higher functions of brain.learning memory
TRANSCRIPT
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
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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.
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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.
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NON- ASSOCIATIVE . Habituation
Decrease in response to benign stimulus when stimulus presented repeatedly.
Sensitization.
Increase in response to benign stimulus when stimulus presented repeatedly.
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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.
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Cellular basis of Habituation.
Given by KANDEL & his collegue.
Repeated stimulus.
Inactivation of Ca influx at axon endings.
neurotransmitter release at synapses.
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Cellular basis of Sensitization.
Given by KANDEL & his collegue.
Repeated stimulus.
neurotransmitter release at synapses.
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Due to Presynaptic facilitation by third interneuron --- facilitatory neuron.
which releases SEROTONIN.
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Sensitization
Pathway in increased release of Neurotransmitter.
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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.
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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
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CLASSICAL CONDITIONING.
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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.
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Physiological basis of conditioned reflexes.
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Formation of new connections in the nervous system
Cellular mechanism of conditioned reflex.
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OPERANT CONDITIONING. Reward
conditioning.
Naturally occurring response is strengthened by positive reinforcement ( reward)
Adversive conditioning.
Naturally occurring response is weakened by negative reinforcement ( punishment)
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Experiment to demonstrate Operant conditioning.
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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.
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MEMORY. Memory –
Acquisition , storage & retrieval of sensory information
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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.
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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.
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IMPLICIT MEMORY. How to perform
something. Does not depend on
conscious process. Includes motor skills,
habits, behavioural reflexes & learning procedure & rules.
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Implicit memory – reflexive learning.
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EXPLICIT MEMORY. Declarative / reconition
memory Factual knowledge of
people, places & things. Associated with
awareness ,Involve processing in hippocampus.
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EXPLICIT MEMORY. Semantic memory.
About knowledge of objects, facts and concepts.
Words & their meanings.
Episodic memory.
Memory of events & personal experience.
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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.
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Principles of Memory. Encoding.
Elaboration. (Item specific) Organization (Inter-item)
Storage. Time-dependency (Interference)
Retrieval. Cue-dependency. Encoding specificity. Schematic processing. Reconstruction.
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Neural substrate for encoding of memory.
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RETRIEVAL OF MEMORY. Working memory. Components.
Attentional control system.
Rehearsal system. Articulatory loop. Visuospatial sketch pad.
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Working memory.
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LEARNING & MEMORY Interhemispheric transfer of learning &
memory. Experiment to demonstrate importance of corpus
callosum for interhemispheric transfer of information.
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APPLIED ASPECT. Drugs facilitating learning & memory.
Common CNS stimulant. Amnesia.
Antegrade Retrograde.
Alzheimer’s disease. Pathophysiology Characteristic features.
Senile dementia.
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Alzheimer’s disease.
Senile dementia Prototypical
neurodegenerative disease.
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Higher intellectual functions of prefrontal association cortex.
Thought process. Working memory & intellectual functions. Episodic memory.
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Thank You