Neuroanatomy Techniques Flashcards
What affect does formaldehyde have on brain tissue?
It fixes proteins, prevents autolysis and degeneration and makes the tissue firm
How are brains processed in order to be thinly sliced?
They are fixed in formaldehyde
How are formaldehyde fixed tissues sections?
Using a microtome, producing 10-200um thick slices
What type of sections are produced when a rotary microtome is required?
Paraffin slices of 100-200um thick
What type of machine is used to cut both living and fixed tissue?
A vibrotome (high speed vibrating razor blades)
Frozen brain sections are cut via a…?
Cryostat (5um)
An ultramictotome is used to cut what kind if tissue?
Sections embedded in epoxy resin (1-100um)
DAPI is a stain used to detect what cellular component?
DNA in living or fixed neurones
What stain is used when identifying degenerating axons in the brain?
Nauta silver stain
Nissl stain is specific to staining which cellular components?
Nuclei, RER and ribosomes surrounding the nucleus in neurones and glia (nissl bodies)
What is a drawback of using the nissl stain?
It only stains cell body components, so neurites and axons aren’t labelled
Which staining technique stains cell bodies and neurites of the neurone?
The Golgi stain using silver chromate
What are the resolution limits of both light microscopes and electron microscopes?
0.1um and 0.1nm respectively
Why can a light microscope not distinguish neurone details?
Because neurones are only spaced 0.02um apart, smaller than the light microscope resolution
What is a monochromatic beam and how is it formed?
Thin stream of electrons in an electron microscope accelerated in a vacuum and focused using metal apertures
What is immunohistochemistry?
The use of antibodies to stain and visualise proteins inside neurones
Why are antibodies sometimes combined with fluorescence in immunohistochemistry?
To allow for multiple proteins to be identified in a single tissue section
How are fluorescent tags visualised?
Applying a UV light to a microscope. Red dye emits at 570nm and green dye is 515nm
How are substances transported along axons and what is this called?
Via the neurones microtubules, this is axoplasmic transportation
Movement of substances from the soma to the axon terminal is known as…?
Anterograde transportation
Movement if substances from the axon terminal to the soma is called…?
Retrograde transportation
How axoplasmic transportation mechanisms exploited?
Radioactive amino acids are injected to trace axonal routes
What is transneural tracing?
The use of neurotropic viruses that travel intimate synaptic connections to understand brain function
