brain plasticity Flashcards
what does brain plasticity refer to
bp refers to the brains ability to change and adapt in response to new experiences, including brain damage.
adapting synapses, pathways, structures in the light of various experiences inc trauma
The brain’s ability to change and adapt in response to new experiences
The brain’s ability to change and adapt in response to brain damage
what are the mechanisms of bp
rewiring
synapse strengthening
neuronal unmasking
Explain how neuronal unmasking contributes to learning
Neuronal unmasking is when silent synapses become active and so reveal hidden neuronal connections between brain regions.
These hidden connections reactivate to help our brain to change and adapt to new experiences, which contributes to learning.
synapse strengthening
s
Synapse strengthening is when synapses between two neurons become stronger, making the transmission of nerve impulses between the neurons more likely.
Synapse strengthening causes an increase in the number of nerve impulses between neurons.
Synapse strengthening occurs due to increased amounts of neurotransmitters crossing the synapse.
Synapse strengthening occurs due to an increased amount of post-synaptic receptors.
who did the taxi driver study
maguire
what type of study was the maguires taxi drivers
quasi experiment
why was maguires a quasi experiment
exp as comparing 2 groups with different levels of the IV
didnt randomly allocate ps into the groups= couldnt control p variables (which may have influenced dv(size of ps brains)
didnt manipulate iv
iv was their job a personal characteristic (a difference between the 2 groups which already existed) This meant that she couldn’t assign her participants to the experimental group or control group; the participants already belonged to one group or the other
what did maguire use to compare the brains
MRI scanner
what were the differences between taxi driver and control brain
the findings indicated that the posterior hippocampi of taxi drivers were significantly larger relative to those of control participants
what was the correlation in maguires study
the posterior hippocampal volume was positively correlated with the amount of time they has spent as a taxi driver (a measure of their experience)
Maguire concluded that the experience of being a taxi driver led to changes in the brain, like rewiring. true or false
true
why cant maguires study establish c + e (counterbalance and limitation)
it could only show a correlation because it cannot be determined that the larger hippocampus was a result of being a taxi driver or that people with big H want to be taxi drivers/did the difference exist beforehand, we dont know what came first
didnt maniupulate iv
temporal precedence
Maguire concluded that the experience of being a taxi driver led to changes in the brain, like synapse strengthening. true or false
false
Maguire found that as time spent as a taxi driver increased, the size of a participants hippocampus also increased. What type of correlation does this describe?
positive correlation
why were the taxi drivers hippocampus’ bigger
because they had formed more neuronal connections in their hippocampus
rewiring
what does maguries study show support for
brain plasticity in humans
brain plasticity of adults
new experiences like taxi driving lead to changes in the brain that allow us to learn
does maguires study have ecological validity and why
yes because it was a real life experiment over time
what is the posterior hippocampus used for
long term memory, associated with the formation of new memories and the ability to navigate from one location to another, spatial navigation
Explain why participant variables may have been a problem in Maguire’s study.
Maguire’s study was a quasi experiment, which means that the participants were assigned to their groups based on their jobs, rather than any manipulation created by Maguire. This could be a problem, because there may be other factors (participant variables) related to being a taxi driver that could cause the difference in hippocampal volume, such as interest in talking to people, or a preference for driving.
What is the term for when new synapses are formed between two neurons that weren’t previously connected via a synapse?
rewiring
what did maguires study investigate
investigated taxi drivers to discover whether changes in the brain could be detected as a result of their experience of extensive experience of spatial navigation
what study shows support for bp in animals
kempermann
what did kempermann study research
used rats to investigate whether an enriched environment could alter the number of neurons in the brain
kempermann findings
compared to rats housed in lab cages, those rats housed in complex/enriched environments had an increased number of neurons in the brain particularly the hippocampus
kempermann conclusions
support for bp
exposure to enriched environment leads to changed structure of the brain
limitations to kempermann
animal study so can the findings be generalised to humans
who did the video games study
kuhn
kuhn video games study particpants
controlled group and experimental trained group (2 months at 30mins a day on super mario)
kuhn findings
showed a significant increase in grey matter in various areas of the brain including cortex, hippocampus, cerebellum, this increase is not evident in control group
kuhn conclusions
video game training resulted in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory, motor performance, skills that were important in playing the game successfully
does kuhn’s study have c+e and why
yes because the brains were scanned before and after exposure to iv therefore you can establish real change in response to experience
why is kuhn’s study a good lab experiment
controlled
random allocation
directly manipulated iv
c+e
didnt have p variables
Kuhn’s study found that learning is accompanied by plastic changes in the brain, like ….
rewiring not synapse strengthening
who did the study of bp on older adult juggling
boyke
what was the point of boykes study
to investigate the existence of bp in older adults to see if the natural decline in cognitive functioning that occurs with age, can be reversed
participants of boykes study
60 yrs olds
what did boykes participants do
observing the effect, on the brain, of being taught a new skill (juggling)
findings of boyke
increased grey matter in the visual cortex
what happened when boykes ps stopped practicing juggling
the changes (of increased grey matter) where reversed
what is grey matter
Grey matter is a type of tissue in your brain and spinal cord (central nervous system) that plays a crucial role in allowing you to function normally from day to day. It consists of high concentrations of neuronal bodies, axon terminals (endings) and dendrites.
