LEARNING MEMORY

DR NILESH KATE

MBBS,MD

ASSOCIATE PROF

ESIC MEDICAL COLLEGE, GULBARGA.

DEPT. OF PHYSIOLOGY

HIGHER FUNCTIONS OF

BRAINLEARNING 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

Monday, May 1, 2023 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.

Monday, May 1, 2023 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.

Learning relationship 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. Learning relationship

between two stimuli. Type I, Type S,

respondant conditioning or Pavlovian conditioning.

Operant conditioning.

Learning relationship 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.

Explicit memory. 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. Explicit 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


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LEARNING MEMORY