Neuroplasticity Flashcards
use it or lose it
failure to drive specific brain functions can lead to functional degradation
use it and improve it
training that drives specific brain function can lead to enhancement of that function
Specificity
the nature of training experience dictates the nature of plasticity
Repetition Matters
induction of plasticity requires sufficient repetitions
intensity matters
induction of plasticity requires sufficient training intensity
time matters
different forms of plasticity occur at different times during training
salience matters
the training experience must be sufficiently salient (be important) to induce plasticity
Age matters
training-induced plasticity occurs more readily in younger brains
transference
plasticity in response to one training experience can enhance the acquisition of similar behaviors
interferences
plasticity in response to one experience can interfere with acquisition of other behaviors
plasticity occurrences in nervous system
- neurodevelopment (childhood)
- learning (adult)
- recovering from injury
two forms of long-term memory
explicit and implicit
explicit
facts and events
implicit
emotional response, skeletal musculature, and cerebellum.
what happens to Non-declarative learning an individual with severe deficits in declarative learning
- can’t make any new memories
- ability to improve on simple motor task
- looking into mirror trying to draw star (backwards)
neuroplasticity
ability for nervous system to change and adapt
Neuroplasticity changes in physiology
changes in nerve threshold, conduction velocity, and synpatic efficiency
Neuroplasticity in anatomical morphology
changes in structure & connectivity
Neuroplasticity changes in behavior
learning or recovery of function
Measuring Neuroplasticity: Synaptic efficiency
- pre & post synaptic changes (changes type and number of receptos)
- long term potentiation
Measuring Neuroplasticity: neuronal morphology
increase in dendritic spines post learning
Magnetoencephalography (MEG)
Use of magnetic filed to track neuronal activity
Position emission tomography (PET)
Radioisotopes used to track metabolic activity
Functional MRI (fMRI)
Tracking oxygenated blood flow in the brain
changes in neural activity in fMR =
changes in blood flow
development of plasticity
- genesis of neurons
- genesis of connections
- elimination of cells and synapses
- activity-dependent synaptic rearrangement
activity dependent synaptic rearrangement
- synaptic segregation
- synaptic convergence
- synaptic competition
- modulatory influences
synaptic segregation
critical period
synaptic stabilization
neurons firing together to strengthen function
synaptic convergence
critical period
visual environment influences development
synaptic competition
mechanism
inputs compete for synaptic control of postsynaptic neuron
modulatory influences
mechanism
presence of neuromodulators may promote synaptic alterations (seratonin)
Apoptosis
cell death that is genetically programmed
competition for trophic factors
trophic factors
life sustaining nerve growth factor
what happens when there is a loss of synapses
Ach is release but does not connect to postsynaptic receptor & the neuron will die
Differences between developmental and adult plasticity
During development –> global and dramatic changes
In adulthood —> changes in synaptic strength
global and dramatic changes that occur during development
Changes in projections and connectivity
Structural changes
Rapid changes at critical periods
changes in synaptic strength that occur during adulthood
Cell death
Dendrite arborization
Synaptic rearrangement
Shared Mechanisms Between Development and Adult Learning
*competition for synaptic sites
In development = survival of connection
In adults = strengthens the synapses
Rules of Synaptic Plasticity when presynaptic axon is active & at the same time the postsynaptic neuron is strongly activated under the influences of other inputs
the synapse for presynaptic axon is strengthened
Neurons that fire together wire together
Rules of Synaptic Plasticity when the presynaptic axon is active & at the same the postsynaptic neuron is weakly activated by other inputs
the synapse is weakness
Neurons that fire out of sync lose their link
Hebbian learning
“when you see a rose, you can smell it”
two stimuli activated at the same time - likely to remember
synaptogenesis
growth of new synapse connections
Long Term Synaptic Potentiation (LTP)
increase postsynaptic response & long lasting increase over time
molecular changes related to Long Term Synaptic Potentiation (LTP)
- phosphorylation of proteins
- increase in postsynaptic AMPA receptors
- NMDA mediated
- AMPA upregulation
Long term depression in cerebellum (LTD)
Cerebellum is a comparator in motor control
simple = kinesthetic information complex = error signals
LTD vs LTP
NMDA trigger and Ca+ entry both LTD and LTP
Block NMDA receptors and LTP cannot occur
Motor Cortex Contribution to Procedural Learning (stages)
Early - decrease in reaction time / increase cortical maps
Middle - recognize sequence is present
Late - learns sequence - cortical maps back to baseline
the shift of automatic stage of skill acquisition is associated with
reduction in cortical activity
increase activation in subcortical centers
Cortex Motor Learning
Increase synaptic efficiency between somatosensory and motor cortices
Once learned, somatosensory cortex takes less role in activation of motor cortex
memory engrams
Widely distributed group of neurons comprising of smaller functional groups
- Neurons that fire together wire together
- Neurons that fire out of sync lose their link
