studying the brain

Question 1

Disadvantages of light microscopes

Answer 1

Slices must be thin for light to penetrate
Must be solid to be sliced (water must be removed)
Absolute limit of resolution due to light interference (single point of light turns into a distribution)

Question 2

Types of patch clamp recording

Answer 2

Used to study individual channels
Cell-attached recording (mild suction to membrane)
Whole-cell recording (strong pulse of suction to break membrane so cytoplasm within pipette interior)
Inside-out recording: inside of cell membrane broken off & expose to outside environment
Outside-out recording: retract pipette & membrane breaks then seals back together with extracellular side of membrane facing outward

Question 3

Electroencephalogram

Answer 3

Uses electrodes on scalp to detect synchronisation of neural activity (states of consciousness)
Asynchronous when awake, different patterns when asleep

Non-invasive but has poor spatial resolution

Question 4

CAT scans (computer assisted tomography)

Answer 4

Use x-ray, and then computers to determine areas that absorbed x-ray less (bone mainly absorbs x-rays)

Question 5

PET Scans

Answer 5

Inject radioactive sugar (or neurotransmitter) that emit positrons. When positrons collide with electrons they emit photons (gamma rays) which are detected by the scanner.
This measures areas of brain activity by showing where glucose (or neurotransmitters) are.
By comparing the difference between a control and experimental condition the difference in brain activity can be seen.

Question 6

MRI

Answer 6

Magnetic resonance imaging.
T1-weighted MRI enhances the signal of the fatty tissue and suppresses the signal of the water. T2-weighted MRI enhances the signal of the water.

Question 6

fMRI

Answer 6

Measures brain activity through differences in hemoglobins magnetic properties when it is carrying oxygen vs when it isnt. This allows oxygenation of different areas of brain to be measured.
Active areas are OVERsupplied with blood (more oxygenated hemoglobin present) so will be slightly more magnetic

Question 7

what is a golgi stain and what does it do

Answer 7

silver staining technique that randomly stains a limited number of cells
Allowes neurons to be seen (since there is very little extracellular space between neurons)

Question 8

what does a nissi stain do

Answer 8

stains only cell body

Question 9

MEG

Answer 9

Magnetoencephalography measures the magnetic fields produced by your brain’s electrical currents (shows brain activity at high temporal resolution)

Question 10

Spatial resoltion of PET, CAT and MRI

Answer 10

PET is lowest, then MRI, then CAT is the highest