Karteikarten
Visual field representation
Karten in diesem Stapel (15)
- 1In which layers of the LGN do the nasal axons of the opposite eye terminate?1, 4, 6
- 2In which layers of the LGN do the nasal axons of the opposite eye terminate?2, 3, 5
- 3What is the geniculo-cortical pathway?The pathway from the LGN to internal capsule, then optic radiations and then to V1.
- 4What problem does the inferior horn cause to the optic radiations?They obstruct the axons coming from the lateral half of the LGN (Upper visual quadrant) therefore they have to initially travel anteriorly and then loop (meyers loop) around it to join optic radiations.
- 5Why is the hemi-field map in area V1 cortex said to be inverted and distored?Because the lower visual quadrant is represented in the upper bank of calcarine sulcus whereas thte upper visual quadrant is represented in the lower bank of the calcarine sulcus. It is distorted because both banks over represent fovea & macula.
- 6What supplies blood to the axons in the 1st part of radiations after the internal capsule?Middle cerebral artery
- 7What supplies blood to the axons in the last part of radiations?Posterior cerevral artery
- 8What supplies blood to the calcarine sulcus upper & lower banks?Calcarine artery (terminal branch of PCA)
- 9What supplies blood to the occipital pole?Both calcarine artery (a terminal branch of PCA) & a terminal branch of the MCA.
- 10What 4 ways can the white matter (optic pathway and radiations) cause lesions or damage to the V1 cortex?-Prevents/ slows impulse conduction
-Infection (inflammation)
-Trauma (compression by tumors)
-Vascular lesions i.e blockage or haemorrhage - 11What 4 ways can the grey matter (LGN and V1) cause lesions or damage to the V1 cortex?-Kill cells which cannot be replaced
-Infection (inflammation)
-Trauma (compression by tumors)
-Vascular lesions i.e blockage or haemorrhage - 12What do pituitary adenomas initially compress?Axons from the nasal inferior retina at chiasm.
- 13What percentage of the retinal ganglion cells are from the fovea and macula?66-75%
- 14What happens to the fascicular organisation from the axons in the optic nerve to the axons in the optic tract?In the optic nerve, the axons are separated by connective tissue and astrocytic septa into 100 groups of fascicles with mixed parvo and magno cell axons.
In the optic tract, the axons change to non-fascicular. The parvo cell axons are deepest and magno cell axons near plial surface. - 15Why is there a change in the organisation of the parvo and magno cell axons in the optic tract?So that they are lines up ready to terminate in the different parvo and magno layers on LGN.
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- Degree Visual science Karteikarten am Visual field representation, erstellt von ghada.hamdi.1 am 27/10/2015.
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