Flashcards in The Occipital Lobe Deck (19):
What is the dorsal stream?
-The where/how stream
-Visual guidance of movements
What is the ventral stream?
-The what stream
-Object perception (including colour)
What are the five categories of vision?
-Vision for action (parietal visual areas in dorsal stream; reaching, ducking, catching)
-Action for vision (visual scanning, eye movements and selective attention)
-Visual recognition (temporal lobes; object recognition)
-Visual space (parietal and temporal lobes; spatial location)
-Visual attention (selective attention)
What is monocular blindness?
-Loss of vision in one eye
-Results from destruction of retina or optic nerve
What is bitemporal hemianopia?
-Loss of vision from both temporal fields (lateral vision)
-Results from lesion to medial region of the optic chiasm
What is nasal hemianopia?
-Loss of vision of one nasal field
-Results from lesion of the lateral chiasm
What is homonymous hemianopia?
-Blindness of one entire visual field
-Results from a complete cut of the optic tract
-Damage to LGN or V1
What is macular sparing?
-Results from lesion to occipital lobe
-Sparing of central or macular region of visual field
-Differentiates lesions of optic tract or thalamus from cortical lesions
-Macular sparing occurs only after lesions to the visual cortex
What is quadrantanopia of hemianopia?
-Results from lesion to the occipital lobe
-Complete loss of vision of one-quarter or one-half of the fovea
What are field defects?
-Scotomas - small blind spots
-Results from small lesions to occipital lobe
-Visual system is good at overcoming these blind spots
What is blindsight?
-Perception of motion and location without perceiving content
What is visual form agnosia?
-Inability to recognize line drawings of objects
-Bilateral damage to LO region and tissue between parietal and occipital lobes
What is optic ataxia?
-Deficit in visually guided hand movements
-Bilateral hemorrhages in occipito-parietal regions
Prosopagnosia is caused by a lesion in which brain area?
-Right occipito-temporal lesion
Alexia is caused by a lesion in which brain area?
-Left occipito-temporal lesion
What is apperceptive agnosia?
-Deficit in ability to develop percept of an object of objects
-Can describe components of object but cannot say what the whole thing is
-Bilateral damage to lateral parts of occipital lobes
What is simultagnosia?
-Unable to perceive more than one object at a time
What is associative agnosia?
-Can perceive objects, but cannot identify them
-No memory of objects
-Lesions to anterior temporal lobes