Neuroanatomy and Physiology of Vision Flashcards
Which laminae of the lateral geniculate ganglion carry information from the contralateral retina?
1, 4, 6
What Brodmann areas do the:
1) Primary visual cortex
2) Secondary visual cortices
correspond to?
Primary: Brodmann area 17
Secondary: Brodmann areas 18 and 19
In the optic radiation, do the nerve fibres from the peripheral retina pass peripherally or centrally?
Peripherally
In the optic radiation, what information is carried by:
- The temporal loop (Meyer’s loop)
- The parietal loop (Baum’s loop)?
Temporal loop: Information from inferior quadrant of retina
Parietal loop: Information from superior quadrant of retina
In the primary visual cortex, is the macula represented more anteriorly or more posteriorly?
More posteriorly
What is the length of the intracranial portion of the optic nerve and what is its blood supply?
10mm
Supplied by the ophthalmic nerve and pial branches of the hypophyseal artery
What are the dimensions of the optic chiasm and what is its blood supply?
4 x 8 x 12mm
Supplied by surrounding arteries esp. the internal carotid and superior hypophyseal artery
What is the blood supply of the optic tract?
Anterior choroidal artery and posterior communicating artery
Posterior cerebral artery runs below and parallel to it
Where do the fibres of the optic tract synapse?
Lateral bundle (90%) --> lateral geniculate body --> conscious vision Medial bundle (10%) --> other subcortical nuclei particularly the superior colliculus, pretectal and suprachiasmatic (hypothalamic) nuclei
What is the blood supply of the lateral geniculate body?
Anterior choroidal and posterior cerebral artery
What is the blood supply of the optic radiations?
Anterior choroidal, lateral striate (from MCA)
PCA
What is the blood supply of the visual cortex?
PCA (calcarine artery) and posterior anastomoses with MCA
Do the veins of the orbit contain valves?
No
Name four sinuses which communicate directly with the cavernous sinus.
Contralateral cavernous sinus
Superior petrosal sinus (to transverse sinus)
Inferior petrosal sinus (to internal jugular)
Sphenoparietal sinus
What are the three roots of the ciliary ganglion?
Sensory: short ciliary –> nasociliary (trigeminal)
Sympathetic: from internal carotid plexus
Parasympathetic (myelinated): Preganglionic from Edinger-Westphal nucleus
Where is the ciliary ganglion located?
1cm anterior to the annulus of Zinn
Lateral to the ophthalmic artery
Between the optic nerve and lateral rectus
Which layer of the primary visual cortex projects to the superior colliculus?
Layer V
Which layer of the primary visual cortex receives the myelinated nerve fibres from the lateral geniculate? What anatomical feature is associated with this?
Layer IV
White striae of Gennari
Where is the superior hemiretina represented in the lateral geniculate nucleus?
Medially
Describe the layers of the primary visual cortex.
6 layers
Retinotopic organisation in dominance columns
Layer 2 and 3: project to secondary visual cortex. Layer 2 projects to contralateral visual cortex via corpus callosum
Layer 4: receives afferents from LGN (stellate cells)
Layer 5: projects to superior colliculus
Layer 6: projects back to LGN
Does the sympathetic second order neuron leave the spinal cord via the anterior or posterior ramus?
Anterior ramus
What do the superior and inferior salivatory nuclei supply?
Inferior salivatory nucleus: Parotid gland
Superior: Lacrimal, submandibular and sublingual gland
Are ocular dominance columns present for the entire visual field?
No, the temporal crescent does not have a contralateral dominance column and is represented only ipsilaterally in the visual cortex
Which is the part of the extrastriate cortex responsible for processing colour vision?
V4
What are the dorsal and ventral streams of information for the extrastriate cortex?
Dorsal: Motion processing and binocular depth perception
Ventral (temporal): Recognition of form and colour
