S2 Neuroscience > Neuroplasticity > Flashcards

Neuroplasticity Flashcards

(65 cards)

Start Studying
1
Q

models of nervous system function

  • have historically influenced…
  • what are they?
A

have historically influenced ideas about the system’s ability to reorganize
Hierarchical Control Model
Distributed Systems Model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hierarchical Control Model

  • what is it?
  • 2 specific ideas
A

higher brain centers control primitive behaviors in lower brain centers
localization of function
-specific brain areas control specific functions
no regeneration in CNS because of inability of central axons to regenerate following lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

distributed systems model

  • what is it?
  • 3 specific ideas
A

numerous reciprocal connections between and within levels of CNS
information and motor commands flow in all directions
function is a cooperative effort among regions of the CNS
control site depends on the task to be executed
-voluntary movement - area 4 vs. automatic movement - area 6; both may be active

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

habituation

  • what is it
  • why does it happen
  • eventually may result in…
A

decrease in a response due to a decrease in the synaptic effectiveness (decreased neurotransmitter released from presynaptic membrame)
eventually may result in decreased number of synaptic connections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

sensitization

  • what is it
  • may involves what synapses?
A

enhancement of synaptic transmission
experience with one type of stimulus (i.e. painful) enhances responsiveness to other stimuli (i.e. nonpainful)
may involve axo-axonal synapses (presynaptic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

sensitization

-chemial reason for why it works

A

facilitating neurons, some of which are serotonergic, enhance transmitter release from the sensory neurons by increasing the amount of second messenger cAMP in the sensory neurons
these effects are short-term

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

sensitization

-with repeated exposure to stimulus, what can happen?

A

long-term changes may occur that involve the synthesis of new protein and gene activation (mRNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

long term potentiation

-what is it?

A

cellular mechanism proposed for formation or consolidation of memories through hippocampal formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

long term potentiation

  • how does it occur
  • the effects of the LTP are specific to…
A

cooperative and associative activation of numerous neurons in the hippocampal formation increases the amplitude of EPSPs (increased depolarization) on a receptive cell
the effects of the LTP are specific to those synapses that are activated by the stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

long term depression

  • what circuitry?
  • purpose
A

cerebellar cortical circuitry proposed to be responsible for motor learning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

long term depression

-essential process required for this to occur

A

the persistent desensitization of selective glutamate receptors that mediate mossy fiber –> parallel fiber –> Purkinje cell transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

long term depression

-role of climbing fibers

A

play a leading role in induction of LTD
monitor the performance of a system in which the cerebellar circuitry plays a role and informs Purkinje cells about control errors due to misperformance of the plan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

long term depression

-classic example

A

change in gain of VOR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

neuroplasticity development

-thought to serve as…

A

a process template for lateral neuroplastic changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

development: radial glial cells

- function

A

guidance system for neuronal migration in neural tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

development: process growth

- what is it

A 
the axons and dendrites extend outward from the soma, the axon first process in vivo
in vitro (petri dish), undetermined neurite outgrowth occurs until a "guiding signal" is recognized that determines axon vs. dendrite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

development: guidance of the process (axon and dendrites) formation is governed and directed by…

A

a number of external signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

development: growth cone

- importance of the enlarged tip

A

has multiple filopodia or lamellipodia

  • contain organelles and cytoskeleton necessary for growth and addition of neuron membrane as well as movement proteins
  • the membrane is rich in receptors responding to directing signals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

development: directing signals

- what are the various signals?

A

contact inhibition
growth factors
calcium
GAP 43

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

development: adhesion different dependent upon…

A

extracellular matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

contact inhibition

-can be…

A

recognition of neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

growth factors
-nerve growth factor function
what other growth factors may play a role?

A 
nerve growth factor supports and directs process outgrowth
other growth factors
-BDNF
-epidermal growth factor (EGF)
-fibroblast growth factor (FGF)
-cytokines and hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

calcium

  • function
  • how does it work?
  • too much may result in…
  • what other role of calcium is useful to remember when thinking about this concept
A

modify growth cone mitility
thought to act by facilitating depolarizing currents as the neurite grows
too much may result in hyperpolarization, effectively slowing down growth
Ca++ has a role on terminal activity specific to neurotransmitter release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

