NEURO LEC 21: NEUROPLASTICITY Flashcards by Chavez Girls

Motor learning vs performance

Learning- relatively permanent change

Preformance- temporary change observed during practice

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Neuroplasticity - what 3 mechanisms does it include

habituation and sensitization
learning and memory
healing from injury

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3 types of nondeclarative/implicit memory

non-associative
associative
procedural learning

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non associative implicit learning

single stimulus repeatedly

habituation and sensitization

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Habituation is a simple form of neuroplasticity where you have learned ____________

supression of non-noxious stimuli

Note: you can take a tolerance break and then the response will be re-elicited to same stimuli

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Habituation is due to decreased synaptic activity between….

Sensory neurons and interneurons/motor neurons

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Short term habituation is due to ________ changes

-reduction of neurotransmitter

-less Ca2

presynaptic

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Longterm habituation is due to ________ changes and structural changes

post synaptic

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Sensitization is caused by strenghtening the response to a stimuli that is _________________

preceded by a noxious stimuli

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T or F. Sensitization is a more complex process than habituation

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Habituation can be due to altered

decreased synapses long ter, or decrease Ca+ and NT release from presynaptic neurons for short term

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In long term sensitization there are changes in:

Altered strength of existing synapses

synthesis of new proteins

modification of synapses

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implicit ASSOCIATIVE learning

predicting relationships

classical and operant conditioning

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Classical conditioning vs operant conditioning

classical- 1 stimulus to another

Operant- behavior to consequences

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Long term association is the result of

causes new protein synthesis with formation of new synapses between the neurons

requires 2 neurons to fire simultaneously

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Classical conditioning example

dog hears bell and gets food

bell -> dog salivates

note: timing between conditioned stimulus and unconditioned response has to be fast.

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Trial and error learning, is onvolved with ______ conditioning and is shaped by

operant

internal thoughts and motivation

requires close temporal association due to simular neuro processes as classical conditioning

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For implicit procedural learning the movement must be ___________ by the learner through trial and error and _____________

Performed

within the context of the skills and in typical environment

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procedural learning occurs in specific areas of the….

frontal & parietal cortices, basal ganglia, and cerbellum

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implicit procedural learning definition

Learning and execution of motor and nondeclarative (dont need consious recall) cognitive tasks, especially w/ sequences

example: skills and habits

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Explicit declarative memory

requires attn, consciousness, info that can be expressed (semantic or episodic)

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How does declarative memory work? what structural process occur

Long term potentiation - weak input fires with strong output, facilitating weak input and strengthening synapse

Long term depression - low or weak activity at a synapse weakens the synapse (receptors decrease)

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What parts of the brain are responsible for explicit learning?

prefrontal cortex

cingulate gyrus

Caudate

Medial temporal lobes

hippocampus

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long term potentiation (LTP) requires the firing of both ________ and ___________ cells at the same time

pre and post synaptic

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What is longterm potentiation (LTP)?

when weak and strong input arrive at the same time at the post synaptic dendrite, and the **weak one will be facilitated** due to association with the stronger stimulus *similar to sensitization*

Short term potentiation has ___________ only whereas long term potentiation causes _____________

functional changes only protein synthesis for structural changes

Long term depression is similar to ________ long term potentiation is similar to ______________-

habituation sensitization

What are the three key principles of LTP?

associativity, cooperativity, specificity

What is associativity?

When **contributing fibers** and **post synaptic cells** work together to give a **stronger** input (weak input becomes stronger due to traveling the same route as a stronger input) neurons that fire together wire together!

What is cooperativity?

Requires > 1 neuron working together all the neurons working together converge on the same synapse and combine their inputs to become stronger.

**Specificity**: Example:_____________

Only synapses that are highly active will exhibit long term potentiation Selective memory, use it or lose it

What is meant by experience dependent neuroplasticity?

LTP and LTD lots of brain areas are are active when learning a new task but they decrease with repetition Repeated stimulation or pairing of pre and post-synaptic stimulation and activation of new proteins enhances or inhibits new synapses (requires protein synthesis) rewiring

When learning a new task, many brain areas are active, with repetition......

fewer areas are active becoming more streamlined as the skill developed

T or F, myelin also demonstrates experience dependent neuroplasticity

True helps facilitate faster, smoother signals

Enhanced motor skill development seen in patients after _______

sleep! sleep locks in what you learn

T/F: implicit and explicit memory overlap

T implicit memory can shift to explicit (doing something automatically and then being able to explain what you did later) explicit and shift to implicit (skill becoming automatic that was originally conscious)

Sensorimotor cortices are active when learning a skill. But with practice, there is an increase of activity in the ________ pathways, which can end up bypassing sensorimotor cortices and go straight to the motor cortex (more efficient paths with repetition)

thalamocorticol pathways

Why are parallel pathways important?

aif in efficiency and redundancy, makes movement fast, smoother and automatic important incase of injury

Stages of motor learning _________ -> ___________ -> _____________

cognitive -> associative -> autonomous Note: as you progress the level of attention required goes down

what is the cognitive phase?

learner concerned with understanding the nature of the task and developing strategies, high level of cognitive activity, many errors

In the **early cognitive phase** of motor learning, you're reliant on ______________ from motor performance,

sensory feedback

Early cognitive phases experience an _________ and then a _____ in *dorsolateral prefronal cortex, sensorimotor cortices, parietal areas, and cerebellum* activity

increase decrease

When do you have larger improvements? Cognitive phase or associative phase?

cognitive phase associative phase - slower improvements

**Associative phase**: __________ are less active than initial stage increase in activity in the ____________ Less motor planning and executive functioning needed

motor and sensory areas dentate, thalamus, putamen

Which phase includes: Trial and error period trying new strategies refining skills preformance less variable

associative phase

During the **autonomous** stage the ________ remains active but ________ decrease activity

primary motor cortex cortical association areas

What areas increase in activity as a task becomes more automatic?

