Basics of Neurobiology (Days I and II)

Question 1

How does cargo traffic preferentially to the axon or to a dendrite?

Answer 1

1. There is a uniform orientation to microtubules in the axon (+ end out) while microtubules in dendrites have mixed orientations.
2. MAPs - microtubule associated proteins - help determine which way cargo is transported. Dendrites display MAP2 on their microtubules while axons display Tau on their microtubules.
3. Axon initial segment filter, which is a filter-like region at axon hillock that physically sorts out specific cargo. Still poorly understood.

Question 2

KB staining

Answer 2

Kluver-Barrera staining (KB): (combination of Nissl stain + Luxol-fast blue stain) Labels cell bodies and myelin.

Question 3

Nissl stain

Answer 3

Basic dye that binds to DNA and RNA

Question 4

Luxol-fast blue

Answer 4

Labels myelin

Question 5

Golgi-Cox staining

Answer 5

Chemical reaction that generates crystals which fill the entire cell. Only labels 1-3% of neurons. Reveals fine neurologic detail.

Question 6

Rabies tracing

Answer 6

Rabies virus passes retrograde from post-synaptic neuron to pre-synaptic neuron in order to spread. This is exploited in a laboratory setting to study connectivity. Most labs use a modified rabies virus that can only spread one neuron back.

Question 7

Optogenetic approaches

Answer 7

Fiber-optic cable hooked up to a mouse brain. Activates opsin molecules (light activated ion channels isolated from plankton) including ChR2 (Na+ channel, blue light) and NpHR (Cl- channel, yellow light). So, you can promote or repress transmission through specific neurons by introducing these under a certain promoter.

Question 8

Satellite Glia

Answer 8

PNS cells which sheath neuron cell bodies in PNS ganglia. Provide metabolic and structural support.