Neuroanatomy Techniques

Question 0

What affect does formaldehyde have on brain tissue?

Answer 0

It fixes proteins, prevents autolysis and degeneration and makes the tissue firm

Question 1

How are brains processed in order to be thinly sliced?

Answer 1

They are fixed in formaldehyde

Question 2

How are formaldehyde fixed tissues sections?

Answer 2

Using a microtome, producing 10-200um thick slices

Question 3

What type of sections are produced when a rotary microtome is required?

Answer 3

Paraffin slices of 100-200um thick

Question 4

What type of machine is used to cut both living and fixed tissue?

Answer 4

A vibrotome (high speed vibrating razor blades)

Question 5

Frozen brain sections are cut via a…?

Answer 5

Cryostat (5um)

Question 6

An ultramictotome is used to cut what kind if tissue?

Answer 6

Sections embedded in epoxy resin (1-100um)

Question 7

DAPI is a stain used to detect what cellular component?

Answer 7

DNA in living or fixed neurones

Question 8

What stain is used when identifying degenerating axons in the brain?

Answer 8

Nauta silver stain

Question 9

Nissl stain is specific to staining which cellular components?

Answer 9

Nuclei, RER and ribosomes surrounding the nucleus in neurones and glia (nissl bodies)

Question 10

What is a drawback of using the nissl stain?

Answer 10

It only stains cell body components, so neurites and axons aren’t labelled

Question 11

Which staining technique stains cell bodies and neurites of the neurone?

Answer 11

The Golgi stain using silver chromate

Question 12

What are the resolution limits of both light microscopes and electron microscopes?

Answer 12

0.1um and 0.1nm respectively

Question 13

Why can a light microscope not distinguish neurone details?

Answer 13

Because neurones are only spaced 0.02um apart, smaller than the light microscope resolution

Question 14

What is a monochromatic beam and how is it formed?

Answer 14

Thin stream of electrons in an electron microscope accelerated in a vacuum and focused using metal apertures

Question 15

What is immunohistochemistry?

Answer 15

The use of antibodies to stain and visualise proteins inside neurones

Question 16

Why are antibodies sometimes combined with fluorescence in immunohistochemistry?

Answer 16

To allow for multiple proteins to be identified in a single tissue section

Question 17

How are fluorescent tags visualised?

Answer 17

Applying a UV light to a microscope. Red dye emits at 570nm and green dye is 515nm

Question 18

How are substances transported along axons and what is this called?

Answer 18

Via the neurones microtubules, this is axoplasmic transportation

Question 19

Movement of substances from the soma to the axon terminal is known as…?

Answer 19

Anterograde transportation

Question 20

Movement if substances from the axon terminal to the soma is called…?

Answer 20

Retrograde transportation

Question 21

How axoplasmic transportation mechanisms exploited?

Answer 21

Radioactive amino acids are injected to trace axonal routes

Question 22

What is transneural tracing?

Answer 22

The use of neurotropic viruses that travel intimate synaptic connections to understand brain function