OCCTH 585 Neuro Exam Study Set | Questions
with Complete Answers
What is collateral sprouting? - ✔✔when neurons sprout new synapses on bare
dendrites (either after pruning of dead synapses or less used working ones) leading the
cell to become more responsive to those new inputs
What can lead to collateral sprouting? - ✔✔more stimulation; higher representation
is driven by high rates of APs
What are the 6 mechanisms of collateral sprouting? - ✔✔- growth of new bits
- requires time
- fill vacancy OR push less used synapses out of the way
- activity dependent
- produces functional changes
Do neurons have to be close to the "free real estate" in order to make new collaterals?
Do they need to already be involved with it? - ✔✔no, the closest ones will usually get
there first, but the axons can grow out 1-2cm to form a connection (any further = stuff
in the way, would take too long and die); no
What signals to other neurons that there is space to form new collaterals and guides
them to it? - ✔✔neurotrophin (released by dendritic spines through APs)
What are chemoattractants? - ✔✔neurotrophins and other chemical signals that
signal to a neuron to grow their collaterals in that direction
,What are chemorepellants? - ✔✔chemical signals that signal to a neuron to grow
their collaterals away from that direction
What structures release chemoattractants and chemorepellants? - ✔✔guide cells
What is a growth cone? - ✔✔a specialized structure at the end of the axon that has
filopodia that branch out in multiple directions to look for chemoattractive and
chemorepellant signals
Are neurons always responsive to guidance molecules? - ✔✔no, they are time-locked
based on the developmental clock of the embryo; some guidance molecules can be both
a chemoattractant and a chemorepellant depending on the embryo's current stage of
development
A large chemorepellant signal can lead to ____ ____ ____; exposure can also signal
____________________ - ✔✔growth cone collapse; growth of filipodia off growth of
different spots of the neuron
Where are new neurons produced? (3) - ✔✔- subventricular zone (olfactory)
- dentrate gyrus of hippocampus (memory)
- Cerebral cortex
What are neurons and neurogenesis' roles in learning and memory? (3) - ✔✔-
undergo synaptic plasticity to retain memory
- can become "locked" for longterm memory
- can be replaced to allow new learning
___-___% of neurons in the hippocampus are replaced _____ - ✔✔20-25%; monthly
, What types of cells can stem cells turn into? - ✔✔- oligodendrocyte
- astrocyte
- neuron
What things determine the type of cell that stem cells differentiate into? (2) - ✔✔-
level of hormones (estrogen increases, glucocorticoids decrease)
- environmental factors (in CNS, most often are astrocytes; neurons survive longer in
enriched environment)
What barriers do we face in attempting to direct stem cells to produce neurons needed
to repair injuries? (6) - ✔✔- nervous system laid out first in embryos; difficult to build
around everything else in adults
- difficult to replicate static environment needed for neurons to be generated
- difficult to get cells to go to the repair location (no guide cells)
- migration and differentiation occur simultaneously
- don't integrate well and will eventually die
- if stem cells are poorly activated, a tumor can be created
What is different about mature neurons vs embryonic neurons? - ✔✔- many cues no
longer produced
- cells, especially neurons, are no longer responsive
- guide cells no longer exist
What 7 things occur in the nervous system following an injury? - ✔✔- terminal
degeneration
- Wallerian degeneration
with Complete Answers
What is collateral sprouting? - ✔✔when neurons sprout new synapses on bare
dendrites (either after pruning of dead synapses or less used working ones) leading the
cell to become more responsive to those new inputs
What can lead to collateral sprouting? - ✔✔more stimulation; higher representation
is driven by high rates of APs
What are the 6 mechanisms of collateral sprouting? - ✔✔- growth of new bits
- requires time
- fill vacancy OR push less used synapses out of the way
- activity dependent
- produces functional changes
Do neurons have to be close to the "free real estate" in order to make new collaterals?
Do they need to already be involved with it? - ✔✔no, the closest ones will usually get
there first, but the axons can grow out 1-2cm to form a connection (any further = stuff
in the way, would take too long and die); no
What signals to other neurons that there is space to form new collaterals and guides
them to it? - ✔✔neurotrophin (released by dendritic spines through APs)
What are chemoattractants? - ✔✔neurotrophins and other chemical signals that
signal to a neuron to grow their collaterals in that direction
,What are chemorepellants? - ✔✔chemical signals that signal to a neuron to grow
their collaterals away from that direction
What structures release chemoattractants and chemorepellants? - ✔✔guide cells
What is a growth cone? - ✔✔a specialized structure at the end of the axon that has
filopodia that branch out in multiple directions to look for chemoattractive and
chemorepellant signals
Are neurons always responsive to guidance molecules? - ✔✔no, they are time-locked
based on the developmental clock of the embryo; some guidance molecules can be both
a chemoattractant and a chemorepellant depending on the embryo's current stage of
development
A large chemorepellant signal can lead to ____ ____ ____; exposure can also signal
____________________ - ✔✔growth cone collapse; growth of filipodia off growth of
different spots of the neuron
Where are new neurons produced? (3) - ✔✔- subventricular zone (olfactory)
- dentrate gyrus of hippocampus (memory)
- Cerebral cortex
What are neurons and neurogenesis' roles in learning and memory? (3) - ✔✔-
undergo synaptic plasticity to retain memory
- can become "locked" for longterm memory
- can be replaced to allow new learning
___-___% of neurons in the hippocampus are replaced _____ - ✔✔20-25%; monthly
, What types of cells can stem cells turn into? - ✔✔- oligodendrocyte
- astrocyte
- neuron
What things determine the type of cell that stem cells differentiate into? (2) - ✔✔-
level of hormones (estrogen increases, glucocorticoids decrease)
- environmental factors (in CNS, most often are astrocytes; neurons survive longer in
enriched environment)
What barriers do we face in attempting to direct stem cells to produce neurons needed
to repair injuries? (6) - ✔✔- nervous system laid out first in embryos; difficult to build
around everything else in adults
- difficult to replicate static environment needed for neurons to be generated
- difficult to get cells to go to the repair location (no guide cells)
- migration and differentiation occur simultaneously
- don't integrate well and will eventually die
- if stem cells are poorly activated, a tumor can be created
What is different about mature neurons vs embryonic neurons? - ✔✔- many cues no
longer produced
- cells, especially neurons, are no longer responsive
- guide cells no longer exist
What 7 things occur in the nervous system following an injury? - ✔✔- terminal
degeneration
- Wallerian degeneration
