Clm 18 april 2016

1. Conditioning, learning and
memory
Dr. Madanmohan. MD, DSc, FIA
Professor & Head, Department of Physiology
Mahatma Gandhi Medical College & Research Institute

2. Learning objectives
1. Define the terms conditioning, learning and
memory.
2. Give the differences between classical and
instrumental conditioning.
3. Describe the physiological mechanisms
involved in learning and memory.
4. Describe the types of memory.
5. Name the conditions that interfere with
consolidation of memory.
6. Give a brief description of senile dementia
and Alzheimer’s disease.

3. Conditioning: a learned response to a stimulus
that previously elicited little/no response.
Conditioned / adapted / accustomed.
Learning: ability to alter behavior /performance
as a result of experience.
Memory: ability to register, store and recall
ideas / images.

4. Conditioning
Conditioned reflex

5. Conditioned reflex:
A reflex response to a stimulus that previously
elicited little / no response
Conditioned response:
adapted, circumstanced, accustomed, different
Example: Going to class, temple festival, picnic.

6. Type I:
Classical conditioning of Pavlov.
Temporal pairing.
Type II:
Instrumental or operant conditioning.
Skinner (1904 – 1990). Response is “elicited”.

7. Classical (Pavlovian) conditioning
Food  salivation Bell no salivation
(US) (UR)
Bell  food  salivation ( Repeat / temporal pairing )
Bell x  salivation
(CS) (CR)
Condtioned reflexes of higher order

8. Examples
UR CR
• Food  saliva Licking, chewing
• CV (visceral) Bio–feedback
• Foot shock (somatic)
• Sexual reflexes Sexual
behaviour

9. Differences
UR: CR:
• Inborn Acquired
• Stable Unstable
• Subcortical Cortical
• All members of species Individual

10. Physiological basis
• Pairing/temporal association of 2 stimuli.
• Establishment of functional connections/
synapses.
• Summation of excitation & synaptic
facilitation.
• Protein synthesis.

11. Physiological significance
1. Habits.
2. Training, sports, skill.
3. Conditioned response to time.
4. Biofeedback: control of BP (yoga).
Adaptation/orientation to time/place/environment

12. Characteristics of conditioned response
1. Specificity:
2. Reinforcement:
Positive R: Pleasant stimulus/sti. of reward
area.
Negative R: Unpleasant reinforcement like
painful shock.
3. Inhibition:
Internal (extinction): CR not re-inforced and
response decreases.
External : CR abolished if there is disturbing
external stimulation after CS

13. Learning

14. Learning
Definition: ability to alter behavior or
performance as a result of experience.
Acquisition of knowledge, skill, attitude,
behavior.
Learning: acquisition. Memory: storage
Memory is essential for learning and the
two are closely linked.

15. Mechanism of learning
(physiological basis)
• Cellular
• Synaptic
• Cortical

16. Cellular level
Rudimentary/no nervous system: vertebrates, unicellular
Simple learning behavior in flatworm:
shock curling
(UR)
Light shock curling
Light curling
(CR)

17. Synaptic level (subcortical)
Habituation/inhibition:
Loud sound startle.
Startle becomes less with repeated stimulation.
Repeated sti Ca++ transmitter.
(boring/neutral)
Learns to ignore:
e.g. mother & baby sleeping on railway platform.
Gradual decrease in response with repeated
non-noxious stimulus.. Is stimulus-specific

18. Facilitation or sensitization:
Repeated sti. Ca++ transmitter
(strong/noxious)
Baby’s faint cry.
Resident doctor on duty.
Increased response to repeated/strong/noxious stimulus.

19. Facilitation & inhibition modify stereotyped
reflexes and responses
learning experiences.
Noxious stimuli increase organism’s
responsiveness to other neutral stimuli.

20. Cortical level
• Learning is more complex.
• Learning makes cortex thicker.
• Formation of new (functional) synapses.
• Intercortical transfer of memory through
corpus callosum and lower levels.

21. • Conditioning is associative learning.
• Habituation and facilitation are
non-associative learning.

22. Memory

23. Memory
Definition: ability to register, store and recall
ideas, images.
Learning Memory.
(acquisition) (retaining)
The two are closely linked & difficult to dissociate.
without memory, no learning.
New learning increases horizon of memory.

24. Performance
Motivation
Interest attention learning
memory intelligence prajna

25. Memory: two types
1. Declarative (explicit): stated, unequivocal.
Conscious recall, recall a trip last wk.
2. Non-declarative (implicit): reflexive, understood.
Unconscious, automatic habit /skill
e.g., ride a bike.

26. Memory: types
Sensory memory or immediate memory.
Primary memory or short-term memory
Secondary memory or long-term memory

27. Declarative memory
1. Short term memory: a few sec to a few min.
Visual (after image), auditory (cough).
Remember a telephone number.
2. Long term/permanent memory: months-years
Recall your school function.
Consolidated, robust.

28. Mechanism of memory
Conditioning and learning memory.
Establishment in two stages.

29. Short term memory
1st stage, initial, reverberating circuit.
Sensory information stored in the circuit.
Modulation of synaptic transmission by
modification of ion channels.
Vulnerable / fragile. Retrieved or destroyed.

30. Long-term memory
(consolidation of memory)
• Reverberating circuits are long/strong enough.
• Synthesis of proteins/neurotransmitters.
• Formation of new (functional) synapses.
• Structural changes in pre /post synapse.
• Facilitation of synaptic transmission.
Encoding is impaired by: head trauma, anesthesia,
hyperthermia, hypothermia, puromycin, ECT …..

31. Areas of brain
Widespread areas (holographic theory).
Categorical (left): logical, learning.
Representational (right): non–verbal, color.
Association areas: Wernicke’s, temporal, frontal.

32. Memory is impaired by
1. Hypoxia
2. Hypothermia
3. Insulin coma
4. General anesthesia
5. Head trauma, brain disease
6. Local chemicals: xylocaine, puromycin
7. Convulsions: high temperature, hyperthemia,
epilepsy, ECT, metrozol

33. Disorders of memory
Dementia: defect in learning, memory and
other intellectual functions.
Elderly (senile): >70 y: ~10%, >85 y: 20-50%
Organic brain disease, psychiatric, toxins,
vitamin B deficiency, disinterested & depressed.
Alzheimer’s disease: premature and progressive
aging and degeneration of brain.
Degeneration of cholinergic neurons,
cerebral atrophy.

34. Anterograde amnesia: unable to form new,
long- term memory.
Retrograde amnesia: unable to recall past
memory.

35. Drugs that facilitate memory
CNS stimulants: caffeine, nicotine, amphetamine.
Ayurvedic herbs: brahmi, mandukaparni.
Mechanism: Increase in excitability,
reverberation, consolidation.

36. Summary
• Conditioning
• Learning
• Memory