Learning

Question 1

Define learning

Answer 1

The relatively permanent change in an organism’s behaviour as a result of experience.

Question 2

What are the four types of learning?

Answer 2

Habituation
Sensitisation
Classical Conditioning
Operant Conditioning

Question 3

What is habituation?

Answer 3

Form of simple learning in which modification of behaviour occurs as a result of the repeated occurrence of a single stimulus.

Question 4

What is the process of habituation?

Answer 4

1. Stimulus elicits response
2. Response is always a reflex
3. Repetition of the stimulus leads to a reduced response.
4. Brain learns that it is safe to ignore stimulus

Question 5

What is sensitisation?

Answer 5

Another form of simple learning in which modification of behaviour occurs as a result of the repeated occurrence of a single stimulus.

Question 6

What is the process of sensitisation?

Answer 6

1. Stimulus elicits response
2. Response is always a reflex
3. Repetition of a stimulus leads to increased (reflex) response
4. Brain learns that stimulus could be harmful
5. Organism becomes hypersensitive to a stimulus, rather than accustomed to it.

Question 7

What is the neural basis of habituation?

Answer 7

Electrical recordings from the motor neuron show decreased excitatory postsynaptic potentials.
Motor neurons are receiving less neurotransmitter from the sensory neuron.
Reduced sensitivity of calcium channels (decrease in neurotransmitter release from presynaptic neuron)

Question 8

What is the neural process of sensitisation?

Answer 8

Interneuron releases serotonin onto the siphon sensory neuron
Serotonin activates ‘second’ messengers in the sensory neuron.
Increase cAMP concentration which binds to potassium gates.
Reduces sensitivity of potassium gates - slower to open, leading to longer action potentials
Longer APs leads to release of more neurotransmitter
Greater activation of motor neurons.

Question 9

What are the structural changes to neurons due to habitual learning?

Answer 9

Loss of synapses

Question 10

What are the structural changes to neurons due to sensitised learning?

Answer 10

Formation of synapses

Question 11

What is classical conditioning?

Answer 11

Learning procedure whereby a neutral stimulus comes to elicit a response because of repeated pairing with another stimulus. After learning, neutral stimulus elicits a response because of its repeated pairing with some event.

Question 12

What is fear conditioning?

Answer 12

Learning association between a neutral stimulus and a noxious event such as a shock. Involves circuits in the amygdala.

Question 13

What is operant conditioning?

Answer 13

Learning procedure in which the consequences of a particular behaviour increase or decrease the probability of the behaviour occurring again.

Question 14

What areas of the brain are involved in operant conditioning?

Answer 14

Temporal cortical areas such as basal ganglia and limbic system (dopamine-centred reward system)
For more difficult tasks, cortical areas are more likely to be involved (frontal).

Question 15

What is the neural basis of brain plasticity?

Answer 15

• Existing synapses become more complex
• New synapses are produced
• Old synapses may be lost
  Two mechanisms: long term potentiation and long term depression

Question 16

What is long-term potentiation?

Answer 16

A strong burst of electrical stimulation applied to the presynaptic neuron produces an increase in the amplitude of the excitatory postsynaptic potential in the postsynaptic neuron.

Question 17

What is long-term depression?

Answer 17

Neuron becomes less active in response to repeated stimulation. Decrease in amplitude of the excitatory postsynaptic potential in the postsynaptic neuron. Has a role in memory.

Question 18

What is the role of LTP and LTD in learning?

Answer 18

Frequently recruited neural pathways should experience LTP. This could be the basis for forming new memories and associations. Less frequently recruited pathways may demonstrated LTD.

Question 19

What is the influence of experience in cortical organisation?

Answer 19

Compared with rats raised in standard lab cages, those raised in “enriched environments” have:

• larger and more synapses
• larger and more astrocytes

Question 20

Describe the Nudo et al. (1997) study.

Answer 20

Monkeys retrieved food from small or large food wells
Digit representation on motor cortex (homunculus) was larger for animals retrieved food from smaller wells.
Digit representation of the animal with the harder task was increased.

Question 21

Describe the Ramachandran (1993) study.

Answer 21

When face stroked softly with a cotton swab, amputees reported sensations of being touched in the amputated hand. May explain “phantom-limb” as face and hands are close in the motor cortex.

Question 22

What is the homunculus?

Answer 22

“Little man” used to reflect the relative sensory space our body parts occupy in the cerebral cortex
Lips, hands, feet and sex organs are considerably more sensitive than other parts of the body, so these areas are large on the man.

Question 23

What effect does early deprivation of sensory experience have on the brain?

Answer 23

Atrophy of dendrites

Question 24

What effect does early deprivation of social experience have on the brain?

Answer 24

Profoundly negative effect on later intellectual and social behaviours

Question 25

What is the impact of stress early in life associated with in terms of the brain?

Answer 25

Increased amygdala activity

Decreased hippocampus activity.

Question 26

What are the three main solutions for recovery from brain injury?

Answer 26

1. Behavioural solution (change behaviour to compensate)
2. New circuit solution (brain forms new circuits)
3. Replace lost cells (stem cells)