Regeneration / Plasticity of CNS Flashcards
What is a critical period an alignment of?
The intrinsic maturation programs and environmental input
What is activity dependent competition?
It is the idea that activity refines the stabilization of synaptic connections
How does maturation affect proneuronal innervation of muscle fibers?
Over time, immature muscle fibers that are innervated by many neurons prunes into a mature muscle fiber innervated by a single neuron
How was neural pruning exemplified with AChR blocking?
AChR blockade was applied to an area of a neuromuscular junction, and the axon branch withdrew from the nonfunctioning receptors which were lost
When does vision segregation begin to occur?
In the womb
What is the reason for vision segregation before the cortex in the LGN?
Spontaneous activity in ganglion cells
What is a Hebbian modification? How does it contribute to the lateralization of the LGN?
It occurs when synapses from two input neurons fire at the same time, and strengthens the synapses with the LGN. Conversely, it weakens crossing over neurons when both neurons form one eye fire and target the correct synapse. This leads to a lack of crossing over.
What happens to the percentage of neurons in layer 3 of the visual cortex after a monocular deprivation?
There is a shift in the ocular dominance group to the open eye, and a blocking of the ocular dominance areas of the closed eye.
The cutting of which axons leads to the inability of the visual cortex to switch ocular dominance groups?
The cutting of the ACh and NE pathways
What happens to monocular deprivation with age?
As aging occurs, the percentage of susceptibility decreases i.e. there is a critical period for monocular deprivation adaptation
What is the remedy for a lazy eye?
Patching
When can we see neural plasticity through environment influences?
Amputation or injury
When are brain wires places/pruned?
Placed before birth, and pruned during infancy
What are the two developmental systems with strong critical periods?
The visual system and the sensorimotor system
When are phantom limb sensations sometimes stimulated? Why?
Phantom limb sensations can be stimulated when a somatotopically bordering area is stimulated, because the remapping/reorganization has not yet fully occurred.
What are the two determinants of neural plasticity?
Genetic connectivity, and experience-dependent reorganization
What are the only two areas of the brain where neurogenesis in adulthood happens?
- The subventricular zone (SVZ) - lateral ventricle
- The sub granular zone (SGZ) - hippocampus
Where in the SVZ is adult neurogenesis observed?
Migration in the rostral migratory system, and genesis in the olfactory bulb
Where in the SGZ is adult neurogenesis observed?
In the granule layer of the dentate gyrus
How does SVZ neurogenesis occur?
New neuroblasts are formed in the stem cells in the lateral ventricle, which migrate down to the olfactory bulb where the neurons are formed.
What is a type 1 cell?
A neural stem cell
What is a type 2 cell?
A proliferating cell
How long does it take for an adult stem cell to differentiate and then survive and fully develop?
Differentiates at 3 days and then reaches final stage at or past 4 weeks
What are the stages of development for a new adult neurogenesis cell? (how long does this take from genesis)
Proliferation(3 days), differentiation(1w), survival (4w+)
