitation in the central nervous
system is caused by presence in it of numerous branches of
shoots of nervous cells - axons and dendrites. Shoots
connect neurons and the nervous centres in a uniform
network. Strengthening of irritation neurons stimulates
distribution of excitation on nervous circuits. Due to existence
of such communications excitation long time may circulate on
closed neuronal to circuits, till opportunities of synapses to
transfer impulses will be exhausted or there will be a braking
process in any of neurons, so the circuit will be opened.
 The centre of excitation, which arises in a brain cortex under
action of conditional stimulus may be spread on neuronal
circuits in all directions. But if simultaneously in an organism
the unconditioned reflex is carried out, in a zone of cortical
representations of this reflex the prepotent centre varying a
direction spreading of excitation develops. In such a case
distribution of the excitation caused by a conditional irritant,
will be directed aside dominants.
Peculiarities of dominanta
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Dominanta (from Latin dominare - to dominate) - is the centres
of excitation prevailing in the central nervous system, which
change and subordinate to themselves activity of other nervous
centres at present. The principle of a dominant is one of main
principles of activity of the central nervous system. The Russian
scientist O.O. Ukhtomsky was formulated these principles.
The prepotent centre of excitation is characterized by such
properties:
1) Increase of excitability;
2) Stability of excitation;
3) Ability to summarize excitation - to accumulation of excitation
from stranger irritants;
4) Ability to inhibit function of other nervous centres and reflex
reactions;
5) Ability long time to keep excitation after the termination
(ending) of irritation, which has caused it (inertia of a dominant).
Synaptic and membrane hypothesis of conditioned
reflexes formation
 It agrees when giving experimental researches, two neuron
classes take part in formation of conditioned reflexes:
command neurons which realize specific behavioral acts
and modulating neurons, which adjust a condition of
command neurons. Before the first appearance of stimulus
and supporting reflex neurons were mainly monotouch. In
process of the further development of a conditioned reflex
neurons get ability to answer different stimulus, that is
become polytouch. After the conditioned reflex is produced,
again it is observed selective reaction of neurons - they
answer only stimulus, which became conditional irritant.
 The synaptic hypothesis considers that the mechanism of
formation of a conditioned reflex is caused by change of an
overall performance of synapses.
 The membrane hypothesis asserts that in a basis of the
mechanism of formation of a conditioned reflex change of
excitability of postsyneptic membrane lays.
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Classification of conditioned reflexes
I. On a way of formation:
1. Classical conditioned reflexes - are formed in natural
conditions.
2. Tool conditioned reflexes - are developed artificially. More
often they represent purposeful motor reactions. As
supporting stimulus for their development the unconditioned
reflex causing in a laboratory animal feeling of pleasure
(effect of "award") or painful irritant, causing avoidance
reaction usually serves.
II. Under the relation of conditional irritant to unconditional:
1. Natural conditioned reflexes - conditional irritant it is related
to an unconditioned reflex. For example, a smell and how a
food looks have the direct relation to irritation by food of
tongue receptors, which starts unconditional salivatory
discharge reaction.
2. Artificial conditioned reflexes - conditional irritant has no the
direct relation to an unconditioned reflex which serves as a
reinforcement. For example, the bell or a light signal in natural
conditions have no the relation to unconditional salivatory
discharge reflex.
Classification of conditioned reflexes (next)
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III. On biological importance:
1. Food conditioned reflexes - provide getting food and digestion.
2. Sexual conditioned reflexes - provide sexual behavior.
3. Protective conditioned reflexes - provide defensive reactions.
4. Statokinetic conditioned reflexes - provide motor behavioral
reactions and impellent skills.
5. Homeostatic conditioned reflexes - are directed on maintenance
of a constancy of the inner environment of an organism.
III. On a degree of complexity:
1. Conditioned reflexes of the first order - the conditioned reflex is
developed on the basis of a unconditioned reflex.
2. Conditioned reflexes of the second order - the conditioned reflex
is developed on the basis of other conditioned reflex of the first
order.
3. Conditioned reflexes of the third order - the conditioned reflex is
developed on the basis of a conditioned reflex of the second order.
4. Conditioned reflexes of the higher order - are formed only at the
high organization of nervous system. In human formation of
conditioned reflexes of the second - twentieth order is probably.
Process of inhibition in the central
nervous system
 Formation of conditioned reflexes is not
possible without process of inhibition in the
central nervous system.
 Braking of spreading impulses is provided
with various mechanisms and results thus in
various effects. I.P.Pavlov classified braking
processes in the brain cortex as two groups:
external (unconditional) and internal
(conditional).
External (unconditional) inhibition
 The rough reflex causes unconditional braking
because it protects an organism from new unknown
influences of an environment, which possibly may
cause damaging or to warn of danger. At repeated
occurrence of new irritant, which was no dangerous,
its braking effect decreases. Such brake irritants refer
to as time or dying away. There are also constant
brake irritants, which keep brake effect long time.
Pathological processes (for example inflammatory
processes) or strong irritation of proprioreceptors (for
example, overflow of a urine bladder, a rectum) often
have such a value.
 One more kind of external braking is security braking.
It arises at action of very strong irritants or very long
influence of usual force irritants.
Internal (conditional) braking
 This is specific process, which is characteristic for
cerebral cortex. It demands special conditions and
training. The basic condition of development of internal
braking is absence of unconditional reinforcement after
action of conditional irritant when the reflex is already
produced and functions.
 Regular repeated action of conditional irritant without a
reinforcement of it by unconditioned reflex results in
gradual easing a conditioned reflex, and so to its
disappearance, fading away. Such kind of braking refers
as fading away.
