Lecture 13: Neuroplasticity Flashcards
what is neuroplasticity
The brain’s ability to modify, change, and adapt throughout life and in response to experience
The connection between neurons can be modified: synaptic plasticity
what are the 3 basic aspects of neuroplasticity
Neuroplasticity includes several different processes
It is continually taking place throughout the lifespan
It can be maladaptive in some cases
are connections between neurons static or dynamic
dynamic.
there is constant changing based on our experiences
neuroplasticity forms the basis of what?
neurorehabilitation
what is Homosynaptic Plasticity
Changes in synaptic strength localized to a post-synaptic target neuron stimulated by its own pre-synaptic neuron
what is Heterosynaptic plasticity
activity of a neuron leads to changes in the strength of synaptic connections of other neurons
example: Interneurons release other neurotransmitters that act on the synapse
what are the Two main types of Short-Term Plasticity
Short-term potentiation
Short-term depression
what is Short-term potentiation
Short-term ↑ in synaptic strength
Neurons that fire together, wire together
what is Short-term depression
Short-term ↓ in synaptic strength
Neurons that fire out of synch, lose their link
what are the two types of Long-Term Plasticity
Long-term potentiation
Long-term depression
what is Long-term potentiation
Long-term increase in
synaptic connections
what is Long-term depression
Long-term decrease in
synaptic connections
what is the Neuroplasticity Time Frame
Short term changes in synaptic strength
- Temporary functional changes from short term potentiation and depression that take seconds
Long term changes in synaptic strength
- More permanent, structural changes caused by long term potentiation and depression that take minutes to hours
what are the 4 mechanisms of Long-term potentiation and its result
Ca2+ enters the post-synaptic cell to act as a secondary messenger
Glutamate is released from the presynaptic neuron and binds to AMPA receptors
More AMPA receptors are added
↑ in number, size & length of dendritic spines
Results in strengthening of synaptic transmission (LTP)
To change synaptic plasticity on a long-term basis requires which 2 things
Gene transcription
Protein synthesis
what are mechanisms for Long-Term Depression
Removal of AMPA receptors from post-synaptic membrane
Can’t continually strengthen synapses – needs to be a mechanism to selectively weaken synapses (synapsing pruning)
Low frequency continuous input (the brain doesn’t think something is important)
LTD and LTP have opposing but complementary functions (they abolish each other)
what is the result of Long-Term Depression
Postsynaptic membrane is less likely to be depolarized
How do our brains know which synapses to strengthen or weaken?
Repeated, high frequency stimulation of sufficient amplitude→LTP
Repeated, low frequency stimulation while postsynaptic membrane is hyperpolarized or weakly depolarized→LTD
what is the Role of Dopamine in Plasticity
Can affect synaptic plasticity by modulating AMPA and NMDA receptors
how is CNS injury different from PNS (3 ways)
Neuronal death
Overgrowth of glial cells contribute to glial
scarring
Axonal regeneration severely hindered
Recovery after brain injury is primarily due to what
reorganization of function using remaining intact circuits rather than repair of damaged brain tissue
what is an Ischemic stroke
Blockage that prevents the brain from getting blood flow
what is Penumbra:
Reversibly injured brain tissue around ischemic core
what is Synaptogenesis
Formation of new synapses
main type is reactive synaptogenesis
what is Reactive synaptogenesis
(collateral sprouting)
* Neighbouring axons sprout to innervate synaptic sites previously activated by injured axons
what is Neurogenesis
Birth of new neurons
what is Cortical Reorganization
Sensory and motor maps undergo constant revision so another part of CNS takes over an area of lost function
what are the 4 aspects of Experience-Dependent Plasticity
Early in learning and after brain injury, many regions of the brain are active
With repetition, the number of active areas decreases because we get more efficient
Cortical reorganization can occur well after injury
These changes are consolidated during sleep
what is the relationship with performance and brain activity in Experience-Dependent Plasticity
as our performance improves, the amount of brain activity decreased
Does Exercise Promote Neuroplasticity?
Executive function is most responsive to aerobic exercise
Memory most responsive to resistance training
How does Exercise Promote Neuroplasticity? (3 ways)
Increases growth factors
Promotes cortical reorganization
Increases the complexity and density of dendritic spines
what are the 5 Clinical Implications of neuroplasticity
Activities need to be both repetitive and challenging
Need to consider treatment dose when prescribing therapy
Activities must be meaningful
Create an environment that is conducive to plasticity
Activity is important
why are Repetitive and Challenging Activities important for neuroplasticity
Constraint-Induced Movement Therapy: increased motor map area
Performance of skilled motor tasks promotes neuroplasticity
why is Treatment Dose important for neuroplasticity
More therapy usually results in better outcomes
Timing also matters
why are Meaningful Activities important for neuroplasticity
Plays a role in reward, motivation, and reinforcement
dopamine release is linked to the meaningfulness of a task
why is Environment important for neuroplasticity
Exercise priming (exercise before therapy can decrease GABA (inhibitory) may increase cortical excitability
why is Activity is Important for neuroplasticity
Prolonged lack of movement can result in loss of function in undamaged adjacent areas
Match the correct statement to the type of short-term plasticity
Short-term depression: increase in neurotransmitter
Short-term depression: short-term decrease in synaptic strength
Short-term potentiation: decrease in the availability of neurotransmitter
Short-term potentiation: short-term decrease in synaptic strength
Short-term depression: short-term decrease in synaptic strength
Which of the following statements are correct regarding homosynaptic and heterosynaptic plasticity?
Interneurons are not involved in homosynaptic plasticity
Homosynaptic plasticity is more localized than heterosynaptic plasticity
All of the responses listed are correct
In homosynaptic plasticity, the postsynaptic neuron is stimulated by its own presynaptic neuron
All of the responses listed are correct
When Adria’s dog Tui heard the fire alarm go off for the first time which scared her, what likely happened to her synapses within the first few milliseconds or seconds?
Neither structural nor functional changes
Mostly functional changes
Mostly structural changes
Structural and functional changes
Mostly functional changes
Which of the following responses is true regarding CNS injury in comparison with PNS injury?
There is less neuronal death following CNS injury
There is glial scarring following PNS injury
Axonal regeneration is not possible following CNS injury
Axonal regeneration is very limited following CNS injury
Axonal regeneration is very limited following CNS injury
