Lecture 2 - Neuroanatomy

Question 1

What % of brain cells are neurons?

Answer 1

10%

Question 2

How many neurons approx do we have and how many do they connect to in turn?

Answer 2

Approx 100 billion that connect to 10,000 each

Question 3

How often do we lose cortical neurons ?

Answer 3

1 per second

Question 4

What is white matter made up of?where can it be found?

Answer 4

Myelinated axons and supporting glia cells

Found underneath the cerebral cortex grey matter

Question 5

If you have the side view of the brain, how would you describe the front and the back, what terms would you use?

Answer 5

Front : anterior (so that would be prefrontal cortex)

Back : posterior ( so that would be occipital cortex)

Question 6

Side view of the brain, what terms do you use to describe the top and bottom ?

Answer 6

Superior : top ( so that would be near the parietal )

Inferior : bottom ( so that would be like temporal/ basic brain structures)

Question 7

How do you describe the navigational line from the corpus calloused out to the outer part of the brain?
if you were looking at it sideways it would be the axis that comes out towards you

Answer 7

Medial to lateral

Question 8

If you are shown a side on slice of the brain, what would you call that?

Answer 8

Sagittal slice

Question 9

If you were shown a slice of the brain of someone who was looking you in the eyes what would you call it?

Answer 9

Coronal view

Question 10

If you were shown brain slices from the top of the head down to the spine. What would you call it ?

Answer 10

Axial view

Question 11

What are the 4 main sulci?

Answer 11

Longitudinal fissure
Central sulcus
Lateral sulcus (Sylvian fissure)
Parieto-occipital sulcus

Question 12

What do these four main sulci delineate?

Answer 12

They delineate the 4 main lobes of the brain, temporal, parietal, occipital and frontal.

Question 13

Which fissure is thought to delineate v1, v2, v4?

Answer 13

Calcarine fissure

Question 14

What are the names of two big neuroanatomists?

Answer 14

Campbell

Brodmann

Question 15

What did brodmann do ?

Answer 15

Using a staining technique (Nissl stain) he looked at the cytoarchitecture of the brain and found 52 distinct areas of the brain.
He wanted to not just look at the gross anatomy of the brain but what the main gyri and sulci were comprised of

Question 16

What is laminar?

Answer 16

Laminar means layers, brodmann found 6 different layers each containing different types of neurons which were paced differently for each section of the brain.
E.g. The visual areas are very tightly packed whereas motor layers are more spread out.

Question 17

What is a fasciculus?

Answer 17

White matter fibre tract

Question 18

Is the white matter organised or just a random bunch of connections ?

Answer 18

Organised.

Can be split into 4 major tracts

Question 19

What are the 4 major white matter tracts?

Answer 19

Superior longitudinal fasciculus
Uncinate
Inferior fronto-occipital fasciculus
Cingulum

Question 20

What are the three broad categories of white matter tracts called? What do they connect?

Answer 20

Association tract - links cortical within hemisphere
Projection tract - cortical to subcortical (like cerebellum and basal ganglia)
Commissure - cortical between hemisphere

Question 21

Marner et al (2003) took a tiny portion of white matter fibres and counted the number of myelin sheaths within this section. They did this for both males and females ranging between 20 years and 100 years.
What did they find?
What did they conclude?

Answer 21

Marner et al found that as age increased the number of myelin sheaths (amount of nerve fibre per km) decreased significantly.
They concluded that anatomical fibre integrity is linked to performance on cognitive tasks like memory and therefore, that’s why as you get older your performance worsens.

Question 22

Scholz (2009) taught his participants to juggle in a 6 week programme. They had brain scans, before, after the 6 weeks and again after 6 months.
What did they find?

Answer 22

Found 6% increase in white matter health in the visuo-spatial area of the brain.
This increase remained for 6 months after the study as well.

Question 23

What is the standard brain space?

Answer 23

A technique used to compare individuals brains that will all be slightly different shapes and sizes

Question 24

Name 2 types of standard spaces

Answer 24

Talairach

MNI (Montreal neuro institute)

Question 25

How does talairach differ from MNI?

Answer 25

MNI is an average of about 152 brains, which you then use the anterior commissure as coordinates (0,0,0) and align the new brain to it.
Talairach only used on standard brain and mapped the scans brains onto it.

Question 26

Describe 5 important parts of a neuron

Answer 26

1. Dendrites - receive messages from other neurons
2. Soma - cell body, grey matter
3. Axon - transmits messages along
4. Myelin sheath - speeds up transmission, protects axon from damage, white matter
5. Nodes of ranvier - gaps in the myelin sheath, allows for passive conduction