 Thanking to fading away braiking the brain is released
from the information which under the present conditions
has lost the value.
Differential braking
 Differential braking develops, if one of two
conditional irritants is always supported with an
unconditioned reflex, and another - is not. In this
case the conditioned reflex on supported irritant is
kept. Another conditional irritant, which is not
supported, every time causes a conditioned reflex
worse while it will not disappear absolutely.
 Differential braking allows specialization of
conditioned reflex and is a basis of the adequate
analysis of subjects and the phenomena of an
environment, and also changes in the inner
environment of an organism.
Conditional brake of existing
reflex
 One of versions of differential braking - a
conditional brake. If to add new irritant to
conditional irritant and to repeat this combination
many times without any reinforcement, new
irritant brake conditioned reflex produced earlier.
In this case conditional irritant loses the alarm
action, and inhibition of conditioned reflex
occurs.
 Conditional brake permits constantly specify
character of conditional reflex reactions for
concrete irritants from an environment.
Late braking
 When the time interval between action of conditional and
unconditional irritant is increased, the conditioned reflex
appears with delay. In performance of a late reflex
distinguish two phases - inactive, when reactions on
conditional irritant is not present, and active, when there
is a reflex reaction. Late braking helps to regulate work
of internal visceral organs (for example, regulation
secretion of the stomach after meal), develop skill to wait
and to keep energy in case of strong irritation.
 Braking in brain cortex is carried out by braking neurons.
Most likely, this function is performed by star cells. It is
established, that on the mechanism of braking in a brain
cortex is caused by postsynaptic hyperpolarizing. It is
caused basically by change of permeability of Clchannels of postsynaptic membrane. The basic
neurotransmitter in braking neurons is gammaaminobatteric acid.
Stages of coditioned reflex
activity
 Stage of generalization of a
conditioned reflex
 Stage of specialization of a conditioned
reflex
 Inhibition of the conditioned reflex
Age peculiarities of inhibition
 Braking of conditioned reflexes is possible since the first
days of life of the child, basically with the help of external
braking. At children of the first year of life both external and
internal braking easily arises. Long action of irritant can
brakes even rough reaction. Immaturity of the brain cortex
neurons in newborn children causes fast development of
braking process.
 Conditional braking in the first years of life of the child is
advanced very poorly. The force of all kinds of internal
braking and speed of braking of conditioned reflexes
increased with age. Children till 4 years of life distinguish
irritants according to one attribute - color or shape usually.
Integrative functions of the brain develop quickly. 5-6 year
children already differentiate irritants according to 2-4
attributes. Ability to allocate the basic essential component
among set of irritants develops later - by 10-17 years. In old
age internal braking is disturbed, that decreases workability
of a person.
Coordination of functions in a brain
cortex
 All kinds of activity of the person are based on coordination
of functions in a brain cortex due to processes of excitation
and braking. In a healthy organism processes of excitation
and braking in the central nervous system are in dynamic
balance.
 Processes of excitation and braking in the central nervous
system are in complex cooperation and influence to each
other. I.P.Pavlov has established such laws of excitation
and braking interaction. Excitation arising in any centre
inhibits other centres. Concentration promotes processes of
differentiation and an induction. Around of the centre of
excitation there are centres of braking, and around of the
centres of braking - the centres of excitation. I.P.Pavlov has
named it as cortical mosaic. But cells of the brain all time
pass from exciting condition in braking and on the contrary.
Cycle of dream and wakefulness
 Processes of excitation and braking in the central nervous
system, as well as other functions of an organism have daily
cycle. The cycle of dream and wakefulness is one of vital
needs of the organism. The basic function of dream is
restoration of physical and mental forces, which allows
maximal adaptation to change of conditions of the external
and internal environment.
 Dream is alternation of different functional conditions of the
brain. During dream brain activity is reconstructed. There is
a consolidation and processing of the information, which has
arrived during wakefulness. In dreaming information moves
from the short-term memory in the long-term. Activity of
neurons in different departments of the brain cortex and
subcortical nerve centres during dream remains practically
same as well as during wakefulness.
Physiological characteristic of
dream
 According to modern representations, dream consists of
two qualitatively various conditions - slow and fast dream.
Slow dream is divided on some stages, according to
changes on electroencephalogram.
 The first stage is characterized by oppression of the basic
alpha-rhythm, which is gradually replaced with low
amplitude waves of different frequency.
 The second stage is characterized by periodic occurrence
of dream spindles.
 The third and fourth stage is characterized by gradual
increase on electroencephalogram of high amplitude slow
deltas-waves. These stages correspond to deep dream.
Nerve substrate of dream
 Numerous brain structures, which take part in the
organization of dream, are located in the brain stem and
were joined in somnolence system. Nucleus in the brain
partition, in hypothalamus, serotoninaergic neurons in
nucleus of a seam and thalamic synchronizing system
concern to these structures.
 Formation of fast dream connects with reticular nucleus of
the midbrain and limbic structures of the brain.
 Reticular inhibitory area is located medially and ventrally in
the medulla. This area can inhibit the reticular facilitory
area of the upper brain stem and thereby decrease activity
in the superior portions in the b5rain as well. One of the
mechanisms for this is to excite serotoninergic neurons ar
crucial points in the brain.
Factors that cause dream
There are four groups of factors which cause dream:
 1) endogenous factors caused by exhaustion and
somnolence substances;
 2) endogenous cyclic processes in an organism;
 3) unconditional reflex irritants as darkness, rest,
position of a body, touch monotony, influence of
temperature, atmospheric pressure;
 4) conditioned reflexes to the certain conditions of
dream, time of day, its duration.