GAP 43

-found in…

A

growth cones of axons, not dendrites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
synaptogenesis and pathfinding | -contact guidance
membrane molecule mediated (neural cell adhesion molecule, laminin, neural cadherin)
26
synaptogenesis and pathfinding: chemotropism - specific to... - example - evidence has been noted in...
neurotransmitter specific, region specific example -the growth of individual neuronal cell axons in response to extra-cellular signals, which guide the developing axon to innervate the correct target tissue -evidence of chemotropism has been noted in neuronal regeneration, where chemotropic substances guide the ganglionic neurites towards the degenerated neuronal stump
27
synaptogenesis and pathfinding: galvanotropism - growth toward... - what substance is thought to be a factor in neurite outgrowth?
negative pole in voltage variable environment substance -calcium
28
synaptogenesis and pathfinding: neurotransmitter-specific | -explain
postsynaptic excitability, presynaptic site formed first then postsynaptic site modifies position by becoming localized
29
synaptogenesis and pathfinding: adjustments | -2 examples
``` apoptosis (programmed cell death) exuberant axons (multiple axons develop and then are reduced to a single functional axon) ```
30
synaptogenesis and pathfinding: competition | -types
spatial and chemospecific -functional validation of "the best suited wins" this may be spatial on any given neuron
31
synaptic changes after injury: recovery of synaptic effectiveness -neurons at site of injury may be temporarily affected by...
neurons at site of lesion may be temporarily affected by swelling, free radical presence, loss of blood supply, neurotoxic chemicals released in response to trauma
32
synaptic changes after injury: synaptic hypereffectiveness - where is the change - what happens
change in presynaptic event | -more neurotransmitter released
33
synaptic changes after injury: denervation hypersensitivity - in response to... - what happens
in response to vacated synapses, adaptive changes occur to other synapses in the area increased receptor density in postsynaptic membrane is evidenced in mammalian NS
34
synaptic changes after injury: denervation hypersensitivity - originally found in... - in denervated muscle...
originally found in PNS | in denervated muscles, Ach receptors increased in density in entire length of muscle, not just motor endplate
35
synaptic changes after injury: denervation hypersensitivity - where else can it happen apart from PNS - -in what condition - -how does it occur?
also known to happen in basal ganglia with Parkinson's disease cells in the striatum deprived of DA input from substantia nigra -some receptors will increase in density in postsynaptic membrane
36
synaptic changes after injury: unmasking of silent synapses - what are silent synapses - what happens with this unmasking - potential reason why it works
some synapses exist on dendrites that are "silent" (don't release neurotransmitter) these normally ineffective synapses become effective may consist of strengthening dormant synapses of remaining input to a cell
37
synaptic changes after injury: unmasking of silent synapses | -kitten study example
one eye of kitten was sewn shut for 4 months when the eye was opened, only 10% of the cortical cells responsed to light (normally 80% would - most cells are binocular) the remaining good eye was surgically removed -immediately 40% of the neurons in the cortex receiving connections from the previously sutured eye now responses to light -this suggests that the pathways were present but not being used
38
axon reorganization: axonal regeneration - what is it? - may connect with...
sprouts from injured axons start growing out within several days of injury may connect with nearer cell bodies, scarring a problem
39
axon reorganization: axonal regeneration - possibility in human CNS - possibility in PNS
not a strong possibility in human CNS | occurs in PNS
40
axon reorganization: axonal regeneration - rate in PNS - process is similar to...
rate of 1 mm/day scarring can still be a problem this process is similar to axon outgrowth during development using similar signals such as growth factor giudance
41
axon reorganization: collateral sprouting | -what is it?
surviving neurons that innervated the same target organ are somehow stimulated (postsynaptic hypersensitivity) to send out collateral branches from their axons to reinnervate denervated target cells
42
axon reorganization: collateral sprouting - when does it begin? - where does it occur?
begins 4-5 days post-injury | first identified in PNS, but now confirmed in CNS
43
axon reorganization: collateral sprouting | -specificity of sprouts
not randon new input closely related to original function (use of same neurotransmitter, although not necessarily same afferent system)
44
axon reorganization: collateral sprouting | -advantage and disadvantage
advantage -may prevent dendritic atrophy and maintain functional level of excitability (but not necessarily the same function) disadvantage -may create abnormal connections - SCI - may be responsible for spasticity
45
activity-dependent functional reorganization | -what are 2 ways you can change the cortical representation of digits?
amputation | apply spinning disc with sensory information to tip of finger
46
what percentage of fibers needed to be spared in a SCI to recover walking?
25%
47
propriospinal system: propriospinal neurons - what are they - what do they do? - important for...
interneurons whose cell bodies are located intrinsically in the spinal cord these neurons ascend and descend throughout the cord, and they integrate both sensory and motor information propriospinal neurons are important for synchronizing activity in spinal motor circuits
48
propriospinal system: short propriospinal neurons - span... - organization
span 6 vertebral segnents organized in columns through the spinal cord -more medial neurons innervate axial trunk muscle -more lateral neurons innervate distal limb muscles some cross, some ipsi
49
propriospinal system: long propriospinal neurons | -function
connect cervical and lumbar enlargements involved with the patterned motor activity seen in walking some cross, some ipsi
50
staggered hemisection | -what is it
researchers initially lesion one half of the spinal cord, wait a few weeks, and then lesion the other half of the spinal cord at a different level
51
staggered hemisection | -what is it
researchers initially lesion one half of the spinal cord, wait a few weeks, and then lesion the other half of the spinal cord at a different level
52
staggered hemisection | -results
following the hemisection injury to the corticospinal tract, transected fibers sprout into cervical gray matter to communicate with propriospinal interneurons, which then relay the motor command to its distal target the motor command coming from the brain can now use this new corticopropriospinal pathway to carry out its mission
53
how can the corticopropriospinal connection be enhanced
pharmacology | locomotor treadmill training
54
effect of aging on neuroplasticity | -primary thing that occurs
decrease in brain weight and volume
55
aging: what areas of the brain decrease?
frontal and temporal lobe | hippocampus and amygdala vs. primary sensory and motor regions
56
aging: what increases?
increase ventricle size
57
aging: two mechanisms
cell loss | neuronal atrophy
58
aging: axonal death | - loss of collaterals may explain...
decrease in ability to "multitask"
59
aging: effect of neuronal atrophy on excitability of neuron
decreased input - increased time for summation - increased processing time
60
what else apart from aging can lead to atrophy and cell death?
disuse
61
stem cells | -where are they present?
layer I and at other places such as the hippocampal formation
62
stem cells | -responsible for...
continued CNS mitotic growth well into our 20s
63
stem cells | -can be turned on by...
trauma such as ischemia or traumatic denervation
64
stem cells | -response to trauma
generate new neurons
65
stem cells | -the problem
as it exists now (current technology), we don't know how to "encourage" this growth in a positive way or direct migration of new cells to area of need the increase in new neuron number does not predict that axonal growth can or does occur

S2 Neuroscience (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions