PSY1003 SEMESTER 2 WEEK 1 - PART 2 Flashcards
when are majority of neurons in adult brain created
by 7th prenatal month
why is volume of brain increase 4x between birth–adulthood?
synaptogenesis, myelination, dendritic branching
outline the increase in synaptogensis in cortex after birth, and differences per region
v1, and auditory cortex initially post birth and big increase during 4th postnatal month, but prefrontal cortex is steady occurrence
where does myelination occur in brain post-birth
sensory areas in first few months after post-birth, motor area soon after, then continuing of prefrontal cortex into adulthood
explain how postnatal growths sensitive to experience
regressive change, synaptic and grey matter loss
outline what prefrontal cortex is most responsible for
cognitive developments, WM, planning, carrying out sequence, inhibitory control, following social norms or rule
describe perseveration and why error occurs during 7-12 month
tendency to continue making formerly correct response when it is currently incorrect, due to neural circuitry of prefrontal cortex not develop
outline a case study of ‘tiny brain’
postnatal hydrocephalus (build up of CSF within), with cycst blocked 4th ventricle however nearly normal functioning
outline research study with effects of early closure of one eye on distribution of cortical neurons driven by stimulation of both eye in cats
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
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
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
outline research into monocular deprivation affecting the width of ocular dominance colum in visual cortex (in monkey)
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
what ‘system’ is main visual pathway in humans
geniculostriate system
in humans outline geniculostriate system
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
what research studies can be done to show the striped ocular dominance column in monkeys
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)
what is critical period for language learning in humans
12 years
define critical period
window of opportunity where particular experiences may influence development, and is essential for these experiences to occur within particular timeframe for development to occur
define sensitive period
experience may have great effects on development within particular timeframe but can still have weak effects outside of timeframe
give research example for sensory deprivation
rats reared in dark show fewer synapses, less dendritic spines in V1. as adults, deficits in depth and pattern vision
give research example for sensory enrichments
rats raised in enriched cages than alone in barren showed thicker cortex, increased dendritic spine and more synapses per neurons
outline the impact of sensory restrictions in babies (relate to the critical periods)
born with cataracts (so almost blind), when removed 1-9month post birth, vision was comparable to newborn. visual deficit still present 2 years later
outline research into neuroplasticity visual cortex responding to braille in late-blind patients
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)
outline research on neuroplasticity for london cab drivers
bigger posterior hippocampus and positive correlation with time in job
give evidence of cats for axonal sprouting showing evidence of adults neuroplasticity
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
