brain learning and motivation: brain behaviour- neuroplasticity

Question 1

the brain and plasticity: plastic nature of brain

Answer 1

the brain sis most plastic early in life
as humans we adapt and change in our environment this is due to plastic nature of brain
brai changes over time due to experience injury etc this is also due to plastic nature of brain

Question 2

typed of plasticity

Answer 2

plasticity in neurons
dendritic branching
long term potentiation
neurogenesis

Question 3

types of plasticity: plasticity in neutrons

Answer 3

Neurons can compensate for injury or disease or to adjust their ac0vi0es in response to new situa0ons or changes in the environment.

Question 4

types of plasticity:dendritic branching

Answer 4

the brain can rearrange the connections between neutrons

Question 5

types of plasticity: long term potentiation

Answer 5

Learning can increase/decrease neurotransmission between specific neurons

Question 6

types of plasticity: neurogenesis

Answer 6

The brain can generate new neurons throughout lif

Question 7

Donald Hebb

Answer 7

• Hebbian theory describes a basic mechanism for synap0c plas0city where an increase in synap0c efficacy arises from the presynap0c cell’s repeated and persistent s0mula0on of the postsynap0c cell.
• ‘Let us assume that the persistence or repe00on of a reverberatory ac0vity (or “trace”) tends to induce las0ng cellular changes that add to its stability…. When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased.’

often figuratively denoted:
those who fire together wire together

Question 8

in order for learning to take place

Answer 8

neurons must change the way they func0on, both internally and in their communica0on with one another.
involves Long Term Poten0a0on or LTP
- neural change at the synapses is ac0vity
dependent

Question 9

Aplysia

Answer 9

most of what we know aout neuronal plasticity comes from this marine mollies
it has an extremely simple nervous sysstem
its classically conditioned
The animal is first touched lightly on its siphon (CS), then shocked on its tail (US), both of which it retracts when threatened. Eventually, the animal responds to the CS alone, retrac0ng its tail when touched.
• Eric Kandel - Nobel prize 2000
• Habitua0on and Sensi0za0on

Question 10

long term potentiation

Answer 10

If neuron A fires over and over, neuron C will become more responsive to A than it was ini0ally. This is the poten0a0on effect. If neuron B tends to fire at the same 0me as neuron A, then it too will benefit from this poten0a0on.
relies on connections already made

Question 11

the spread of potentiation

Answer 11

is ac0vity dependent — spreading only to neurons that were ac0ve at the same 0me as the neuron that caused the poten0a0on in the first place.

Question 12

plasticity and development

Answer 12

early in development brain is more plastic
evidence for this:
Neural growth in infancy and early childhood
– The effect of environment on brain growth
– Recovery from brain damage in infancy and early
childhood

Question 13

plasticity in development: rate of growth

Answer 13

Brain development process leads to massive growth of the brain from 350 grams to about 1,250 grams (about 80 percent of the adult size) by age 4
• At key stages synap0c pruning occurs • Unused connec0ons are severe
• Growth happens in spurts
• Brain spurts last for around 2 years.
– Occur at approximately the ages of 2, 6, 10, & 14
– Each growth spurt adds about 10% of weight to the brain
– During this 0me, the neurons are establishing new connec0ons and withdrawing old, redundant ones.

Question 14

rate of growth: before two years old:

Answer 14

– Rate of making new connec0ons is greater than the removal of old ones
– Therefore at 2 the number of connec0ons is at a maximum

Question 15

rate of growth: after 2 years old

Answer 15

– Rate of withdrawal is greater than making of new
connec0ons
– A fully func0oning adult has around half the number of connec0ons as a young child

Question 16

environment and the brain

Answer 16

Children need s0mula0on for op0mal brain
developmentPerry, B. D. (2002). Childhood experience and the expression of genetic potential: What childhood neglect tells us about genetic/ environmental interaction. Brain and Mind, 3, 79-100

Question 17

Not just changes in connec0ons, but new cells as well. Can result in…

Answer 17

• Increased cor0cal thickness
• Increased cor0cal neuronal cell body size • Increased dendri0c branching
• Increased cholinergic func0oning
• Increased glial cells
• Increase in new neurons
• Increase in capillary branching

Question 18

motor training: Exercise (running) may be good for the brain

Answer 18

 Motor ac0vity itself increases number of blood capillaries (increased glucose and oxygen)
 Improves spa0al learning
 Increases LTP (mechanism for learning)  Increases neurogenesis

Question 19

learning something new changes your brain

Answer 19

Woollet and Maguire (2011)
• From their paper in Current Biology:
• Trainee taxi drivers in London spend 3–4 years learning the city’s layout
• They assessed the brain and memory of trainees before and a[er this long training
• Those who qualified experienced increased gray macer in posterior hippocampus

Question 20

Brain damage

Answer 20

Full recovery is most likely if damage occurs in early childhood
– Up to 7 years old a child can recover normal func0on a[er a Hemispherectomy
– Earlier is becer for language
– Adults can also survive, but are likely to suffer issue with mobility and if on the le[ side, would lose language communica0on

Question 21

more on brain damage

Answer 21

• Stroke or brain injury can be devasta0ng at the 0me, but pa0ent regain most func0ons
• Remapping in the cortex
• Making new Connec0ons to bypass damage
• Conscrip0ng redundant/underused regions – Sara Scoc

Question 22

Phantom Limb Phenomenon

Answer 22

• Phrase introduced by Silas Weir Mitchell (1871, 1872)
• Es0mated 90% of amputees experience a vivid phantom limb (seen less in children)
• Immediate in 75% of cases, as soon as anesthe0c wears off

 Dura0on: few days to decades
•  All body parts
•  Most o[en painful
•  May be stuck in ‘habitual’ posture •  Involuntary movement
•  Sensory memories

Question 23

sensitive periods

Answer 23

Plas0city is not infinite
– To learn a language a baby/child need exposure to it at the right tome
– Adults find it much harder to learn new languages
– Sensitive period for language is infancy and early childhood