Classes 7 and 8 - Occipital lobe and vision disorders Flashcards
What are two sulci in the occipital lobe?
Parieto-occipital sulcus and calcarine sulcus
What visual cortices are on the lingual gyrus?
V2 and primary visual cortex
What visual cortices are on the fusiform gyrus?
V4
What are different names for V1?
BA17, striate cortex, primary visual cortex
What is the prestriate cortex?
V2
What are V3, V4 and V5?
Extrastriate cortices
What is the purpose of V4?
Perception of color
What is a general pathway of the visual cortex?
LGN > primary cortex > secondary cortex > dorsal, ventral or STS stream
What do the ventral, dorsal and STS streams do?
Identify the object, visual guidance of movements, visuospatial functions respectively
What is the purpose of V5?
To detect motion
What is the purpose of the STS?
To detect shape
What are some hemisphere asymmetry features in the brain?
Right hemisphere is good for mental rotation. Left temporal-occipital region might be a part of image generation
What is blindsight?
You are legally blind, but can still detect things in front of you to a certain extent
What are the two visual pathways?
Geniculostriate (conscious vision) pathway and tectopulvinar (detecting and attending to visual stimuli) pathway
What is monocular blindness and how does it happen?
Loss of vision in one eye. Caused by lesion to optic nerve or retina.
What is bitemporal hemianopia and how does it happen?
Loss of vision in peripheral fields. Caused by lesion to optic chiasm
What is nasal hemianopia and how does it happen?
Loss of vision in one nasal field. Caused by lesion to the lateral chiasm (outside tracts)
What is homonymous hemianopia and how does it happen?
Blindness in one visual field. Caused by lesion in LGN, optic tract or V1
What is macular sparing and how does it happen?
Sparing of the central visual field. Caused by lesion in the occipital lobe
What is quadrantanopia and how does it happen?
Loss of vision in one quarter of the fovea. Caused by occipital lobe lesion
What are scotomas and how do they happen?
Small blind spots. Caused by small lesions of the occipital lobe
The loss of color vision is called what? Where is the lesion?
Achromotosia. Lesion in V4
The loss of movement vision is called what? Where is the lesion?
Akineopsia. Lesion in V5
What is the deficiency of being able to recognize objects called? Where is the lesion?
Visual object agnosia. Lesion in occipital temporal junction
What is prosopagnosia? Where is the lesion?
Inability to recognize faces. Lesion in the fusiform face area
What is visuospatial agnosia? Where is the damage?
Inability to position self to environment and identify position of objects with each other. Lesion in the parietal occipital junction
What is optic ataxia? Where is the damage?
Loss of visual guidance of movement… cannot grab things. Lesion in dorsal stream.
What are the two forms of simultagnosia? How do they work?
Ventral simultagnosia (can see multiple objects, recognition is piecemeal) Dorsal simultagnosia (can only see one object at a time, objects in movement are harder to see) Happens from bilateral parieto-occipital lesions
What is Balint syndrome? How does it happen?
Optic ataxia, occulomotor apraxia, simultagnosia
What is apperceptive agnosia? Where is the damage?
Inability to perceive the structure of objects. Bilateral damage to lateral parts of occipital lobes.
What is associative agnosia? Where is the damage?
Can perceive/draw the object but cannot identify them. Results from anterior temporal lobe damage.
