21. Neuroplasticity & Neural Basis of Motor Learning Flashcards
neuroplasticity
the ability of neurons to alter their function, amounts and types of neurotransmitters produced, and/or structure
-involved in memory and learning
mechanisms of neuroplasticity
habituation/sensitizaton
experience-dependent plasticity: learning/memory
recovery or maladaptation after injury
learning
change in behavior that results from acquiring knowledge and practice
- process of acquisition
memory
the process by which that knowledge is encoded, stored, and later recalled/retrieved
-the product of learning and acquisition
Motor learning vs performance
Learning- relatively permanent change
Performance- temporary change observed during practice
what type of memory is closely related to the learning process?
long term memory
2 forms of long term memory
nondeclarative (implicit)
declarative (explicit)
3 types of learning involved with nondeclarative/implicit memory
non-associative
associative
procedural
non-associative learning
occurs when an animal is given a single stimulus repeatedly → nervous system learns about the characteristics of that stimulus
habituation/sensitizatoin
Habituation is a simple form of neuroplasticity where you have learned ____________
supression of non-noxious stimuli
↓ Decrease in response to a repeated, benign stimulus over time
Habituation is due to decreased synaptic activity between….
Sensory neurons and interneurons/motor neurons
Short term habituation is due to ________ changes
-reduction of neurotransmitter
-less Ca2
presynaptic
Longterm habituation is due to ________ changes and structural changes
post synaptic
Sensitization is caused by strenghtening the response to a stimuli that is _________________
preceded by a noxious stimuli
↑ Increase in response to a repeated or strong stimulu
T or F. Sensitization is a more complex process than habituation
T
Habituation can be due to altered _______ conductance or facilitating more neuro transmitter release
K+
In long term sensitization there are changes in:
Altered strength of existing synapses
synthesis of new proteins
modification of synapses
associative learning
when a person learns to predict relationships
-classical and operant conditioning
Classical conditioning vs operant conditioning
classical- 1 stimulus to another
Operant- behavior to consequences
Long term association causes new protein synthesis with formation of….
new synapses between the neurons
Classical conditioning example
dog hears bell and gets food
bell -> dog salivates
note: timing between conditioned stimulus and unconditioned response has to be fast.
operant conditioning
trial and error learning
reinforcement/punishment
Trial and error learning requires close ___________ due to simular neuro processes as classical conditioning
temporal association
Note: Trial and error learning is behavior shaped by internal thoughts and motivation
procedural learning
learning tasks that can be performed automatically without attention or conscious thought → implicit knowledge
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
procedural learning occurs in specific areas of the….
frontal & parietal cortices, basal ganglia, and cerbellum
implicit procedural learning definition
Learning and execution of motor and nondeclarative cognitive tasks, especially w/ sequences
example: skills and habits
Declarative learning requires conscious processing with end product of…
Acquiring knowledge that can be expressed explicitly/consciously
What parts of the brain are responsible for explicit learning?
Prefrontal cortex, cingulate gyrus ___________, ________, ____________
Caudate
Medial temporal lobes
hippocampus
people with lesions to ___________ have difficulty remembering factual knowledge
bilateral medial temporal lobe
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 → increase synaptic strength
similar to sensitization
long term potentiation (LTP) requires the firing of both ________ and ___________ cells at the same time
pre and post synaptic
Short term potentiation has ___________ only whereas long term potentiation causes _____________
functional changes only
protein synthesis for structural changes
long term depression
active synapse changes to silent/weak synapse by removal of post-synaptic receptors into cytoplasm → decrease synaptic strength (helpful for chronic pain)
Long term depression is similar to ________
long term potentiation is similar to ______________-
habituation
sensitization
LTP and LTD of which areas of the brain are Important for spatial memory and memories that can be verbalized
hippocampus
temporal lobe
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)
REPETITIONS
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:
Only synapses that are __________ will exhibit long term potentiation
Example:_____________
highly active
Selective memory
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
Enhanced motor skill development seen in patients after _______
sleep
______ memory and _____ memory overlap and are used in most learning activities
implicit and explicit
note: implicit and explicit memories can shift to the other kind
Motor learning:
Practice can increase activity of _______, which can activate the motor cortex, bypassing the somatosensory cortex
________ are developed aiding in efficiency and redundancy (especially important for case of injury)
thalamocortical pathways
parallel pathways
Stages of motor learning
_________ -> ___________ -> _____________
cognitive -> associative -> autonomous
Note: as you progress the level of attention required goes down
cognitive phase
learner is concerned with understanding the nature of the task and developing strategies that could be used to carry out the task
In the early cognitive phase of motor learning, you’re reliant on ______________ from motor preformance, many errors, rapid improvment
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
Trial and error period
trying new strategies
refining skills
preformance less variable
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
autonomous phase
Minimal attention required
stable preformance
error detection present
increased accuracy, smoothness, and speed
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
Healthy older adults are able to acheive new automatic motor skills but require….
significantly more practice than younger adults
Patterns of brain activities are simular in older and younger adults during skill acquisition. But Older adults need ____________ to attain simular levels of automaticity
significantly more brain activity
Aging can impact ______ capabilities since harder/longer time to reach automaticity
Dual Task
Most brain damage comes from __________, than the intial 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, 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
chromatolysis
neuron’s cell body undergoes structural changes as it attempts to recover and regenerate the damaged axon.
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 they they form a sheath guiding the sprouting axon to its target cell
schwann cells
Exercise starting at day _____ facilitates neuron regrowth and muscular reinnervation
5
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
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
is nerve growth factor located in the PNS or CNS?
PNS
Cell body death vs Axonal injury?
Cell body death always causes neuron death
axonal injury may or may not cause cell death
synaptic changes after injury
recovery of synaptic effectiveness
denervation hypersensitivity
synaptic hyper effectiveness
unmasking/disinhibition of silent synapses
recovery of synaptic effectiveness
resolution of edema compressing on axon allows resumption of normal cell function and synthesis/transport of neurotransmitters
What is denervation hypersensitivity
Increased post-synpatic receptors available to accept Neurotransmitters released from neighboring neurons (increased sensitivity to neurotransmitters)
What is synaptic hypereffectiveness
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 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
