Cerebral Cortex

Question 1

Explain the 3 types of white matter in the cerebral cortex

Answer 1

1. Association fibres: connect areas within the same hemispheres
2. Commisural fibres: connect the two hemispheres (eg corpus callasom)
3. Projection fibres: connect the cortex with lower brain structures (thalamus)

Question 2

Describe the arrangement of the grey corticol layer

Answer 2

organised into 3-6 corticol layers each corticol laminae in the neocortex has functional characteristics and anatomical features.

Layers 1-3: mainly cortico-corticol connections
Layer 4: input from thalamus
Layers 5-6: connections with sub corticol, Brainstem and spinal cord.

Question 3

Describe the different lobes and their roles

Answer 3

1. Primary cortices: function predictable, organised topographically, left-right symmetry
2. Association cortices: function less predictable, not organised topographically, left-right symmetry weak/absent.

Occipital - visual, parietal - spacial map, temporal - language and memory, frontal - planning and judgment

Question 4

Describe the lesions of visual association cortex, frontal lobe, parietal cortex and temporal cortex.

Answer 4

Lesion of visual association: specifically fusiform gyrus can result in the inability to recognise familiar faces (prosopragnosiac)

Lesion of frontal lobe: characterised by lack of planning, behaviour becomes disorganised, attention spam and concentration diminishes, self control is diminished - aggressive behaviour and sexual inappropriate

Lesion of parietal cortex: posterior association cortex creates a spacial map of the body in surroundings from multi-modality, information (map unable to read etc), injury may cause apraxia and hemispatial neglect

Lesion of temporal cortex: loss of recognition, failure to understand, language, object recognition and if hippocampus then memory diminished

Question 5

Describe the hemispheric specialisation and what happens when you remove the corpus callosum

Answer 5

Right hemisphere: artistic and creative
Left hemisphere: local and scientific

Callosum taken can draw but can’t see

Question 6

How do you test the functions of the cerebral cortex

Answer 6

1. Tractography
2. TMS
3. Brain stimulation
4. PET
5. fMRIB