Introduction to clinical neuroscience

Question 1

What is the dura and what does it contain?

Answer 1

Dura is the bag that surrounds the whole brain and contains CSF and the brain itself

Question 2

What does CSF act as and what can it provide?

Answer 2

CSF acts as a conduit for clearing out toxins and can also provide nutrients for the brain as well as a cushion for the brain

Question 3

What supplies the brain for energy?

Answer 3

Arterial system supplies the brain for energy

Question 4

What are grey matter?

Answer 4

astrocytes, glia and neurons are grey matter

Question 5

What is white matter?

Answer 5

White matter is all the bits of connectivity between the grey matter

Question 6

What does a typical brain cell have?

Answer 6

Typical brain cell has:

• A cell body
• Dendrites
• long axon

Question 7

How are signals transmitted through brain cells?

Answer 7

Dendrites receive signals from other neurons and these signals get processed in the cell body and then a signal is transmitted down the axon to other cells via dendrites

Question 8

What is a glioblastoma?

Answer 8

A highly infiltrate brain tumour

Question 9

When does a hemorrhagic stroke occur and what does it cause?

Answer 9

• Its when blood vessels are blocked

- Causes localised damage

Question 10

What happens in hippocampal sclerosis and what can it cause?

Answer 10

• Structural change occurs

- Causes seizures

Question 11

Where do the effects of alzheimer’s start?

Answer 11

Starts at the hippocampus

Question 12

What do x-rays pass through and not pass through and what does this allow?

Answer 12

Passes through air but not bone therefore allows imaging of bone

Question 13

What does it mean when signals are bright or dark in a x-ray CT?

Answer 13

• If signals are bright, it shows strong attenuation of the x-rays
• If the signals are dark, it means x-rays can go through fairly easily

Question 14

How is an image produced for a MRI?

Answer 14

• Water have hydrogen atoms which have a proton
• Radiofrequency pulse put in which interacts with protons and these protons generate a signal which are picked up by radiofrequency coils giving us the image

Question 15

What does signal intensity increase with in T2w MRI?

Answer 15

Signal intensity increases with increased water content

Question 16

What leads to an increased T2?

Answer 16

Increased tissue water and loss of cellular structure all lead to an increased T2

Question 17

What resolution does T1w MRI imaging have?

Answer 17

Has 1mm spatial resolution

Question 18

What can you view in T1w MRI imaging?

Answer 18

• Degenerative change
• Developmental abnormalities
• Disease specific changes

Question 19

Why is the T1 is WM

Answer 19

• In grey matter there’s water in both intra and extracellular compartment and has relatively free motion
• In white matter approximately 50% of the tissue volume is accounted for by myelin structures. The protons of the CH3 in myelin and H20 in the axon create signalling for white matter
• Hence T1 of WM

Question 20

What are white matter tracts?

Answer 20

-Long myelinated axons that connect different parts of the brain

Question 21

What do white matter tracts have making them efficient?

Answer 21

White matter tracts have myelin sheaths that allows efficient conduction of signals

Question 22

What happens in multiple sclerosis to the myelin sheath?

Answer 22

In multiple sclerosis, the myelin sheath degrades effecting signals in different parts of the brain

Question 23

What present in the centre of the white matter tracts and what do they contain?

Answer 23

Microtubules and microfilaments which contain water

Question 24

What’s the direction of the white matter pathway?

Answer 24

Where there is the maximum diffusion of water, that’s the direction of the white matter pathway

Question 25

What TR is used in 3D angiography of the brain?

Answer 25

Very short TR of about 10ms used

Question 26

What type of signal does inflowing blood provide in a 3D angiography of the brain?

Answer 26

Inflowing blood provides a high signal against a darker background tissue signal

Question 27

What does increased extraction of glucose and O2 in bold fMRI lead to?

Answer 27

Increased glucose and O2 extraction leads to increased blood flow which leads to reduced Hb and so a MRI signal increases

Question 28

What does PET enable?

Answer 28

Enables to image particular chemicals

Question 29

Steps involved in a PET scan

Answer 29

• A radioactive nucleus decays releasing a positron and combine with electron releasing 2 gamma rays at 90 degrees
• These gamma rays are detected and then provide an image