higher functions of brain.learning memory

DR NILESH KATE

MBBS,MDASSOCIATE PROF

ESIC MEDICAL COLLEGE, GULBARGA. DEPT. OF PHYSIOLOGY

HIGHER FUNCTIONS OF

BRAIN.

LEARNING & MEMORY Learning – Neural

mechanism by which individual changes behaviour on the basis of past experience.

Memory – Acquisition , storage & retrieval of sensory information

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 2

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, February 2, 2015 3HIGHER 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.

Monday, February 2, 2015 4HIGHER FUNCTIONS OF BRAIN.

NON- ASSOCIATIVE . Habituation

Decrease in response to benign stimulus when stimulus presented repeatedly.

Sensitization.

Increase in response to benign stimulus when stimulus presented repeatedly.

Monday, February 2, 2015 5HIGHER FUNCTIONS OF BRAIN.

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.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 7

Cellular basis of Habituation.

Given by KANDEL & his collegue.

Repeated stimulus.

Inactivation of Ca influx at axon endings.

neurotransmitter release at synapses.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 8

Cellular basis of Sensitization.

Given by KANDEL & his collegue.

Repeated stimulus.

neurotransmitter release at synapses.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 9

Due to Presynaptic facilitation by third interneuron --- facilitatory neuron.

which releases SEROTONIN.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 10

Sensitization

Pathway in increased release of Neurotransmitter.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 11

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 condioning.

Monday, February 2, 2015 12HIGHER FUNCTIONS OF BRAIN.

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

Monday, February 2, 2015 13HIGHER FUNCTIONS OF BRAIN.

CLASSICAL CONDITIONING.

Monday, February 2, 2015 14HIGHER FUNCTIONS OF BRAIN.

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.

Monday, February 2, 2015 15HIGHER FUNCTIONS OF BRAIN.

Physiological basis of conditioned reflexes.

Monday, February 2, 2015 16HIGHER FUNCTIONS OF BRAIN.

Formation of new connections in the nervous system

Cellular mechanism of conditioned reflex.

Monday, February 2, 2015 17HIGHER FUNCTIONS OF BRAIN.

OPERANT CONDITIONING. Reward

conditioning.

Naturally occurring response is strengthened by positive reinforcement ( reward)

Adversive conditioning.

Naturally occurring response is weakened by negative reinforcement ( punishment)

Monday, February 2, 2015 18HIGHER FUNCTIONS OF BRAIN.

Experiment to demonstrate Operant conditioning.

Monday, February 2, 2015 19HIGHER FUNCTIONS OF BRAIN.

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.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 20

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 21

MEMORY. Memory –

Acquisition , storage & retrieval of sensory information

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 22

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.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 23

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 24

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.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 25

IMPLICIT MEMORY. How to perform

something. Does not depend on

conscious process. Includes motor skills,

habits, behavioural reflexes & learning procedure & rules.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 26

Implicit memory – reflexive learning.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 27

EXPLICIT MEMORY. Declarative / reconition

memory Factual knowledge of

people, places & things. Associated with

awareness ,Involve processing in hippocampus.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 28

EXPLICIT MEMORY. Semantic memory.

About knowledge of objects, facts and concepts.

Words & their meanings.

Episodic memory.

Memory of events & personal experience.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 29

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.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 30

Principles of Memory. Encoding.

Elaboration. (Item specific) Organization (Inter-item)

Storage. Time-dependency (Interference)

Retrieval. Cue-dependency. Encoding specificity. Schematic processing. Reconstruction.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 31

Neural substrate for encoding of memory.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 32

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 33

RETRIEVAL OF MEMORY. Working memory. Components.

Attentional control system.

Rehearsal system. Articulatory loop. Visuospatial sketch pad.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 34

Working memory.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 35

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 36

LEARNING & MEMORY Interhemispheric transfer of learning &

memory. Experiment to demonstrate importance of corpus

callosum for interhemispheric transfer of information.

Monday, February 2, 2015 37HIGHER FUNCTIONS OF BRAIN.

APPLIED ASPECT. Drugs facilitating learning & memory.

Common CNS stimulant. Amnesia.

Antegrade Retrograde.

Alzheimer’s disease. Pathophysiology Characteristic features.

Senile dementia.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 38

Alzheimer’s disease.

Senile dementia Prototypical

neurodegenerative disease.

Monday, February 2, 2015 HIGHER FUNCTIONS OF BRAIN. 39

Higher intellectual functions of prefrontal association cortex.

Thought process. Working memory & intellectual functions. Episodic memory.

Monday, February 2, 2015 40HIGHER FUNCTIONS OF BRAIN.

Monday, February 2, 2015 41HIGHER FUNCTIONS OF BRAIN.

Thank You