Lecture 22- Studying neuronal function Flashcards
What is neuroinformatics?
-what information about the brain should be collected and interrelated -what can we measure (spatial and temporal resolution)
What are the nine areas of information sources in neuroinformatics?
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
What information does location (neuroinformatics) consist of?
-shape, projections, branching patterns, soma shape
What information does connectivity (neuroinformatics) consist of?
-inputs and outputs: size, location, type
What information does output neurochemistry (neuroinformatics) consist of?
-primary and secondary neurotransmitters
What information does input neurochemistry (neuroinformatics) consist of?
-receptor subtypes, 2nd messenger system/ interactions
What information does electrical behaviour (neuroinformatics) consist of?
-distribution of channels and pumps
What information does ontogeny (neuroinformatics) consist of?
-history of gene expression, migration and environmental interaction
What information does functional data (neuroinformatics) consist of?
-effects of lesions, results of modeling, experiments
What are the two main types of neuronal cells in the brain in terms of structure?
-pyramidal (longer, fewer branches) -stellate (highly branching, more condensed)
What does the Brodman’s cortical map show?
map based on subtle differences in neuron types
What techniques can you use to see a neuron?
- eye
- light microscope
- electron microscope
What can you resolve with an eye?
-man height, hand finger -cannot see cells (about 10x smaller than our resolution)
What can you resolve with a light microscope?
-thickness of hair -cell -cellular components (such as bacterium) -limited by the wavelength of light (200nm)
What can you resolve with an electron microscope?
-molecular scale -virus -macromolecule, small molecule all the way to individual atoms
What are we actually looking at when using a light microscope?
- 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)
What is spatial resolution of light microscopes governed by?
-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
How does fluorescence come into microscopy?
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
What is the GFP?
-green fluorescent protein -can insert it into cells which then express it and can see!
How did people overcome the Abbe limit?
-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
What resolution do we need at the cellular membrane?
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)
What is the patch clamp electrode tip?
-electrode and its tip is so sharp you cannot see it, at the end has a little hole -makes the resolution of microscopy better
What are the three ways of using the pipette with the hole to measure activity of a cell?
-can look at individual ion channels which is important as it is the basis of excitability thus communication in the nervous system
What is this?
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