Visual Pathways Flashcards
apperceptive agnosia
perceptual deficit (distinction between shapes is difficult)
associative agnosia
can describe but can’t assign any meaning to objects (able to recognize simple shapes and copy complex shapes but are unable to recognize what an object is)
object agnosia
lesions on left side (can still recognize an object using non-visual cues)
prosopagnosia
inability to recognize faces
alexia without agraphia
can write but can’t read
acrhomatopsia
inability to recognize color (damage to fusiform gyrus)
balint syndrone
loss of voluntary eye movement (parieto-occipital junction)
asimultagnosia
inability to understand visual objects
scotoma
a circumscribed region of visual loss
homonymous defect
a visual field defect in the SAME region of both eyes
refractive error
indistinct vision improved by corrective lenses
photopsias
bright, unformed flashes, streaks, or balls of light
phosphenes
photopsias produced by retinal shear or optic nerve disease
entopic phenomena
seeing structures in one’s own eye
illusions
distortion or misinterpretation of visual perception
hallucination
perception of something that is NOT present
function of the retinohypothalamic tract; what is the nucleus projecting to this tract
biological clock (provides information regarding external cyclical changes in the day to our internal clock), functions in circadian rhythms. nucleus is suprachiasmatic nuc.
where are the retinal projections for the pupillary light reflex ?
pretectal region
projections from the retina to the superior colliculus function in
visual (visual tracking), somatic, and auditory information and directs the head and eyes towards the stimuli
the superior colliculus and the frontal eye fields controls what ?
saccadic eye movements
where does the superior colliculus project to
eye movement regions in the MIDBRAIN; tectospinal tract (head and neck) and the tectopontine (cerebellum)
damage to optic chiasma often results in
bitemporal hemianopia
retrochiasmal lesions often cause
homonymous vision field defects
lesion of the optic tracts often result in
contralateral homonymous hemianopia
temporal lobe lesions cause
pie in the sky vision
parietal lobe lesions cause
pie in the floor vision
lesions of the entire optic radiation results in
contralateral homonymous hemianopia
lesions in the upper bank of the calcarine fissure cause
contralateral inferior quadrantnaopia
lesions in the lower bank of the calcarine fissure causes
contralateral superior quadrantanopia
damage to the entire visual cortex results in
contralateral homonymous hemianopia
