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biology

Conditioned reflexes

1.

PowerPoint® Lecture Slides
prepared by
Kureysh M. Khamchiyev,
The Dep. of Normal
Physiology, AMU
CHAPTER
1
Conditioned
reflexes
© 2020 Kureysh M. Khamchiyev, AMU.

2.

Chapter 9 Learning Outcomes
1.Physiological basis of behaviour.
2.Congenital (unconditioned reflex) behavior.
3.Acquired (conditional reflex) behaviors.
© Kureysh Khamchiyev

3.

Behavior
• It’s a complex of movements enabling
interaction with the
external environment;
• Accompanied by vegetative reactions
© Kureysh Khamchiyev

Higher nervous activity
• Human behavior in the external environment
• Human adjustment to the changed conditions of the
external environment
• Structures – cortex & sub-cortical structures, sub-cortical
ganglia
• Reflexes – the most complex
© Kureysh Khamchiyev

5.

History of the subject
R. Decart (1596-1650) – reflex arch
І. Sechenov (1829-1905) – the monograph
«Reflexes of the Brain» - 1863
© Kureysh Khamchiyev

6.

Forms of behavior
Inborn – unconditioned reflexes UCR
Acquired –conditioned reflexes
CR
Pavlov and Classical Conditioning
Ivan Pavlov was a physiologist who won a Nobel Prize for his
research on digestion.
His original description of classical conditioning was a byproduct of this research.
He did not set out to discover classical conditioning.
© Kureysh Khamchiyev

7.

Unconditioned reflexes
Is species specified reaction of the body, performed on the basis of
inborn nervous connections, i.е. reflecting phylogenetic adjustment of
species to the environment of their inhabitant.
• They are inborn ones
• They are phylogenetically old, that means they were formed in
course of
phylogenesis
• They are based on certain anatomic structures (segments of
spinal cord or brain stem)
• They exist even without brain cortex influence
• They are inherited They can be regulated by brain cortex
• They are basis for the conditioned reflexes
© Kureysh Khamchiyev

8.

Unconditioned reflexes are divided into:
• Superficial and deep Simple and complex
• Interoceptive (from mucouse membrane of internal organs – for
example urination in case of internal sphincter irritation)
• Proprioceptive (stretch, periosteal,
joint)
• Exteroceptive
(dermal,frommucouse membrane)
© Kureysh Khamchiyev

9.

Conditioned reflexes
Is an individually acquired compensatory reactions, which occur on the
basis of temporal connection in CNS between the centers of conditioned &
unconditioned reflexes
• They are the result of the individual
experience and are formed during
ontogenesis
• They are unstable, that means they need
constant support
• They aren’t based on certain anatomic structures
• They are fixed in brain cortex
• There are such conditioned reflexes as speaking,
writing, reading, calculation, practice
© Kureysh Khamchiyev

10.

Condition of forming of conditioned reflexes
Dominanta - is the centers of excitation prevailing in the central nervous
system, which change and subordinate to themselves activity of other
nervous centers at present.
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 centers and reflex reactions;
5) Ability long time to keep excitation after the termination (ending) of
irritation,
which has caused it (inertia of a dominant).
© Kureysh Khamchiyev

11.

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.
II. Under the relation of conditional irritant to
unconditional:
1. Natural conditioned reflexes
2. Artificial conditioned
III. On biological importance:
1. Food conditioned reflexes
2. Sexual conditioned reflexes
3. Protective conditioned
reflexes
4.Statokinetic conditioned
reflexes
5.Homeostatic conditioned
reflexes
© Kureysh Khamchiyev
IV. On a degree of complexity:
1.Conditioned reflexes of the first order
2.Conditioned reflexes of the second
3.Conditioned reflexes of the third order
4.Conditioned reflexes of the higher
order

12.

Terminolo
gy
Unconditioned Stimulus (UCS) An event that consistently
and
automatically elicits an unconditioned response.
Unconditioned Response (UCR) An action that the
unconditioned stimulus automatically elicits.
Conditioned Stimulus (CS) Formerly the neutral stimulus,
having been paired with the unconditioned stimulus, elicits
the same
response. That response depends upon its
consistent pairing with the UCR.
Conditioned Response (CR) The response elicited by the
conditioned stimulus due to the training. Usually it closely
© Kupunyak
resembles the UCR.
N.I.
© Kureysh Khamchiyev

13.

Regularity of forming and manifestation of
conditioned reflexes
factor of an environment
repeatedly and acted on an organism
brain cortex be in an active
© Kureysh Khamchiyev

14.

Mechanisms of forming of conditioned reflexes
In a classical conditioning experiment, Pavlov trained a dog to associate a
ringing bell with food. Afterward, when the dog heard the bell, it would begin
to salivate even when no food was present.
© Kureysh Khamchiyev

15.

Classical Conditioning
Classical conditioning: acquiring a new response (the
conditioned response) to a previously neutral stimulus (the
conditioned stimulus) that reliably signals the arrival of an
unconditioned stimulus.
Ivan Pavlov:
Russian physiologist who
initially was studying
digestion;
first identified mechanisms
of classical conditioning
© Kureysh Khamchiyev

16.

Phases of classical conditioning:
Classical conditioning proceeds throogh several phases,
depending on the time of presentation of the two stimuli.
• If the conditioned stimulus regularly precedes
unconditioned stimulus, acquisition occurs.
• If
the conditioned stimulus
extinction occurs.
is
the
presented by
itself,
• A pause after extinction yields a brief spontaneous recovery.
© Kureysh Khamchiyev

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18.