who did the tibetan monks study
davidson
ps of davidson’s study
8 practitioners of tibetan meditation compared with 10 student volunteers with no previous experience of meditation
how was data collected in davidsons study
both groups were fitted with electrical sensors and asked to meditate for short periods
findings of davidsons study
the electrodes picked up much greater activation of gamma waves(which coordinate neuron activity) in the monks
students only showed a slight increase in gamma wave activity while meditating
conclusions of davidsons study
meditation not only changes the brain short tem but may produce permanent changes as the monks had far more gamma wave activity than the control group even before they started meditating
limitation of davidsons study
had volunteers
has ccv
what is functional recovery
refers to the recovery abilities and mental processes that have been compromised or lost as a result of brain injury or disease
refers to the brains ability to change and adapt, only after brain damage
functional recovery can be achieved as a result of ….. through ….. and …..
bp through neural reorganisation (rewiring) and neural regeneration
what are some types of brain truama that can result in a loss of function
physical trauma eg blows/missle wounds to the skull and brain
viral or bacterial infections that destroy brain tissue
stroke (cerebral haemorrhage or cerebral ischaemia
what can trigger neural reorganisation
neural regeneration
how are stems cells used for neural regeneration
by implanting them into damaged areas they have the potential to grow into neurons and make functional synaptic connections that help restore brain functions
3 ways that would stem cells work to provide treatment for tbi
by directly replacing dead or dying cells
transplanted stem cells may secrete growth factors that rescue/rejuvenate the damaged cells
transplanted cells form a neural network which links uninjured brain site with the damaged region of the brain
what is the evidence for role of stem cells in neural regeneration
tarjiri RANDOMLY assinged rats with TBI to one of two groups. 1 received transplanted stem cells into the region affected by tbi
control received a solution diffused into the brain with NO STEM CELLS
3 months after tbi, 1 had development of neuron like cells in area or injury and solid streamof stem cells migrating to site of injury
none of this for 2
what are dormant synapses
synapses that exist anatomically but their function is blocked as they arent sufficiently stimulated/rate of neural input is too low to be activated
what happens to dormant synapses when the surrounding area becomes damaged
the rate of input increases unmasking the synapses
what happens when synapses are unmasked: opens connections to regions of the brain that…
opens connections to regions of the brain that are not normally activated creating a lateral spread of activation which over time allows development of new structures
what are the 2 structural changes that support neural unmasking
axonal sprouting from surviving neurons
recruitment of homologous areas
what is axonal sprouting
when axons of surviving neurons grow new branches that make synapses in areas of the brain formerly supplied by the damaged neuronsw
what is the recruitment of homologous areas
rain behaviour becomes active in the equivalent part of the brain on the opposite hemisphere, enabling neural reorganisation and functional recovery
what does CIT stand for
constraint induced therapy
CIT suggests that the practice of a skill….
that has been affected by brain damage may lead to significiant improvement
observed improvement was due to reorganisation of cortical networks
what are the 2 factors affecting functional recovery
age and cognitive reserve
what age does the brain mature
around age 25
what is the view that links b/fp with age
functional plasticity reduces with age
what did elbert conclude: capacity for neural reorganisation
is much greater in children than in adults
what is elberts conclusions demonstrated by: the extended
the extended practice adults require in order to produce changes
participants of teuber
soldiers with brain damage
in 2 groups: under 20 and over 26
teuber conclusion
recovery from movement and visual problems in adulthood was age dependent
axonal sprouting and reorganisation may be more extensive in the younger brain
bp and fr is possible in adults
teuber findings
60% in under 20 groups showed significant improvement whereas only 20% in over 26 group showed similar recovery
limitation of teuber: “brain damage”
to what extent was the brain damage of the ps (participant variables/differences)
they could differ due to physiological and psychological trauma confounded with length of service and this could impact recovery
PTSD could also affect recovery
limitation of teuber: sample
the groups had very different age range (small vs big) which makes it difficult to compare results as you cant separate age from other factors in predicting recovery
can you establish c+e in tuebers study and why
no because it was a quasi experiment and there were several uncontrolled variables
what did kapar find
recovery after brain damage was better in docotrs than in the general public
When Patricia Neal had a stroke, damaging her left hemisphere, what abilities did she lose?
The ability to move the right hand side of her body
The ability to understand and produce speech
what is functional recovery
when a function is transferred from a damage region to an undamaged brain region
When a function is regained after brain damage, because it is transferred from the damaged brain region to an undamaged brain region.
what are the three mechanisms for functional recovery
synapse strengthening
rewiring
unmmasking neuronal connections
Normally, a nerve impulse is only triggered in the post-synaptic neuron if multiple EPSPs…
summate
what can neurons do to increase the amount of nerve impulses
increase the amount neurotransmitters release
increase number of receptors on post synaptic neurone so more charged particles enter post synaptic neurone
what is synapse strengthening
when the likelihood of nerve impulses being transmitted between two neurones increases
which synapses are strengthened
the ones near the area of the brain damage
what is rewiring
Axons from brain regions that used to communicate with the damaged region rewire to form connections with nearby brain regions.
when neurones they werent already connected to
.new neuron connections are formed between two neurons that aren’t already connected.
Describe two ways synapses can be strengthened, and how this affects the likelihood of nerve impulses being transmitted.
increase number of neurotransmitters released by presn, more NT bind to postsn= more charged particles into postsn
increase no of receptors available to pick up NT on postsn, more nt bind to postsr=more charged particles in postsn
both increase likelihood of nerve impulses being transmitted between the 2 neruones=synapse has been strengthened
