cerebral cortex

Question 1

how thick is the cerebral cortex and how many neurons are within the cortex

Answer 1

2-4 mm thick (grey matter)

approximately 10-15 billion cells

Question 2

what is the name of the primitive cortex

Answer 2

allocortex and has <6 layers

Question 3

the neocortex

Answer 3

is the post-primative cortex and has 6 layers

Question 4

what are the names of the 6 layers of the neocortex

Answer 4

the first two layers (molecular and external granular) are collectively called the supragranular cortex
the second two layers (external pyramidal and internal granular) are collectively called the granular layer
the third bi-layer (internal pyramidal and mutliform) is collectively called the infragranular layer

Question 5

the cortical layers that have output to the association and other cortical area are

Answer 5

supragranular and layer III

Question 6

input from the thalamus and other cortical areas occurs in which layer of the neocortex

Answer 6

layer IV (4)

Question 7

output from the neocortex to the basal ganglia, brainstem, spinal cord occurs in which layer

Answer 7

layer V (5)

Question 8

the final layer of the neocortex is called multiform and project cortical output to which location?

Answer 8

the thalamus

Question 9

Brodman devised the cytoarchitectual map of the neocortex, Brodman area 4 and 3,2,1 respresent?

Answer 9

4 = M1 (primary motor cortex)
3,2,1 = primary sensory cortex

Question 10

Primary cortical areas control

Answer 10

simple movement and sensation

Question 11

Association cortices

Answer 11

perform higher order processing, deficits of which lead to complex phenomenon (alien hands)

Question 12

The primary visual cortex

Answer 12

receives visual information

Question 13

The superior and lateral visual association areas help process which aspects of vision

Answer 13

the superior (parieto-occiptal area) - analyses spatial infromation and movements (the where association cortex)

the lateral (occipito-temporal area) - analyses the colour and form of visual information (the what association cortex)

Question 14

What are the three main types of white matter pathways?

Answer 14

1. association fibres (one cortical region to another)
2. commisural fibres (cross the corpus callosum - interhemispheric communication of cortices)
3. projection fibres (project out of the brain)

Question 15

What are the main cerebral functions of the following brain areas?
frontal
temporal
occiptal
parietal
limbic

Answer 15

frontal - movement (RIO = restraint, initiative and order ie complex cognitive (personality) functions)
parietal - sensation
temporal - hearing and memory
occiptial - sight/vision
limbic - emotions, drive

Question 16

What are some notable features of cortical disease?

Answer 16

• presentations are complex, they are not purely motor or purely sensory
• the deficits cause impaired interpretation of stimuli
• there is asymmetry with the hemispheres

Question 17

in 90% of right handed people, and 70% of left handed people

Answer 17

the left hemisphere will dominate for language

the right hemisphere will dominate for attention and visual spatial processing

Question 18

Hemispheric preference for language, and visual-spatial processing is not apparent till which age of life?

Answer 18

3-4 years of age

Question 19

the prefrontal cortex has two main divisions (or areas)

Answer 19

dorsolateral (superior) and orbitomedial (inferior)

the dorsolateral is involved in executive functions

the orbitomedial is involved in impulse control, personality and mood

the premotor cortex has the greatest amount of post-natal brain development than any other brain region

Question 20

In most people right and left handed people attention is commonly located in which hemisphere

Answer 20

the right

Question 21

Parietal neglect syndrome

Answer 21

is where a person will fail to recognise the contralateral side of the body (visual field included)

Question 22

Cortical syndromes

Answer 22

aphasia - difficulty speaking within intact motor function (dysarthria = abnormal motor function)

apraxia - cannot carry out a task with verbal command

cortical deafness - aware of sound, but not able to interpret sound

cortical blindness - unaware of visual loss

prospagnosia - unable to recognise faces

Question 23

Gerstman’s

Answer 23

• agraphia
• acalculia
• R-L disorientation (differentiate R and L sides of body)
• finger agnosia (name of identify fingers)

caused by a non-dominant parietal lobe lesion

Question 24

de’ja’vu, lip smacking, weakness and dizziness with a preceding metallic taste

Answer 24

are signs of a temporal epilepsy - could suspect a hippocampal lesion

Question 25

Brocas area is….

Answer 25

is in the dominant language hemisphere within the lateral frontal lobe

involved in expressive speech

lesion or infarcts lead to expressive aphasia or dysphasia

people have non-fluent speech and are frustrated

Question 26

Wernickes area is….

Answer 26

is in the dominant language hemisphere within the lateral temporo-parieto-occipital lobe

involved in receptive speech

lesion or infarcts lead to receptive aphasia or dysphasia

people have fluent speech which is non-sensicle and lacks comprehension

Question 27

Brocas and Wernickes area communicate with each other by which white matter fibres

Answer 27

arcuate fasciculus

Question 28

Lesions of the arcuate fasisculus cause

Answer 28

conduction aphasia in which repetition of words is impaired but fluency and comprehension are preserved