19.

Principles, continued
Stimulus Generalization: A tendency to respond to stimuli
that are similar, but not identical, to a conditioned stimulus
(e.g., responding to a buzzer or a hammer banging when
the conditioning stimulus was a bell)
Stimulus Discrimination: The ability to respond differently
to various stimuli (e.g., Rudy will respond differently to
various bells [alarms, school, timer])
© Kureysh Khamchiyev

20.

Operant Conditioning (Instrumental Learning)
Operant Conditioning: Learning based on the consequences
of responding; we associate responses with their
consequences
Operant Reinforcer: Any event that follows a response and
changes its likelihood of recurring
Skinner Box
(conditioning
chamber)
Apparatus designed to
study operant conditioning
in animals
© Kureysh Khamchiyev

21.

Timing of Reinforcement
Operant reinforcement most effective when given immediately after a
correct response
Effectiveness of reinforcement is inversely related to time elapsed after
correct response occurs
© Kureysh Khamchiyev

22.

Types of Reinforcers
Primary Reinforcer: Unlearned and natural; satisfies biological needs (e.g.,
food, water, sex)
Secondary Reinforcer: Learned reinforcer (e.g., money, grades, approval,
praise)
Token Reinforcer: Tangible secondary reinforcer (e.g., money, gold stars,
poker chips)
Social Reinforcer: Provided by other people (e.g., learned desires for
attention and approval)
Continuous Reinforcement: A reinforcer follows every correct response
Partial Reinforcement: Reinforcers do NOT follow every response
Partial Reinforcement Effect: Responses acquired with partial reinforcement
are very resistant to extinction
© Kureysh Khamchiyev

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24.

25.

Differences of conditioned and unconditioned reflexes
Property
Unconditioned reflexes
Conditioned reflexes
Irritant
Direct adequate irritant
Receptive field
Is precisely determined
Direct irritants and their
traces
Is not present a certain
receptive field
Formation and
reaction
Under the genetic program
Terms of
occurrence of a
reflex
The central part of
a reflex arch
Specific specificity
Physiological
importance
© Kureysh Khamchiyev
On action of special
conditions of the external
and internal environment
After birth, in process of
Precisely are not
determined
maturing nervous and
endocrine system
The spinal cord, a brain stem,
The brain cortex and
cortical representation of an UR
subcortical nucleus
Is expressed
Not expressed
Provide a survival of a species Provide behavior and the
higher nervous activity

26.

Inhibition of conditioned reflexes
Conception of inhibition
Formation of conditioned reflexes is not possible without
process of inhibition in the central nervous system.
• Unconditioned - external
• Conditioned - internal
• Transmarginal
Inhibition protects the body from excessive biologically
non-grounded reactions.
It’s a complex process of interaction of elementary
reactions of excitation (EPSP) & inhibition (IPSP) on the
membranes of the neurons
© Kureysh Khamchiyev

27.

Unconditioned (external) – occurs due to the
stimuli arousing new reflex reaction
Extinguishing inhibition – based on orientation reflex (any inhibitory factor).
Constant inhibition – any factor of biological importance, which doesn’t
cause
adaptation (pain).
Characteristic of conditional inhibition
This is specific process, which is characteristic for cerebral cortex. It
demands
special conditions and training.
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.
© Kureysh Khamchiyev

28.

Inhibition of conditioned reflexes
• Inhibition of conditioned reflexes
Unconditioned - external
• Conditioned - internal
• Transmarginal
© Kureysh Khamchiyev

29.

30.

Inhibition protects the body from excessive
biologically non-grounded reactions
It’s a complex process of interaction of elementary reactions of
excitation (EPSP) & inhibition (IPSP) on the membranes of the
neurons
Unconditioned (external) – occurs due to the stimuli
arousing new reflex reaction
Extinguishing inhibition – based on orientation reflex (any
inhibitory
factor)
Constant inhibition – any factor of biological importance, which
doesn’t cause adaptation (pain)
© Kureysh Khamchiyev

31.

Indifferent irritating factor
Of no biological importance
First causes excitation – orientation
reflex «What is it?» reflex
Conditioned
(internal)
Extinction
Differentiation of
conditioned stimulus
Conditioned inhibition
Delayed conditioned
reflexes
© Kureysh Khamchiyev
Extinction
•Develops when conditioned signal isn’t
reinforced by an unconditioned stimulus.
•Multiply repetition is required.
•On
the
reestablishment
of
the
reinforcement the reflex can be restored

32.

Differentiation of conditioned stimuli
One conditioned signal (that is reinforced) is chosen
out of many similar
900 Hz
1000 Hz
1100 Hz
food
Saliva secretion
© Kureysh Khamchiyev
Saliva secretion
Saliva secretion

33.

Conditioned inhibitor
• A type of differentiation
flash
sound
Conditioned
inhibitor
Saliva secretion
© Kureysh Khamchiyev
Saliva secretion
flash

34.

Transmarginal inhibition
Caused by:
Suprathreshold stimuli
Weak long-lasting
stimuli
Overexcitation of CNS
Defense mechanism
There are three stages passed through for state of TMI to be reached.
• equivalent phase: when the response matches the stimuli, which is
considered the normal baseline behavior.
• paradoxical phase: associated with quantity reversal, occurs when small
stimuli receive major responses and major stimuli elicit small responses.
• ultra-paradoxical: the final stage, associated with quality reversal in
which
negative stimulation results in positive responses and vice versa
© Kureysh Khamchiyev

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