Plasticity Defined
the modifiability the brain with short term changes in efficiency & strength and long term changes in organization and number
-it is environmentally dependent neuronal reorganization
2 conditions under which plasticity occurs
- adaptive mechanism of injury (damage)
- typical brain development (beginning of life & adulthood )
- ->critical period in first 1-2 yrs in which certain skills must be learned or they will never be formed
Plasticity: Learning Occurs when…
- internal changes w/in synapses (amy of NT released) of the neurons occur
- increase in the number of synapses b/t neurons
Functional plasticity
brains ability tome functions
–>when an are of the brain has damage, need to move function so another area can take over/compensate for that damage/loss
Structural plasticity
ability to changes structure w/ inc synapses or cortical re-mapping
Acquisition of Skills: brain during critical period
- always “on”
- unregulated change in response to overflow of stimuli
- mass synaptic formation (very little/no synaptic pruning)
Acquisition of Skills: brain during adulthood
- periods of “off”
- able to generate reliable & coordinated responses
- synaptogenesis and pruning are more balanced
Recovery of Function
recovery= requisition of skills function= complex neuronal activity related to the performance of a task
Things impacting recovery of function…
- age
- neurotropic factors
- pre/post injury factors
- characteristics of lesions
plasticity & recovery of function d/t Injury occurs at many levels…
- intracellular level
- intercellular level
- network level
- brain level
- biochemical level
- genetic level
After injury may see: Denervation of Supersensitivity
hypersensitivity to stimuli of the post-synaptic cell following damage
After injury may see: Unmasking of Silent Synapses
brains ability to recruit synapses infrequently used when “primary synapses” are damages
After injury may see: neuronal Regeneration
new growth of neurons
After injury may see: Collateral Sprouting
synapses from surrounding area “sprout” over into the damaged area to compensate
Recall Schema
selection of specific responses among past movement outcomes
recognition schema
evaluation of response against past movement outcome
Theories of motor Learning
- Schmidts schema theory
- Ecological theory
Schmidts Schema Theory
- motor learning is an ongoing process of recall and recognition
- variability of practice will improve this motor learning
- RULE BASED
- ->does not account for immediate acquisition of motor skills
Ecological theory
Use of perceptual cues to perform the most efficient outcome–>perceptual info drives motor info
ex. drinking from a glass, need to know what force to use & how far away the cup is from our mouth…
Limitations to ecological theory
newer theory, not much evidence to support it
Clinical Implications of ecological theory
- repeated practice under varying conditions
- using relevant perceptual cues to create OPTIMAL motor strategies
Fits & Posners 3 stages of motor learning
Cognitive: what has to be done? assessment of the task
Associative: how to do it best? refinement of motor pathways
Autonomous: how to succeed? movement planned at higher levels
