Control Lecture 5: Visual pathways Flashcards
What are the general layers of the retina, in order from the choroid to the vitreous humour in the posterior compartment where light arrives?
Pigmented epithelium
Photoreceptors
Primary neurons
Secondary neurons
What are the primary neurons in the visual pathway?
Bipolar cells
What are the secondary neurons in the visual pathway?
Ganglion cells
What other neurological cells are present in the retina apart from bipolar and ganglion cells, and what is their function?
Interneurons
Modulate and adapt the system
Where do ganglion cells converge?
Optic disc
Why are the photoreceptors deep to the neurological cells within the retina, further from the arriving light?
Reduces the intensity of light hitting the photoreceptors
Are bipolar and ganglion cells counted as being in the CNS or PNS/
CNS
Which lobe of the brain do the tertiary neurons of the visual pathway project to?
Occipital
Which sulcus is the primary visual cortex centred around?
Calcarine
Which nucleus in the thalamus does the visual pathway pass through?
Lateral geniculate nucleus
Where does the optic nerve pass out of the skull?
Optic canal
Which meningeal layer forms the sclera of the eyeball?
Dura mater
Which meningeal space persists in the eyeball?
Subarachnoid
What does CSF buildup cause in the eyes?
Papilloedema
Where do the blood vessels of the eye radiate from?
Optic disc
Which side of the left eye detects light from the left hand side?
Nasal
Which side of the right eye detects light from the left hand side?
Temporal
Which side of the right eye will be associated with fibres in the same optic tract as fibres from the temporal side of the left eye?
Nasal
Do fibres from the nasal or the temporal side of the eye run in the contralateral optic tract?
Nasal
Do fibres from the nasal or the temporal side of the eye run in the ipsilateral optic tract?
Temporal
What do fibres travel in between the thalamus and the cerebral cortex in the visual pathway?
Optic radiations
Do fibres running in the superior trajectory to the cortext originate from the upper or lower eye?
Lower
Can the calcarine sulcus be seen in a medial or a lateral view of the brain?
Medial
What kind of fibres pass between the striate cortex and the visual association cortex?
Association
What is the cortex around the calcarine sulcus (primary visual cortex) called?
Striate cortex
Does information from the upper or the lower visual field end up at the upper bank of the calcarine sulcus?
Lower
Where does information from the macula end up in the cortex?
Occipital pole
What is the name for a localised patch of blindness?
Scotomia
What is the name for loss of half of the visual field?
Hemianopia
What is the name for loss of a quarter of the visual field?
Quadrantanopia
What is it called when visual field loss is the same on both sides?
Homonymous
What is it called when visual field loss is different on both sides?
Heteronymous
Monocular blindness. Where is the lesion?
Unilateral optic nerve
Heteronymous hemianopia. Where is the lesion?
Middle of the optic chiasma
Lesion takes out both contralateral fibres from nasal sides
Homonymous hemianopia. Where is the lesion?
Unilateral optic tract
Homonymous quadrantanopia. Where is the lesion?
Single trajectory of the optic radiations eg. inferior trajectory on left side -> upper right quadrant field loss
Homonymous hemianopia with macula sparing. Where is the lesion?
Superior and inferior trajectories on one side
Bilateral central scolomas. Where is the lesion?
Occipital pole
