Neuroplasticity Flashcards
Neuroplasticity
Adaptive changes in structure or function of nerve cells in response to maturation injuries to nerve system or alterations in pattern of their use & disuse
Neuroplasticity occurs on several levels, including:
- Molecular (upregulation of proteins & gene expression)
- Single neuron level (synaptic plasticity)
- Network level (cortical maps)
- Systems level (within and across CNS)
Main points of Nudo study 1996
- As time goes on, individuals become more efficient with task
- Skilled training results in expansion of motor map in one area and decrease of motor map in another area
- Need to train your patient at their level so they are successful
Principles of training
- Many repetitions
- Progressive level of challenge
- Allow for success most of the time with some failure
- Motivation/reward
Changes in neuronal morphology in motor cortex
- Increase in dendritic branching
- Increase in dendritic spine density
- Increase in number of synapses per neuron
- Increase in number of perforated synapses
- Increase in number of synapses with multiple boutons
- Axon collaterals
Short term changes in synaptic plasticity
- Upregulation of neurotransmitters/receptors
2. Protein synthesis increases
Long term changes in synaptic plasticity
- Collateral growth
2. Spine and synapse formation
Main points in Kleim 2004 study
- With skilled training, there is an increase in hand area motor map versus unskilled training with no increase in motor map
- Reaching accuracy significantly increased between 3 and 7 days as well as 3 and 10 days
- Synapses need 7 days to change
- Maps change in 7-10 days
Ways to recover from lesion
- Recovery of function - minimize impairment, perform task like used to
- Compensation - adapt to impairment; modify how to perform tasks
Phases of recovery
- Rescue and salvage - few hours
2. Repair and recover - days to weeks to months; maximize adaptive plasticity
Reaction to cell damage
- Direct cell death
- Secondary cell death
- Diaschisis
Transneuronal changes
- Wallerian degeneration - primary damage
- Increase in synaptic efficiency of remaining synapses
- Denervation supersensitivity
- Unmask silent synapses
- Collateral sprouting
Main points from Nudo 2001 study
-Uninjured tissue adjacent to cortical injury undergoes functional reorganization that can be modulated by post-injury behavior training
Main points from Sawaki study 2008
- Use TMS to measure change in cortical maps
- With TMS, able to look at cortical maps, measure size of map, location of map, number of active sites, and threshold
Negative plasticity
-Get what you practice
Aging hypotheses
- Aging Machinery - Decline in function with age is inevitable and irreversible
- Negative plasticity - some aging effects are reversible; disuse, degraded input from periphery, negative learning
Reversal of negative plastic changes
- Intense training with many trials
- Motivation/reward
- Success most of the time
- Demanding, novel tasks
Motor Unit Discharge Pattern
- Initial increase in firing rate
- Synchronization of motor unit firing
- Increase in central drive
Effect of aerobic exercise on the brain
- Elevated levels of brain derived neurotrophic factor
- Increase in brain volume in older adults
- Improved cognitive function in older adults, post-stroke, and women with mild cognitive deficits
- Increase in recovery post stroke
- Increase in efficiency of dopamine in PD