Basal ganglia Thalamus Cerebellar Nuclei

What motor learning phase is characterized by Minimal attention required stable preformance error detection present increased accuracy, smoothness, and speed

Autonomous stage

How does motor learning abilities change with aging?

- older adults need more practice for automatic skills - older adults require more brain activity for automatic skills - again can impact dual task capabilities

Most brain damage after stroke or trauma comes from secondary effects of __________, vs the initial acute injury

excitotoxicity

What is excitotoxicity

excessive **glutamate** released from hypoxic cells that **destroys** post-synaptic neurons

During excitotoxicity, glutamate binds to receptors and increases intracellular _______, this causes more _____ to exit the cell. Due to this, more glycolysis is required to give sufficient energy -> more lactic acid -> acidosis -> breaks down cell

CA+ K+

(excitotoxicity) Heightened glycolysis in cells causes excess _________ which reduces intracellular pH causing acidosis which breaks down the cell membrane

lactic acid

(excitotoxicity) CA+ stimulates protein enzymes that release _______, and make oxygen free radicals along with excessive NO, causing more cell damage

arachodonic acid note: also water influx ocurs causing cellular edema

Right after axon is severed in an injury ______ leaks out of both ends and segments retract away from eachother

cytoplasm

Distal segments of an axon (when severed), start ____________ process with axon degeneration and myelin sheath pulling away from axon

wallerian degeneration

What kind of cells clean up an axonal injury?

**Glial cells** clean up area of axonal injury

During axonal injury, the distal segment undergoes Wallerian degenerates while the associated cell body degenerates through central ___________

**Chromatolysis** which may lead to cell death note: Post synaptic cells may also die if most input is lost

Collateral sprouting vs regenerative sprouting

Collateral- **neighbor** axons take over work of damaged one regenerative: damaged one sends **new** sprout to original target

What is the speed of axonal growth after injury?

1mm/day or 1 inch a month

Nerve growth factor is produced by ________ cells and then they form a sheath guiding the sprouting axon to its target cell

schwann cells

Exercise starting at day _____ facilitates neuron regrowth and muscular reinnervation

What is synkinesis?

**Regrowth** causes innervation of **inappropriate target**, leads to temporary movement abnormalities

Most CNS damage after an injury occurs due to __________

secondary cascading events (metabolic changes like Ca+ influx, swelling and breaking, chromotolysis and Wallerian dengernation)

After an injury: Proximal axons experience ______ Distal axons experience ________

Chromatolysis Wallerian degeneration

A traumatic brain injury can cause widespread tearing or stretching/disconnecting , this is called.....

DAI Diffuse axonal injury

Glial scars (damaged glial cells) can block regrowth and release _______

NOGO Neurite outgrowth inhibitor NOGO is expressed in oligodendicytes and not schwann cells

So in the PNS axon injuries can regenerate, what about the CNS?

no, you dont have Schwann cells, plus you have glial cells, scaring and oligodendrocytes releasing NOGO

Cell body death vs Axonal injury?

Cell body death always causes neuron death axonal injury not always

after injury, what allows recovery of synaptic effectiveness of nerves?

resolution of edema compressing on axons allows resumption of normal cell function

What is denervation hypersensitivity

Synaptic change after injury Increased post-synpatic receptors available to accept Neurotransmitters released from neighboring neurons (increased sensitivity to neurotransmitters)

What is synaptic hypereffectiveness

Synaptic change after injury: When pre-synaptic terminals are damaged, remaining post-synaptic branches receive all neurotransmitter that would normally be shared. (Remaining synapses now receive too mcuh input )

What are 4 synaptic changes after injury?

1. Recovery of effectiveness 2. Denervation hypersensitivity 3. Synaptic hypereffectiveness 4. Unmasking/disinhibition of silent synapses

What is the use it or lose it principle? Use it and improve it principle?

Failure to drive specific brain functons lead to functional degradation Opposite

What is the specificity princple?

The nature of training dictates the nature of neuroplasticity

Repetition matters principle

induction of neuroplasticity requires sufficient repetition

Intensity matters principle

neuroplasticity requires sufficient training intensity

Time matters principle

Different forms of plasticity happen at different times in training

salience matters principle

the training must be salient to induce plasticity (pt must be aware and engaged)

Age matters principle:

training induced neuroplasticity occurs more in younger brains

transference principle

plasticity in response to one training can enhance simular behavior

interference principle:

plasticity due to one experience can inferfere with acquisition of other behaviors