Lecture 22- Studying neuronal function

Question 1

What is neuroinformatics?

Answer 1

-what information about the brain should be collected and interrelated -what can we measure (spatial and temporal resolution)

Question 2

What are the nine areas of information sources in neuroinformatics?

Answer 2

1.Morphology 2. Location 3. Connectivity 4. Output neurochemistry 5. Input neurochemistry 6. Electrical behaviour 7. Homologies of other brains 8. Ontogeny 9. Functional data

Question 3

What information does location (neuroinformatics) consist of?

Answer 3

-shape, projections, branching patterns, soma shape

Question 4

What information does connectivity (neuroinformatics) consist of?

Answer 4

-inputs and outputs: size, location, type

Question 5

What information does output neurochemistry (neuroinformatics) consist of?

Answer 5

-primary and secondary neurotransmitters

Question 6

What information does input neurochemistry (neuroinformatics) consist of?

Answer 6

-receptor subtypes, 2nd messenger system/ interactions

Question 7

What information does electrical behaviour (neuroinformatics) consist of?

Answer 7

-distribution of channels and pumps

Question 8

What information does ontogeny (neuroinformatics) consist of?

Answer 8

-history of gene expression, migration and environmental interaction

Question 9

What information does functional data (neuroinformatics) consist of?

Answer 9

-effects of lesions, results of modeling, experiments

Question 10

What are the two main types of neuronal cells in the brain in terms of structure?

Answer 10

-pyramidal (longer, fewer branches) -stellate (highly branching, more condensed)

Question 11

What does the Brodman’s cortical map show?

Answer 11

map based on subtle differences in neuron types

Question 12

What techniques can you use to see a neuron?

Answer 12

• eye
• light microscope
• electron microscope

Question 13

What can you resolve with an eye?

Answer 13

-man height, hand finger -cannot see cells (about 10x smaller than our resolution)

Question 14

What can you resolve with a light microscope?

Answer 14

-thickness of hair -cell -cellular components (such as bacterium) -limited by the wavelength of light (200nm)

Question 15

What can you resolve with an electron microscope?

Answer 15

-molecular scale -virus -macromolecule, small molecule all the way to individual atoms

Question 16

What are we actually looking at when using a light microscope?

Answer 16

• dead tissue, slice, it is fixed and only spatial
• want refractive index like glass so you can see
• must fix it
• thinly sliced etc. shine light from below= is refracted by the specimen and collected in the lens
• must collect as much light as possible so you can actually see it (otherwise can’t)

Question 17

What is spatial resolution of light microscopes governed by?

Answer 17

-Abbe limit -cannot resolve anything below 200nm -spatial resolution is governed by the refractive index, the wavelength of the light and how much light you can capture -there is a limit to how much resolution a light microscope can achieve

Question 18

How does fluorescence come into microscopy?

Answer 18

if sth giving off light then you can collect the light

• so then you can see thing smaller than the resolution of the microscope
• all the red dots= are synapses
• you stain sth, put fluorescent substance in
• so with light microscopes could estimate number of synapses
• when fluorescent thing put in

Question 19

What is the GFP?

Answer 19

-green fluorescent protein -can insert it into cells which then express it and can see!

Question 20

How did people overcome the Abbe limit?

Answer 20

-super resolution microscopy, got around the Abbe limit of light microscope limit -illuminate the sample and make it sharper -can see individual molecule s (normally cannot see anything smaller than wavelength of light= 200nm) ,molecules about 12nm

Question 21

What resolution do we need at the cellular membrane?

Answer 21

we need the cell membrane level resolution as that is where all the stuff happens -need fine spatial resolution -need fine temporal resolution as well as it happens quickly the change (milliseconds)

Question 22

What is the patch clamp electrode tip?

Answer 22

-electrode and its tip is so sharp you cannot see it, at the end has a little hole -makes the resolution of microscopy better

Question 23

What are the three ways of using the pipette with the hole to measure activity of a cell?

Answer 23

-can look at individual ion channels which is important as it is the basis of excitability thus communication in the nervous system

Question 24

What is this?

Answer 24

-