Neuroplasticity Flashcards
What is neuroplasticity?
The ability of neurons to change their function, chemical, or structure
3 mechanisms of neuroplasticity
- Habituation
- Experience-Dependent Plasticity
- Recovery after injury
What is habituation?
A decrease in response to a repeated, benign stimulus
What is the time duration of habituation?
Temporary
What type of change is habituation? (chemical, structural, functional)
Chemical
What chemical changes occur in habituation?
Decreased release of neurotransmitters
Decreased release of Ca2+
Change in post-synaptic receptor sensitivity
Does habituation resolve after a period of no stimulus?
Yes
Habituation is due to what?
Decreased synaptic activity b/t sensory neuron and interneuron
If there is prolonged repetitions of stimulus in habituation, what kind of changes will occur?
Structural – more permanent changes
How does habituation allow for other types of learning to occur?
It tunes out “less important” info and focuses on “important info”
Techniques/Exercises to decrease neural response to stimulus (habituation)
Tactile defensiveness (cotton ball, light touch)
Vestibular Exercises
What is experience-dependent plasticity?
Persistent, long-lasting changes in strength of synaptic connections between neurons and within neural networks
What type of change is experience-dependent plasticity?
Structural
What is experience-dependent plasticity for?
Learning and memory
Examples of experience-dependent plasticity?
Playing an instrument, playing a sport
What structural changes occur in EDP?
Synthesis of new proteins
New synaptic connections
New dendrites, receptors, etc
Two types of plasticity in learning and memory
- Long-term potentiation (LTP)
- Long-term depression (LTD)
Long-term potentiation (LTP) occurs where in the neuron?
Pre-synaptic terminal
Long-term potential (LTP) changes what in the neuron?
Changes in amount of neurotransmitter
Long-term depression (LTD) occurs where in the neuron?
Post-synaptic terminal
Long-term depression (LTD) changes what in the neuron?
Changes receptor density and efficiency
What do astrocytes do in EDP?
Modulate neurotransmitter release and receptor expression
What do astrocytes release for synaptic connection modulation?
Gliotransmitters
What do gliotransmitters do?
Modulate synaptic connection
What is declarative memory?
Facts, events
Where is declarative memory stored?
Medial Temporal Lobe - Hippocampus
What is procedural memory?
Motor skills
Where is procedural memory stored?
Cerebellum, Basal Ganglia, Motor Cortex
Why is procedural memory stored diffusely?
If one area is damaged, there are still other areas retaining important motor skill memory for function
Process of axonal injury in PNS
Cytoplasm leaks
Segments retract (Wallerian Degeneration)
Glial cells clean up debris
Central chromatolysis
What is Wallerian Degeneration?
Distal segment of axon retracts away
What is Central Chromatolysis?
Cell body degenerative changes
What happens if post-synaptic cell loses synaptic inputs?
Cell death
What process occurs for recovery in the PNS?
Sprouting
What is regrowth of damaged axons?
Sprouting
What cellular changes occur for functional regeneration in the PNS?
Increase in NGF’s by Schwann Cells
Glial cell remove debris
Bands of Biingner guides regrowth to target
What is the timeframe of recovery in the PNS?
SLOW
What problem can occur from sprouting?
Axons can sprout in the wrong target causing wrong innervation
What problem can occur from regeneration of axons in the PNS?
Synkinesis
Altered Sensation
What is synkinesis?
Growth in wrong area
Can cause co-contraction of muscles
Is there axon regeneration in CNS injuries?
No (not yet)
What cellular events occur in trauma to CNS?
Damage to white fiber tracts
Increase membrane permeability & Na+/Ca2+
Disrupts axon transportation + build up
Axons swell + break
Proximal axons retracts (axonal retraction ball)
Distal axons = Wallerian degeneration, Central chromatolysis
