Plasticity Flashcards
What are the 4 types of glial cells?
ependymal cells
oligodendrocytes
microglia
astrocytes
What do ependymal cells do?
lining of ventricles (CSF)
What do oligodendrocytes do?
Creates myelin sheath
What do microglia do?
“policemen”
clean up the debris
What do astrocytes do?
Scaffolding for brain
Most abundant
What are the 5 kinds of neurons?
pyramidal
purkinje
granule
spindle
interneuron
What are pyramidal neurons?
Found in the cortex – usually associated with initiation of movement and thought
What are purkinje neurons?
Found in the cerebellum – multiple feedbacks for precise movements
What are granule neurons?
Found throughout the brain, cerebellum, olfactory, and hippocampus
What are spindle neurons?
Connections to different parts of the brain
*May be involved in some psych disorders
What are interneuron neurons?
connections between to help regulation, usually inhibitory
What is plasticity?
The ability for neurons to adapt and perfect the flow of information with inflow or outflow.
What the 2 main points of plasticity
Arborization
De-arborization
What is Arborization?
The process in which connections are made including dentrites, axons, and/or telodendrites. (synaptogenesis)
Can enhance a skill/memory
The point is to allow better ease of depolarization
Over-arborization can lead to problems including:
increased reflexes, pain, or the inability to process information
Arborization can be performed through:
Increase in the amount of neurotransmitters
Increased connections from the pre-synaptic neuron
Increased connections from the post-synaptic neuron
BOTH
What is De-arborization?
The loss of connections
Also known as pruning
De-arborization occurs for a few reasons:
Natural development
Loss of represented structures
Loss of a skill
Brain insult or infarction
Synapse formation timeline:
36 weeks gestation to 2 years
Synapse pruning timeline:
4 years to 6 years
What are the 4 types of learning?
Hebbian learning
Retrograde signaling
Mirror Neuron signaling
Anti-Hebbian learning
What is Hebbian learning?
Neurons that fire together, wire together
Pre-synaptic neuron strengthens connection
What is Retrograde signaling?
Neurons surrounding the pre-synaptic neuron get stronger with the post-synaptic neuron
Increased neurotransmitters or Nitrous Oxide
What is Mirror Neuron signaling?
Neurons that fire during active and observation of activity
Increases connectivity and lateralization
What is Anti-Hebbian learning?
The post-synaptic neuron mediates the connection
Mediates the response when two types of inputs may enter the cell
Thought to occur in cerebellum
What are the principles of Neuroplasticity?
Use it or lose it
Specificity of practice
Intensity matters
Time matters
Transference
Use it and improve it
Repetitions or dosage matters
Salience matters
Age matters
Interference
Use it or lose it =
Plasticity is always occurring
The brain will take over different regions if lost or unused
Is the old phrase “Pick it back up like riding a bike true”?
Time is key
In primate experiments:
> A digit was amputated
> The brain lost representation
> The brain grew the surrounding representation
Use it and improve it =
This makes sense
The use of a skill improves the acquisition of the task
Certain types of settings or specific circumstances can increase the acquisition of skills
Specificity of practice/Transference =
Training is usually task specific
It’s very hard to improve one thing and it carry over to another skill UNLESS the skills are linked
Complex may improve simple
Like training strengthens like
> Strengthen one limb may help the other
> Performing task and watching may help (mirror neurons)
Repetitions or dosage matters =
Dr. Lang (Wash U. St. Louis)
Dosage is extremely important
~1,000-10,000 repetitions to relearn and master a skill
Under-dosing patient’s is a systemic problem
Intensity matters =
Can be identified as:
> Power
> Time to completion
> Obstacle avoidance
> Increased speed of movement
> Target distance
> Variability of support
Time Matters =
Usually the easiest time to affect change after a neurological insult, <6 months
Too early can cause problems because the person needs to start to heal
However, people can still regain tasks years after insult
Salience matters =
One of the most important parts
Person must be engaged in the activity
If you find something the person likes, they are more likely to attend to the task and continue with it
Increases belief in the themselves AND you
Age matters =
Younger tends to be easier
Healthy older adults can learn to
Declining in cognition or extreme advanced age may play a role (but not always)
Interference =
Some plasticity may interact and impede other plasticity
Learning a secondary task may initial impede performance on primary task
Other factors for plasticity =
Experience with tasks
Mood and willingness to engage
Sleep or lack of
Fitness
Pharmaceuticals
Underlying disease or comorbidities
