Chapter 23: Wiring the Brain Flashcards
In which three stages do neuronal structures develope?
Cell proliferation
Cell migration
Cell differntiation
What is meant by cell differentiation?
The process in which a cell takes on the appearance and characteristics of a neuron.
What are neuroblasts?
Immature Neurons
What is the extracellular matrix?
Space between cells (can contain proteins, if appropiate cell growth occurs)
To which kind of molecules is fasciculation due?
Cell-adhesion molecules.
Name an example for a chemoattractant.
Netrin.
What is a chemorepellent? Name an example.
A diffusable molecule that chases axons away.
Slit.
What does the chemoaffinity hypothesis say?
Chemical Markers on growing axons are matched with compelmentary chemical markers on their targets to establish precise connections.
Cell death reflects competition for what?
Trophic factors
What was the first trophic factor to be identified?
Nerve Growth Factor.
What is apoptpsis?
The systematic disassembly of the neuron.
What is the synaptic capacity of a neuron?
The finite number of synapses a neuron can recieve on its dendrites and soma.
Synaptic rearrangement is the final step of address selection. It occurs as a consequence of…..
neural acitivity and synaptic transmission
What are the two simple rules for synaptic modification?
- neurons that fire together wire together
2. neurons that fire out of sync lose their link
Explain the 5 Positions in cell proliferation
- A cell in the ventricular zone extends a process that reaches upward toward the pia
- The nucleus of the cell migrates upward from the ventricular surface towrd the pial surface
- The nucleus containing two complete copies of the genetic instructions settles back to the ventricular surface
- The cell retracts its arm from the pial surface
- The cell divides in two
Wich kind of cell division predomintes the early the development of neurons?
Vertical cleavage
Later in development horizontal cleavage is the rule.
Neuroblasts destined to bevome the adult cortex migrate through the subplate to form another cell layer called…?
cortical plate
Explain the inside-out developement of the cortex.
The first cells to migrate to the cortical plate are those that form the subplate. As these differntiate intoneurons the neuroblasts destined to become layer VI cells migrate past and collect in the cortical plate. This process repeats until all layers of the cortex have differentiated. The subplate neurons then disappear.
Name the three phases of how axons find their appropiate target
pathway selection, target selection and address selection
The growing tip of a neurite is called?
growth cone
What do filopodia do?
Probe the environment and direct the growth of the axon toward attractive cues
synaptic rearrangement is the final step of…?
address selection
Results indicate that a consequence of strong NMDA receptor activation is a strengthening of synaptic transmission…called?
Long-term potentiation
