LEARNING MEMORY

DR NILESH KATE
MBBS,MD
ASSOCIATE PROF
ESIC MEDICAL COLLEGE, GULBARGA.
DEPT. OF PHYSIOLOGY
HIGHER
FUNCTIONS OF
BRAIN
LEARNING AND
MEMORY

OBJECTIVES
 LEARNING
 Incidental learning
 Reflex learning
 MEMORY
 Implicit memory
 Explicit memory
 Mechanism of memory
 INTERHEMISPHERIC
TRANSFER OF
LEARNING AND
MEMORY
 HIGHER INTELLECTUL
FUNCTIONS OF
PREFRONTAL CORTEX
 Thought process
 Working memory
 Episodic memory
Saturday, February 20, 2016 HIGHER FUNCTIONS OF BRAIN. 2

LEARNING & MEMORY
 Learning – Neural
mechanism by which
individual changes
behaviour on the basis of
past experience.
 Memory – Acquisition ,
storage & retrieval of
sensory information

LEARNING .
 Reflex learning.
 Associated with
immediate behaviour
change.
 Incidental learning.
 Behaviour change not
immediate
 But person gets
information from
sensory inputs &
develop potential to
behave differently.
Saturday, February 20, 2016 4HIGHER FUNCTIONS OF BRAIN.

REFLEX LEARNING.
 Non- associative .
Person learns about
properties of single
stimulus when
repeatedly exposed to
same stimulus.
 Associative.
Person learns about
relationship between
two stimuli or a
stimulus & behaviour.

NON- ASSOCIATIVE .
 Habituation
Decrease in response
to benign stimulus
when stimulus
presented repeatedly.
 Sensitization.
 Increase in response
to benign stimulus
when stimulus
presented repeatedly.

First time it evokes a novel response (orientation
response or what is it response)
Evokes less & less response when repeated
Subject becomes habituated to the
stimulus & ignores it
Habituation
 If a stimulus is repeated
many times

Habituation
 Example
 New clock in the
room.

Cellular basis of Habituation.
 Given by KANDEL
& his collegue.
 Repeated stimulus.
 Inactivation of Ca
influx at axon endings.
 Neurotransmitter
release at synapses.

Sensitization
 Example
 Spanking.

Cellular basis of Sensitization.
 Given by KANDEL
& his collegue.
 Repeated stimulus.
 neurotransmitter
release at synapses.

 Due to Presynaptic
Facilitation by
third interneuron ---
Facilitatory
neuron.
which releases
SEROTONIN.
Sensitization

Pathway in increased release of
Neurotransmitter.

REFLEX LEARNING.
 Non- associative .
Person learns about
properties of single
stimulus when
repeatedly exposed to
same stimulus.
 Associative.
Person learns about
relationship between
two stimuli or a
stimulus & behaviour.

ASSOCIATIVE LEARNING.
 Classical
conditioning.
 Learning relationship
between two stimuli.
 Type I, Type S,
respondant
conditioning or
Pavlovian
conditioning.
 Operant
conditioning.
between special
behaviour with a
reinforcement event.
 Type II, Type R,
Instrumental or Trial
& error conditioning.

CLASSICAL CONDITIONING.
 Characteristic features.
 Conditioned reflex is Reflex response.
 Acquired by repeatedly pairing given stimulus with
another stimulus which normally produces the response.
 Thus temporal association made between neutral
conditioned stimulus (CS) & unconditioned stimulus.
(US)
 It depends upon formation of new functional connections
in CNS.
 Reinforcement -- CS SHOULD FOLLOWED BY US

CLASSICAL CONDITIONING.

Pre-requisites for development of
conditioned reflex.
 Alertness & good health.
 Timing of CS & US – CS US.
 Duration of CS – Should overlap US.
 Reinforcement. CS US.
 No External Inhibition.
 Type of US
 Sensory / motor
 Pleasant, unpleasant / Neutral.

Physiological basis of conditioned
reflexes.
Formation
of new
connections
in the
Nervous
system

Cellular mechanism of
conditioned reflex.

ASSOCIATIVE LEARNING.
 Classical
conditioning.
between two stimuli.
 Type I, Type S,
respondant
conditioning or
Pavlovian
conditioning.
 Operant
conditioning.
between special
behaviour with a
reinforcement event.
 Type II, Type R,
Instrumental or Trial
& error conditioning.

OPERANT CONDITIONING.
 Reward
conditioning.
Naturally occurring
response is
strengthened by
positive
reinforcement
( reward)
 Adversive
conditioning.
Naturally occurring
response is
Weakened by
Negative
reinforcement
( Punishment)

Experiment to demonstrate
Operant conditioning.

Experiment to demonstrate
Operant conditioning.
 Positive Reinforcement – pressing a lever is
associated with positive reinforcement,
reward i.e. food.
 Negative Reinforcement – pressing a lever
is associated with Negative reinforcement,
punishment i.e. electric shock.

MEMORY.
 Memory –
Acquisition ,
storage &
retrieval of
sensory
information

TYPES OF MEMORY.
 Physiologically on
the basis of how
information is stored
& recalled.
 Implicit memory.
 Explicit memory.
 Depending upon
permanency of
storage.
 Short term.
 Intermediate long
term.
 Long term.

TYPES OF MEMORY.
 Implicit memory.
 Non-declarative /
reflexive memory.
 How to perform
something.
 Not associated with
awareness not involve
processing in
hippocampus.
 Declarative / Reconition
memory
 Factual knowledge of
people, places & things.
 Associated with
awareness ,Involve
processing in
hippocampus.

