intro to neuroscience

Question 1

CT

Answer 1

method of 2D/3D imaging measuring the X-ray attenuation through a tissue

Question 2

Magnetic Resonance Imaging (MRI)

Answer 2

2D/3D imaging by detecting signals produced by protons in water and fat molecules

Question 3

T2 MRI

Answer 3

signal intensity related to water content (signal intensity increases with increased water content)

Question 4

T1 MRI

Answer 4

signal intensity related to the differences in white and grey matter (they have different cellular structure)

Question 5

Diffusion-weighted MRI

Answer 5

microscopic diffusion of water molecules is measured (in a specific direction)

Question 6

PET

Answer 6

2D imaging based on detecting gamma rays produced by injected radiopharmaceutical

Question 7

Radiopharmaceutical

Answer 7

molecule (given either intravenously or orally) with a radioisotope attached

Question 8

what makes humans dominant species in comparison to other primates?

Answer 8

greatly developed frontal lobe

Question 9

describe the relationship between grey mass and number of neurons in the cerebral cortex for humans?

Answer 9

many more neurons per grey mass

Question 10

what is the encephalocentric theory?

Answer 10

theory the brain is the centre of sensation and understanding

Question 11

what is the cardiocentric theory?

Answer 11

theory that the heart is the centre of sensations and intelligence

Question 12

what is the dura and what is its function?

Answer 12

bag surrounding the brain that contains the CSF and brain: acts as a conduit for clearing out toxins, provides nutrients to the brain, mechanically acts as a cushion

Question 13

what cells make up the grey matter?

Answer 13

• glia
• astrocytes
• neurons

Question 14

what structures are involved in a typical brain cell?

Answer 14

• cell body
• axons
• dendrites

Question 15

what is the function of dendrites?

Answer 15

receives signals from other neurons

Question 16

what is the function of the axon?

Answer 16

axons transmit the processed signal in the cell body

Question 17

brain structure of functional localisation

Answer 17

primary somatosensory cortex

Question 18

phineas gage (significant frontal lobe damage)

Answer 18

• personality changes
• fitful
• irreverent
• impatient

Question 19

monsieur loborgne (lesion in broca’s area)

Answer 19

• only able to utter syllable: Tan Tan

- broca’s area identified to be responsible for speech

Question 20

glioblastoma

Answer 20

highly infiltrative brain tumour

Question 21

how does a CT scan work?

Answer 21

• x-ray tube rotates around the patient
• x-rays beamed through the patient
• detectors detect the x-rays on the other side
• measure the attenuation of the x-rays to lots of different tissues

Question 22

how can MRI be used to measure anatomical changes?

Answer 22

• grey and white matter proportions
• degenerative change
• developmental abnormalities
• disease-specific changes

Question 23

what is the difference between white and grey matter?

Answer 23

grey matter: inter and intra-cellular compartments have free motion
white matter: 50% of tissue volume is myelin structures

Question 24

difference in T1 of white matter and grey matter?

Answer 24

T1 of WM>GM

Question 25

How does T2 weighted MRI work?

Answer 25

• H+ atoms in HO have one proton
• the nucleus is positively charged (spins and acts as a magnet)
• this spin generates a signal because the radio frequency interacts with protons
• signal picked up by radiofrequency coils, computer processing produces an image
• therefore more water= stronger signal and structural changes in the tissue are picked up

Question 26

what is white matter?

Answer 26

wiring between the grey matter

Question 27

what is the purpose of the myelin sheath?

Answer 27

enables electrical signals to progress from one part to the other

Question 28

what happens in MS?

Answer 28

myelination is lost

Question 29

what does a bright signal mean?

Answer 29

brighter the signal, more anisotropy (shows where the white matter tracts are)

Question 30

what does a diffusion tensor MRI show?

Answer 30

coloured lines show the direction and connectivity of the corticospinal tract coming up to the core of the brain- powerful tool for understanding degenerative disease

Question 31

explain the difference between signal intensity in arterial and venous blood in the brain?

Answer 31

• arterial blood has a uniform magnetic field
• increased glucose and oxygen extraction leads to increased blood flow
• Oxy-Hb moves from arterial to venous, due to inc blood flow
• Oxygen is released in the brain and so left with deoxy-Hb in the venous circulation which is paramagnetic
• presence of paramagnetic deoxy-Hb causes a non-uniform magnetic field
• therefore there is a reduction in signal intensity
• veins have a lower signal intensity than the arteries

Question 32

how does a BOLD fMRI work?

Answer 32

blood-oxygen-level-dependent imaging: based on differing signal intensities in venous and arterial

Question 33

gross structural and pathological change

Answer 33

CT, MRI

Question 34

anatomical and developmental change

Answer 34

MRI

Question 35

metabolite levels

Answer 35

MRS

Question 36

blood flow

Answer 36

CT, PET, MRI

Question 37

metabolism

Answer 37

PET

Question 38

connectivity

Answer 38

MRI

Question 39

functionality

Answer 39

MRI, PET

Question 40

receptors

Answer 40

PET