4. Learning & Memory
Learning is acquiring new, or modifying existing, knowledge,
behaviors, skills & values.
A characteristic of animals and particularly of humans is the
ability to alter behavior on the basis of experience.
Learning is acquisition of the information that makes this possible
& Memory is the retention and storage of that information.
Memory is the processes by which information is encoded, stored
& retrieved.
6. Habituation
Habituation is an example of non-associative
learning in which there is a progressive
diminution of behavioral response with
repetative stimulus.
Molecular mechanism – Decrease in NT release
at synapse due to inactivation of Calcium
influx at the axonal endings ( channels
inactivation )
7. Sensitization
Sensitization is opposite to habituation in which
the progressive amplification of a response
follows repeated administrations of a
stimulus.
Molecular mechanism – Increased release of
NT due to 3rd facilitatory interneuron –
presynaptic fascilitation – release of serotonin
– 2 receptors
9. Serotonin
1st receptor – Gs – AC – cAMP – PKA – decrease
potassium current – prolongs AP – increased
calcium influx – increased NT release
Vesicles mobilisation – exocytosis
Opens L type of calcium channels
2nd receptor – Go – PLC – DAG – PKC - Vesicles
mobilisation & Opens L type of calcium channels
11. Associative learning
Associative learning is the process by
which an association between two
stimuli or a behavior and a stimulus is
learned.
Classical – 2 stimuli
Operant – stimuli & behaviour
12. Classical conditioning
Classical conditioning involves repeatedly pairing an
unconditioned stimulus ( US ) which evokes a reflexive
response with another neutral stimulus which does not
normally evoke the response (unconditioned response).
Following conditioning, the response occurs both to the
US and to the other neutral stimulus now referred to as
the conditioned stimulus ( CS ). The response to the CS
is termed a conditioned response.
Pavlov ( Russia ) experiment.
14. Pavlov experiment
Prerequisites :
1. Alertness with good health
2. Timing
3. Duration of CS – overlap US
4. Type of US – not motor
Reinforcement
Internal Inhibition ( Extinction )
External Inhibition
15. Classical conditioning
Physiological basis – formation of new
functional connections in CNS ( intracortical
or subcortical )
Molecular basis – Presynaptic fascilitation by
interneuron will increase after US activates
sensory neuron – increased NT release
16. Operant conditioning
In operant conditioning a certain behavior is
either rewarded or punished which results in
an altered probability that the behavior will
happen again or not.
Reward – Positive Reinforcement
Punishment – Negative Reinforcement
