Cerebral Cortex

Question 1

what does the cerebral cortex contains ? and how thick is it?

Answer 1

it covers the entrie surface of the brain. it is about 2-3mm thick.

Together with the deep nuclei, it contains grey matter.

organised into lobes and has folds called gyri

Question 2

Describe the microscopic organsiation of the cerebral cortex?

Answer 2

it is organised into layers and columns

Question 3

draw out and label the layers of the cerebral cortex

Answer 3

Question 4

Draw out and label the columns of the cerebral cortex

Answer 4

Question 5

Describe how Bordmann classifed the 52 different regions of the brain

Answer 5

Cytoarchitecture.

This is bascially cell size, spacing or packing density and layers.

these cytoarchitecture relates to different functions

Question 6

what are the functions of the frontal lobe?

Answer 6

Question 7

what are the functions of the parietal lobe?

Answer 7

• sensation - pain and touch
• sensory aspect of language
• spatial orientation and self perception

Question 8

What is the function of the occipital lobe?

Answer 8

Processing visual information

Question 9

what are the functions of the temporal lobe?

Answer 9

Question 10

what does the limbic lobe entail and what does it do?

Answer 10

it contains the :

• cingulate gyrus
• Amygdala
• Hippocampus
• Mammillary body

it’s functions are: learning, memroy, emotion, motivation and reward

Question 11

what is the insular cortex and what does it do

Answer 11

it lies deep top the lateral fissure.

it is concerend with:

• interoception
• visual-vestibular intergation
• auditory processes
• visceral sensations
• autonomic control

Question 12

what are the arrows poitning out and desciribe the features of the cells.

Answer 12

Grey matter- umyelinated cell bodies and glial cells. around 85 billions

Whtie matter- myelinated axons arranged in tracts

Question 13

What are the 3 different types of white matter tracts and what do they each do?

Answer 13

they connect cortical areas of the brain.

Question 14

What are the 2 different types of association fibres?

Answer 14

Short fibres (u-fibres)- connects adjacent cortical regions.

green in image.

Long fibres - other colours in image

Question 15

The image below show the short and long association fibres.

label the long fibres and give function.

Answer 15

• Pink - the SUPERIOR LONGITUDOINAL FASCICULUS: it connects frontal lobe to occipital lobe.
• purple- ARCUATE FASCICULUS: connects frontal lobe with temporal lobe (broca’s area to wernicke)
• blue- INFERIOR LONGITUDINAL fasciculus- connects temporal lobe to occipital lobe
• orange- UNCINATE fasciculus- connects anterior frontal lobe to temporal lobe.

Question 16

what are the 2 commisural fibres of the brain

Answer 16

Question 17

what are the types of projection fibres?

Answer 17

Afferent- towards cortex

Efferent- away from cortex

Question 18

Deeper to the cortex what do the projection fibres radiate as? and hwere do they converge?

Answer 18

Thye radiate as the corona radiata

They converge through the internal capsule between thalamus and basal ganglia

Question 19

What are the differences between primary and association cortices?

Answer 19

Question 20

label the respective areas in the frontal lobe

Answer 20

Question 21

What are the respective functions of the priamry motor cortex, premotor area and supplementary area of the frontal lobe?

Answer 21

Question 22

what are the functions of the primary somatosensory cortex and somatosensory association

Answer 22

Primary- it processes somatic sensations in the body arising from receptors

Assocation- interprets significance of sensory information ie. recognising information/thing placed in hands when eye is closed. it is also responsible for self awareness and personal space awareness.

Question 23

What are the functions of the primary visual cortex and association cortex

Answer 23

Primary- processes visual information.

Association- interprets and gives meaning to visual input

Question 24

What are the functions of the primary auditory cortex and assocation cortex?

Answer 24

Question 25

What are the functions of the prefrontal cortex?

Answer 25

* attention * planning * adjusting social behaviour * personality erxpression * decision making

Question 26

What are the respective functions of the Broca's and Wernicke's area?

Answer 26

Broca- since it's close to the motor area. it is responsible for PRODUCTION of speech Wernicke's area- understanding language, whether spoken or written

Question 27

What are the implications of frontal lobe lesions ?

Answer 27

Changes in personality Inappropriate behaviour

Question 28

Whar are the implications of Parietal lobe lesions

Answer 28

***Contralateral neglect*** of self and other world class (extrapersonal space). ie. if lesion is ont he right, he'd lack awareness the left side of the body and left side of the world

Question 29

What are the implications of lateral and medial lesiosn to temporal lobe

Answer 29

Lateral- agnosia- inabiltiiy to recognise things although you can still see it. Medial- anteroregrade amnesia; can't form NEW memories.

Question 30

What are the implications to lesions in Broca's and Wernickes area?

Answer 30

Broca- Expressive aphasia Wernicke- Receptive aphasia

Question 31

What are the implications of lesions to primary visual cortex and visual association cortex

Answer 31

Primary- blindness in corresponding visual field Association- deficits in interpretation of visual information. e.g facial blindness (can't learn new faces) or prosopagnosia (can't recognsise familiar faces)

Question 32

In assesing cortical function, what are the 2 imaging methods and contrast them

Answer 32

**PET**- injects redioactive glucose (risky) and then tell them to do tasks and watch the brain area that lights up. it checks **blood flow** to particular brain region. **fMRI**- action is taking and then it measures blood oxygen in brain region. ie. proportion of oxy: deoxy blood. THEY BOTH HAVE DIFFERENT SPATIAL (detailed info you can see) AND TEMPORAL RESOLUTION (lowest amount of time)

Question 33

What are the types of encephalography used in assessing cortical function

Answer 33

**EEG**- MEASURES ELECTRIC signals produced by brain **MEG**- measures magnetic signals produced by the brain. it produces event related potentials

Question 34

Why is a flipped chessboard used as a stimulus to visually evoke potentials and give the signifcance oif the numbers and letters on the graph

Answer 34

Flipped chessboard is used as it produces 100s of stimulus for the brain so that the potential can be picked up. P₅₀ - postive but it shows NEGATIVE deflection 50ms after stimulus

Question 35

One of the ways of assesing cortical function is through brain stimulation. TMS can be used to stimulate the brain. Explain what this entails and give any clinical relevance for it

Answer 35

TMS uses electromagnetic induction to induce current in brain to bring about a function in the body as it stimulates neurons. Hence can be used ton assess fucntional intergroty of neural circuits. MAY be used clinically for: * epilpesy * depression * tinnitus * migraine

Question 36

what is tDCS? give relevant details

Answer 36

Transcranial direct current stimulation it uses low direct current over scalp to stimulate or inhibit neuronal firing rates. can be used to inhibit chronic pain/ major depressive disorders or epilepsy

Question 37

what is DTI and what does it entail

Answer 37

Diffusor tensor imaging - based on diffusion of water molecules and hence can check the activity of the neuronal tracts There is also DTI with tactography

Question 38

Explain how somatosensory evoked potenitals work in encephalography

Answer 38

Stimulus put in hand and then electrodes placed at diffferent points in body from spinal cord up until crown of head. Potentials are measured sequentially along the somatosensory pathways

Question 39

Draw out the electrodes needed for encephalography

Answer 39