WEEK 4 + 5 - VISUAL PERCEPTION AND DISORDERS Flashcards
(29 cards)
order of anatomy of visual pathway
retina, optic nerve, optic chiasm, optic tract, lateral geniculate nucleus (LGN), optic radiation, primary visual cortex (V1)
if ONE eye is damaged
unilateral field loss
if the OUTER corners of eyes are damaged
bitemporal hemianopsia
if ONE inner and ONE outer eye is damaged
homonymous hemianopsia
V1 upper visual field
ventral V1 and LGN
lower visual field
dorsal V1 and LGN
fovea
posterior V1
periphery
anterior V1
left visual field
right LGN
right visual field
left LGN
Two visual stream hypothesis (TVSH)
model that proposes proposes two distinct neural pathways in the brain that process visual information
dorsal stream
vision to direct ACTIONS
ventral stream
vision to PERCEIVE environment
visual agnosia
impairments in deriving meaning to visually presented, despite intact sensory and low-level vision, and normal language and semantic function
apperceptive visual agnosia
failure to process visual elements together for perception (ie. unable to identify, copy or match drawings to what they see)
associative visual agnosia
perception is stripped of meaning (CANNOT visually identify what they are seeing)
simultanagnosia
Inability to appreciate the overall meaning from complex picture or scene (ie. Cookie Theft Task)
hemi-attention
one modality affected, most commonly vision
hemi-neglect
more than one sensory modality is affected
prosopagnosia
visual impairment in recognising faces
topographical agnosia
visual impairment for recognising landmarks
visual form agnosia
visual impairment for recognising shape/form
Visual Object and Space Perception Battery (VOSP)
an initial screening test (shape detection), to assess whether the visual and sensorial capacity of patients are sufficient to complete the other subtests
Patient DF
developed visual agnosia after being poisoned - formed basis of TVSH model
