brain development and plasticity Flashcards
germinal period
0 - 2 weeks
time from conception to implantation
over half don’t successfully implant
embryonic period
2 - 8 weeks
heartbeat begins
recognisable body parts appear
sexual differentiation begins
fetal period
9 weeks - birth
rapid growth of body and brain
sensitive periods
optimal times in devlopement when certain areas of the brain are most ready to benefit from experience
neural proliferation
the multiplication or reproduction of neural cells
neural differentiation
the development of neurones from neural stem cells
natural selection and migration
certain skills are needed to survive
cultural adaptation to the environment e.g. in times of stress
synaptic formation and maintenance
the formation of synapses between neurones
and changes to accommodate to the transmission
periventricular heteropia
no migration from ventricles
cobblestone cortex
large numbers of neurones don’t reach the cotes
no normal cortical layers are formed
glioneuronal heteropia
neurones overshoot the votes and end up in the subarachnoid space
polymicrogyria
disrupted cortical organisation
synaptogenisis
number of synapses increase 10 times in the first year
infancy brain growth
75% of adult size
most growth in size of neurones
environment affects the brain
infant plasticity
by 2 - double synaptic connections
by 3 - triple synaptic connections
compared to adults
synaptomgenesis and pruning
first 10 years the brain is twice as active
in the 2nd decade pruning is complete in visual areas
synaptic pruning
a process in which the brain removes neurone and synapses that it does not need
myelination
formation of the myelin sheath around a nerve to allow for improved conduction
grey matter
neutron cell bodies
dendrites
myelinated and non-myelinated axons
glial cells
synapses
capillaries
white matter
deeper in the brain
fewer cell bodies
long range militated axons
necrosis
unplanned cell death
can lead to neurodegeneration
apoptosis
planned cell death
can lead to neurodegeneration
neurodegneration
chronic, incurable conditions that progressively damage nerve cells in the brain
dementia, physical trauma, untreated mental disorders
atrophy
ageing
neurons will die with age due to irreversible damage but can still increase in complexity
no neurotransmissions
dendtric length and complexity
increase in length along with age, up to a certain point, but loose complexity
white matter loss
more loss in anterior than posterior
more WM in posterior to begin with
brain activity
decrease in some activity due to loss of ability to engage in strategies and recruit
increase in some activity due to non-specfic recruitment
mechanisms of cognitive ageing
inhibitory deficit hypothesis - decreased ability to suppress irrelevant information that interferes with ongoing processes
compensation hypothesis - increased neural activity of additional brain regions to counteract dysfunction
dedifferentiation hypothesis - reduced specifics of neural signature to discrete tasks
memory retrieval
over recruitment of frontal lobes
connectivity
temporal correlations between brain regions, either automatically or functionally for a particular task
plasticity at a cellular level
regeneration of neurone - possible in CNS
generation supersensitivity - hypersensitivity of intact cells to stimulation
rerouting - neurone looses a connection and connects to a new one
sprouting - new connection via new growths within a neutron
brain reorganisation
early damage = maximal reorganisation
but not necessarily all cognitive functioning
acquired lesion
the larger the lesion, the lower the IQ
congenital lesion
older age associated with poorer intellectual performance
crowding hypothesis
individuals with left hemisphere brain injury experience a reorganisation of language function to the right hemisphere
