Topic 8 (Learning)

Front 1

What is the critical period

Back 1

Period in early in life > responsible for development of important abilities e.g. vision

Front 2

What is the structure of the visual cortex

Back 2

• in cerebral cortex (back of brain)

• ODCs = grp of neurones in visual cortex > arranged in alternating pattern & columns same size

Front 3

Describe the role of visual stimulation on the development of the visual cortex during the critical period? 4 marks

Back 3

• ocular dominance columns (develop in the visual cortex)

• neurones form synapses with these cells/ columns

• stimuli/ action potentials/ impulses along neurones required to strengthen connections (with cells of ocular dominance columns)

• stimulation during the critical period is needed to form (effective) connections in the visual cortex

Front 4

Animal models > kittens (Hubel & Wiesel)

Back 4

• Vision (eye sewn shut) > young kitten blind > adult cat fully recovered vision

• ‘switched dominance’ > ODC’s for open eye expanded to take over function of columns x stimulated

• ODCs > young kitten - lack of visual stimulation = smaller ODC’s > adult cat - ODCs remained the same

• Results > critical period for visual development early in life

Front 5

What do animal models show about development of vision?

Back 5

when BOTH eyes visually stimulated early in life ocular dominance columns develop properly (> & visual cortex)

Front 6

Human observations for visual development (Cataracts)

Back 6

• cataract makes the lens in eye go cloudy causing blurry vision

• baby remove within first few months > vision develops

• adult not as serious > when removed normal vision comes back straight away (AS visual system is already developed)

Front 7

Arguments against the use of animals (minimum 3)

Back 7

• suffer due to pain/distress

• cant give consent (whereas humans can)

• physiologically different > unrepresentative

• alternatives to using animals in research e.g. use a culture of human cells

Front 8

Arguments for the use of animals (minimum 3)

Back 8

• animals in pre clinical trials to test drugs > only way to see how drug effects a whole body

• only done when necessary & strict regulations e.g. painkillers to reduce pain

• improves understanding of human physiology/ physiologically similar

• humans have ^ right to life than animals due to ^ complex brain (preferable to testing on humans)

• utilitarianism > benefits outweigh costs > saving many lives

Front 9

Animal models > monkeys

Back 9

• repeated experiment done on cats on monkeys > same results

• if both eyes visually stimulated in early stages of life > OCDs correctly form > visual cortex forms properly

Front 10

Habituation

Back 10

The decrease in response to a repeated/ unimportant stimulus

Front 11

Why is habituation beneficial

Back 11

- x waste energy responding to unimportant stimuli

- ^ time spent doing activities for survival e.g. feeding

Front 12

Investigate habituation to a stimulus

Back 12

• IV: number of pokes with a cotton wool bud

• DV: time taken for animal to respond measured using a stopwatch e.g. time taken for tentacles to re-emerge from the shell

•CV: organism of same species, same size & age, same cotton wool bud, where bud touches is the same

• response time > if habituation organism reacts slower not alert to familiar stimulus

•repeats

Front 13

CNS during habituation

Back 13

1) repeated exposure > decrease in amount of calcium ions entering presynaptic neurone (Ca+ ion channels less responsive)

2) decrease in the influx of Ca+ means less neurotransmitters released from vesicles into synaptic cleft

3) neurotransmitter x bind to receptors on post synaptic membrane

4) fewer Na+ channels open on the post synaptic membrane > reduced chance that threshold for action potential to be reached

5) fewer electrical impulses sent to effector to carry out response

Front 14

Nature & nurture

Back 14

Nature = genetic

Nurture = environmental

Front 15

Animal experiments

Back 15

• effect of nurture > animals of same species (nature controlled)

• effect of nature > genetically engineer genes

Front 16

Twin studies

Back 16

• effect of nurture > raised in dif environment (nature controlled as genetically identical)

• effect of nature > if MZ twins ^ similar than DZ

Front 17

Cross cultural studies

Back 17

effect of nurture > environment differs

Front 18

Newborn studies

Back 18

• effect of nature measured

• no effect of nurture

Front 19

Brain damage studies

Back 19

• effect of nurture measured > damaged region of brain

Front 20

Limitations of twin studies

Back 20

• Nurture not different > there are environmental factors that are the same 1) in womb 2) raised together > similar env

Front 21

What is the critical period > vision

Back 21

Period in life when exposure to visual stimuli is essential to visual development