Wiring Flashcards
These function to “sniff” out the environment as a neuron grows.
Growth cones
These 2 structures are specialized sensors on the ends of developing neurons.
Lamellipodia and filipodia at the tips of growth cones
True or False. Growth cones tunnel their way through the terrain at a constant rate and speed.
False. As they reach certain landmarks, they change their shape and speed.
What happens once a growth cone reaches their final destination?
Differentiates and develops a presynaptic terminal
What molecule forms the meshwork of lamellapodia and filipodia in growth cones?
F-actin
These cells serve as landmarks at critical decision points in pathways.
Guidepost cells
What are the 2 ways in which guidepost cells direct growing axons?
Diffusible molecules
Cell surface molecules
Which cells interact with growth cones on growing axons?
Guidepost cells
These cells are crucial in the layout of the developing cortex and hippocampus. What type are they? What cells do they help?
Cajal-Retzius cells
Guidepost cell
Pyramidal neurons
How to Cajal-Retzius cells help pyramidal neurons reach their targets in cortex?
Secrete reelin
These cells in the developing nervous system are the FIRST to set up pathways.
Pioneer neurons
These are cells which latch onto a previously laid out trail and form fascicles.
Follower neurons
Which type of neuron has more filipodia- pioneer neurons or follower neurons?
Pioneer neurons
These are pioneer neurons that also transmit sensory information from periphery to the CNS during development.
Rohon-Beard neurons
Which cells act as primary sensory cells in developing nervous system? Mature nervous system?
Rohon-Beard neurons
Dorsal root ganglia cells
Cajal-Retzius cells are an example of which 2 types of neurons?
Guidepost cells
Pioneer neurons
How do pyramidal neurons get into each layer of the cortex?
Pioneer Cajal-Retzius neurons pave pathways and end up in Layer 1 (marginal zone). As pyramidal neurons develop, their growth cones extend along previously paved paths and move along radial glia toward the CR guidepost cells in Layer 1.
What is the fate of Cajal-Retzius cells?
Eventually they die
Chemical molecules can guide developing axons. In what 2 ways?
Secreted molecules as local or long distance cues
Tethered or membrane-associated molecules as short-distance cues
These 3 molecules are part of the ECM and interact with what receptor on developing axons?
Laminin
Collagen
Fibronectin
Integrins
How do developing axons recognize “other” and retract, or “self/same” and grow?
CAMs and cadherins
How do our brains replicate the maps we sense in the environment and maintain their integrity in the brain?
Series of overlaying gradients
What cells see the environment and relay that information to the brain?
Retinal ganglion cells
How to retinal ganglion cell axons identify the correct regional post-synaptic cells while retaining the visual map?
Multiple gradients of ephrin/Eph signaling
What is the benefit to using gradients of soluble factors and their receptors to make maps within the brain?
Can use a limited number of gene products and still get vast uniqueness
What 2 molecule/receptor pairs are crucial in mediating decussation pathways?
Robo/Slit
Netrin/DCC
In mature neurons, axons end in what? In developing neurons, axons end in what?
Mature- presynaptic terminals
Developing- growth cone
