PSY1003 SEMESTER 2 WEEK 1 - PART 2

Question 1

when are majority of neurons in adult brain created

Answer 1

by 7th prenatal month

Question 2

why is volume of brain increase 4x between birth–adulthood?

Answer 2

synaptogenesis, myelination, dendritic branching

Question 3

outline the increase in synaptogensis in cortex after birth, and differences per region

Answer 3

v1, and auditory cortex initially post birth and big increase during 4th postnatal month, but prefrontal cortex is steady occurrence

Question 4

where does myelination occur in brain post-birth

Answer 4

sensory areas in first few months after post-birth, motor area soon after, then continuing of prefrontal cortex into adulthood

Question 5

explain how postnatal growths sensitive to experience

Answer 5

regressive change, synaptic and grey matter loss

Question 6

outline what prefrontal cortex is most responsible for

Answer 6

cognitive developments, WM, planning, carrying out sequence, inhibitory control, following social norms or rule

Question 7

describe perseveration and why error occurs during 7-12 month

Answer 7

tendency to continue making formerly correct response when it is currently incorrect, due to neural circuitry of prefrontal cortex not develop

Question 8

outline a case study of ‘tiny brain’

Answer 8

postnatal hydrocephalus (build up of CSF within), with cycst blocked 4th ventricle however nearly normal functioning

Question 9

outline research study with effects of early closure of one eye on distribution of cortical neurons driven by stimulation of both eye in cats

Answer 9

shone light into 1/2 eye
most cells responsive for both eyes
where eye closed immediately post-birth, opened at 2.5month, some cells in visual cortex no longer responsive to light
with eye closed as adult and opened after 2 years, some cells found still responsive

Question 10

what does research into effects of early closure of one eye on distribution of cortical neurons driven by stimulation of both eyes in cat conclude

Answer 10

theres critical period in which if visual input is interfered with, cannot be gained back, due to connections dying, in cats this is 3 months

Question 11

outline research into monocular deprivation affecting the width of ocular dominance colum in visual cortex (in monkey)

Answer 11

column relating to non-deprived eye are wider than normal, and those related to deprived eye are shrunken. concludes that critical period in monkeys are 6 months

Question 12

what ‘system’ is main visual pathway in humans

Answer 12

geniculostriate system

Question 13

in humans outline geniculostriate system

Answer 13

info from both eye pass through dorsal lateral geniculate nucleus onto primary visual cortex.
left and right primary visual cortex receives info from both eyes
inputs carrying info from both eye forms alternating series of eye-specific domains in v1 cortex

Question 14

what research studies can be done to show the striped ocular dominance column in monkeys

Answer 14

inject tracer into an eye, travels to V1 cortex, then macaque, right hemisphere
shows striped ocular dominance columns, and show primary in layer 4 of visual cortex (area receiving input from thalamus)

Question 15

what is critical period for language learning in humans

Answer 15

12 years

Question 16

define critical period

Answer 16

window of opportunity where particular experiences may influence development, and is essential for these experiences to occur within particular timeframe for development to occur

Question 17

define sensitive period

Answer 17

experience may have great effects on development within particular timeframe but can still have weak effects outside of timeframe

Question 18

give research example for sensory deprivation

Answer 18

rats reared in dark show fewer synapses, less dendritic spines in V1. as adults, deficits in depth and pattern vision

Question 19

give research example for sensory enrichments

Answer 19

rats raised in enriched cages than alone in barren showed thicker cortex, increased dendritic spine and more synapses per neurons

Question 21

outline the impact of sensory restrictions in babies (relate to the critical periods)

Answer 21

born with cataracts (so almost blind), when removed 1-9month post birth, vision was comparable to newborn. visual deficit still present 2 years later

Question 21

outline research into neuroplasticity visual cortex responding to braille in late-blind patients

Answer 21

3 ppts, complete blindness post-puberty (cataract/glaucoma), PET using H2O15 (radiolabelled water), found that reading braile leads to V1 cortex activity (which would have only previously responded to visual stimuli found new purpose and respond to visual related info)

Question 21

outline research on neuroplasticity for london cab drivers

Answer 21

bigger posterior hippocampus and positive correlation with time in job

Question 21

give evidence of cats for axonal sprouting showing evidence of adults neuroplasticity

Answer 21

cat with retinal lesion made as adult, killed 8.5months post-lesion, injected tracer at edge of ‘blind cortex’, found fibres projecting into blind area had more elaborate arbour

Question 21

name 2 mechanisms that allows neuronal connectivity to continue plastic into adulthoods

Answer 21

axonal sprouting and adult neurogenesis

Question 22

outline adult neurogenesis

Answer 22

new neurons and glial cells can be generated reliably in olfactory bulb and hippocampus. area adjacent to lateral ventricles provide neuroblast/adult stem cell that later forms neurons in olfactory bulb and subventricular zone of lateral ventricles

Question 22

what is the area called in the dentate gyrus in the hippocampus where neurogenesis occur, and what happens to product

Answer 22

subgranular zone
get integrated into synaptic circuit, newly generated granule cells are contacted by GABAergic synapses in granual cell layer of adult hippocampus

Question 23

how many new neurons added to hippocampus per day?

Answer 23

around 700

Question 23

name some functions of neurons produced by adult neurogenesis

Answer 23

integrated into neural circuits, conduct neural signals, adult-generated olfactory bulb and striatal neurons become interneurons

Question 23

give an example of the effect of reorganisation of adult cortex

Answer 23

tinnitus - major reorganisation of primary auditory cortex

Question 23

what is the current theory of the role of adult hippocampal neurogenesis

Answer 23

important for pattern separation, ability to separate distinct percepts into individual memories for storage, role in mood/anxiety regulations
potentially role in physical activity- exposed to more cognitive challenges, and environmental adaptations