IMPLICIT MEMORY.
 How to perform
something.
 Does not depend on
conscious process.
 Includes motor skills,
habits, behavioral
reflexes & learning
procedure & rules.
 Unconsciousness &
automatic

Implicit memory – reflexive
learning.

EXPLICIT MEMORY.
 Declarative /
Recognition memory
 Factual knowledge of
people, places & things.
 Associated with awareness
,Involve processing in
hippocampus.

EXPLICIT MEMORY.
 SEMANTIC MEMORY.
 About knowledge of
objects, facts and
concepts.
 Words & their
meanings.
 EPISODIC MEMORY.
 Memory of events &
personal experience.

SEMANTIC MEMORY.
 Storage of semantic
memory
 In distributed fashion in
different association
cortices.
 Visual memory
 Auditory memory
 Somatosensory
memory.
 Alarm clock

Damage to cortical area – loss
of specific information
 Associative Visual
Agnosia – posterior
parietal cortex damage –
can identify but cannot
name the objects.
 Appreciative Visual
Agnosia – posterior
occipital lobe damage –
can name the objects but
cannot draw

EPISODIC MEMORY.
 Storage of Episodic
Memory
 In association area of
prefrontal cortex.
 With other areas of neo-
cortex for collection of
information
 Damage – Source
Amnesia.

MECHANISM OF MEMORY.
 Implicit Memory.
 Habituation
 Sensitization
 Classical conditioning.
(already seen in previous slides)

MECHANISM OF LONG TERM
STORAGE MEMORY.
 Implicit Memory.
 CONSOLIDATION – process by which short
term memory is converted into long term.
 Gene expression
 New protein synthesis.
 Growth

MECHANISM OF MEMORY.
 Short term memory.
 Neural substrate for encoding of memory.
 Intermediate long term.
 Long term.
 Consolidation of memory.
 Storage of memory.

Principles of Memory.
 Encoding.
 Elaboration. (Item specific)
 Organization (Inter-item)
 Storage.
 Time-dependency (Interference)
 Retrieval.
 Cue-dependency.
 Encoding specificity.
 Schematic processing.
 Reconstruction.

Neural substrate for encoding
of memory.

MECHANISM OF INTERMEDIATE
LONG TERM MEMORY
 Intermediate Memory
due to temporary
physical or chemical
change in pre or post
synaptic membrane.
 Still labile until
becomes long term by
process called –
Consolidation.

PHYSIOLOGICAL PROCESS.

MECHAANISM OF LONG TERM
MEMORY
 Consolidation of
Memory
 For mild – 5-10 min
 For strong – 1 or more
hour.
 If this time not given –
retrograde amnesia
 E.g. – Precise time of
sleep

PROCESS OF CONSOLIDATION
 Expression of genes
 Synthesis of new
proteins
 Structural changes.
 Increase in no of vesicle
release sites
 No of vesicles
 No of synaptic terminals
 Change in shape or no of
postsynaptic spines

RETRIEVAL OF MEMORY.
 Working memory.
 Components.
 Attentional control
system.
 Rehearsal system.
 Articulatory loop.
 Visuospatial sketch pad.

Working
memory.

LEARNING & MEMORY
 Interhemispheric transfer of learning &
memory.
 Experiment to demonstrate importance of corpus
callosum for interhemispheric transfer of
information.

APPLIED ASPECT.
 Drugs facilitating
learning & memory.
 Common CNS stimulant
 Caffeine, amphetamine,
Physostigmine, nicotine,
Strychnine
 Mechanism of action.
 By facilitating
consolidation of energy.

AMNESIA.
 Antegrade.
 Inability to establish
new long term
memories
 Mostly in lesions
involving
hippocampus.
 Retrograde –
 Inability to recall past
memories.
 Amnesia greater for
recent past than remote
past.
 Lesions involving
temporal lobe
(Temporal lobe
syndrome)

SENILE DEMENTIA.
 Syndrome in elderly
people characterized by
progressive impairment of
memory & cognitive
capacity.
 Causes –
 Alzheimer’s disease,
Cerebrovascular disease,
Parkinsonism,Lewy body
dementia, Prion disease

Alzheimer’s
disease.
 Senile dementia
 Prototypical
neurodegenerative
disease.

CHARACTERISTIC FEATURES.
 Loss of recent memory.
 Impairment in other
areas of cognition –
language, problem
solving, judgment,
calculation, attention.
 Psychiatric symptoms
 Loss of spatial
orientation.

Higher intellectual functions of
prefrontal association cortex.
 Thought process.
 Working memory & intellectual functions.
 Episodic memory.

CONCEPT OF DOMINANT
HEMISPHERE IN LANGUAGE.
 Interpretive functions
of Wernicke’s area,
Angular gyrus &
Frontal motor speech
area – more developed
in Dominant
hemisphere.

CONCEPT OF DOMINANT
HEMISPHERE IN LANGUAGE.
 95% left hemisphere is dominant.
 Motor area for hand movement is
associate with speech area so right
handedness in 90%.
 Wernicke’s area in Non-dominant
is concerned with emotional
content, intonation of spoken
language, understanding &
interpreting non-verbal, visual &
auditory experiences as
interpretation of Music.

CONCEPT OF CATEGORICAL &
REPRESENTATIONAL HEMISPHERE.
 Functions allotted to
left hemisphere in
right handed person.
 Right hand control.
 Spoken language.
 Written language.
 Mathematical skills.
 Scientific skills.
 Reasoning.
 Functions allotted to right
hemisphere in right
handed person.
 Left hand control.
 Music awareness.
 Three dimensional
awareness.
 Art awareness.
 Insight.
 Imagination.

Thank
You

LEARNING MEMORY

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