Cerebral Cortex Flashcards
What does grey matter consist of?
- Nerve cell bodies
What does white matter consist of?
Axons and connections
1) How does DTI work and what is it useful for?
2) How is it used in cancer patients?
1)
- Diffuse Tensor Imaging - MR modality that looks for alignment of water molecules, and coincident alignment activity - therefore a good way of looking at functional intracortical connectivity
2)
- Because it measure intracortical connectivity and function, it can be used in cancer patients to measure interruption to the brain’s activity
What are the 3 types of cerebral white matter fibres / connections?
- Association - connect areas within the same hemisphere - local circuitry
- Commisural - connect left hemisphere to right hemisphere
- Projection fibres - connect cortex with lower brain structures e.g. thalamus, brain stem and spinal cord. Long projection pathways such as motor pathways
1) How many cortical layers are there in the neocortex?
2) How many cortical layers are there in the archicortex?
1) 6
2) 3
Describe the characteristic functional and anatomical features of the cortical layers of the neocortex
- LAYER 1 - mainly neuropils (unmyelinated axons i.e. few cell bodies)
- LAYERS 2 + 3 - pyramidal neurones with corticocortical connections
- LAYER 4 - rich in stellate neurones with locally branching axons. In primary sensory cortices, this layer recieves input from the thalamus (the thalamus being the major sensory relay from the periphery)
- LAYERS 5 + 6 - pyramidal neurones which leave the cortex to other subcortical structures such as the brainstem and spinal cord
How does the layered arrangement of the visual cortex differ to that of the rest of the neocortex, and thus what name arises from this difference?
- Another ‘wet’ layer added to the normal 6 layers
- Therefore we call it the striate cortex
What does it mean to say there is columnar distribution in the cortex anatomically and functionally?
- Outside of the laminar, layered structure of the cortex, between neurones in the same layer, there may be sections with more dense vertical connections, forming the basis of topographical arrangement into layers
- Neurones of similar function are often arranged within the same column
Amongst either primary or association cortices, which of these has left-right symmetry and which does not / has it but weakly?
- Primary cortices has left-right symmetry
- Association cortices have weak / absent left-right symmetry
Describe the anatomical location of the primary somatosensory cortex including which lobe it is found in
- Found in the post-central gyrus in the parietal lobe
1) What is the primary function of the posterior parietal association cortex?
2) What symptoms might you get from injury to the posterior parietal association cortex?
1)
- Creates spatial map of body in surroundings, from multi-modality information
2)
- Disorientation
- Inability to read maps
- Apraxia
In the primary visual cortex, form & colour in vision is analysed along the ….. ….. ; spatial relationships & movement along the ….. …..
In the primary visual cortex, form & colour is analysed along the ventral stream; spatial relationships & movement along the dorsal stream
Describe the anatomical location of the auditory cortex including which lobe it is found in
- In the superior temporal gyrus in the temporal lobe
What may injury lead to in the temporal cortex?
- Agnosia
- Receptive aphasia
