Upload
nileshkate79
View
966
Download
0
Embed Size (px)
Citation preview
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 3
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.
Monday, May 1, 2023 5HIGHER 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, May 1, 2023 6HIGHER 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, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 8
Cellular basis of Habituation.
Given by KANDEL & his collegue.
Repeated stimulus.
Inactivation of Ca influx at axon endings.
Neurotransmitter release at synapses.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 9
Sensitization Example Spanking.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 10
Cellular basis of Sensitization.
Given by KANDEL & his collegue.
Repeated stimulus.
neurotransmitter release at synapses.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 11
Due to Presynaptic Facilitation by third interneuron --- Facilitatory neuron.
which releases SEROTONIN.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 12
Sensitization
Pathway in increased release of Neurotransmitter.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 13
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, May 1, 2023 14HIGHER FUNCTIONS OF BRAIN.
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.
Monday, May 1, 2023 15HIGHER 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, May 1, 2023 16HIGHER FUNCTIONS OF BRAIN.
CLASSICAL CONDITIONING.
Monday, May 1, 2023 17HIGHER 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, May 1, 2023 18HIGHER FUNCTIONS OF BRAIN.
Physiological basis of conditioned reflexes.
Monday, May 1, 2023 19HIGHER FUNCTIONS OF BRAIN.
Formation of new connections in the Nervous system
Cellular mechanism of conditioned reflex.
Monday, May 1, 2023 20HIGHER FUNCTIONS OF BRAIN.
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.
Monday, May 1, 2023 21HIGHER 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, May 1, 2023 22HIGHER FUNCTIONS OF BRAIN.
Experiment to demonstrate Operant conditioning.
Monday, May 1, 2023 23HIGHER 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, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 24
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 25
MEMORY. Memory –
Acquisition , storage & retrieval of sensory information
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 26
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, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 27
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 28
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, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 29
IMPLICIT MEMORY. How to perform
something. Does not depend on
conscious process. Includes motor skills,
habits, behavioral reflexes & learning procedure & rules.
Unconsciousness & automatic
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 30
Implicit memory – reflexive learning.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 31
EXPLICIT MEMORY. Declarative /
Recognition memory Factual knowledge of
people, places & things. Associated with awareness
,Involve processing in hippocampus.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 32
EXPLICIT MEMORY. SEMANTIC MEMORY.
About knowledge of objects, facts and concepts.
Words & their meanings.
EPISODIC MEMORY.
Memory of events & personal experience.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 33
SEMANTIC MEMORY. Storage of semantic
memory In distributed fashion in
different association cortices.
Visual memory Auditory memory Somatosensory
memory.
Alarm clock
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 34
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 35
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.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 36
MECHANISM OF MEMORY. Implicit Memory.
Habituation Sensitization Classical conditioning.
(already seen in previous slides)
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 37
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 38
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, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 39
Principles of Memory. Encoding.
Elaboration. (Item specific) Organization (Inter-item)
Storage. Time-dependency (Interference)
Retrieval. Cue-dependency. Encoding specificity. Schematic processing. Reconstruction.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 40
Neural substrate for encoding of memory.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 41
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 42
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.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 43
PHYSIOLOGICAL PROCESS.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 44
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 45
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 46
RETRIEVAL OF MEMORY. Working memory. Components.
Attentional control system.
Rehearsal system. Articulatory loop. Visuospatial sketch pad.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 47
Working memory.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 48
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 49
LEARNING & MEMORY Interhemispheric transfer of learning &
memory. Experiment to demonstrate importance of corpus
callosum for interhemispheric transfer of information.
Monday, May 1, 2023 50HIGHER FUNCTIONS OF BRAIN.
APPLIED ASPECT. Drugs facilitating
learning & memory. Common CNS stimulant Caffeine, amphetamine,
Physostigmine, nicotine, Strychnine
Mechanism of action. By facilitating
consolidation of energy.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 51
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)
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 52
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
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 53
Alzheimer’s disease.
Senile dementia Prototypical
neurodegenerative disease.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 54
CHARACTERISTIC FEATURES. Loss of recent memory. Impairment in other
areas of cognition – language, problem solving, judgment, calculation, attention.
Psychiatric symptoms Loss of spatial
orientation.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 55
Higher intellectual functions of prefrontal association cortex.
Thought process. Working memory & intellectual functions. Episodic memory.
Monday, May 1, 2023 56HIGHER FUNCTIONS OF BRAIN.
CONCEPT OF DOMINANT HEMISPHERE IN LANGUAGE.
Interpretive functions of Wernicke’s area, Angular gyrus & Frontal motor speech area – more developed in Dominant hemisphere.
Monday, May 1, 2023 57HIGHER FUNCTIONS OF BRAIN.
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.
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 58
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.
Monday, May 1, 2023 59HIGHER FUNCTIONS OF BRAIN.
Monday, May 1, 2023 60HIGHER FUNCTIONS OF BRAIN.
Thank You
Monday, May 1, 2023 HIGHER FUNCTIONS OF BRAIN. 61