cognitive vision loss
Simultanagnosia (ventral)
(L>R) -can't see arrays of letters, only one at a time
Simultanagnosia (ventral) deficit region
(L>R) occipitoparietal region
Simultanagnosia (dorsal) deficit region
(bilateral) occipitoparietal junction
face agnosia (Prosopagnosia) CVL tests errors
(due to pFus being involved) -form -motor-free -line
face agnosia (Prosopagnosia) CVL tests failed
- face
form agnosia deficit region
-LOC (dorsal) recognizes objects -V7 (dorsal) encodes objects -IT cortex (Macaques only) extends more anterior for macaques
visual form discrimination
-NOT test memory -tests discrimination bt complex configurations -basic forms encoded by euros in LOC
face agnosia (Prosopagnosia) deficit region
-VOT (ventral occipitotemporal) -(FFA) -also lesser so: LOC, pFus
Blindsight deficit region
-area V1 -unaffected dorsal path leaves visual guidance intact(superior colliculus neurons are intact and sensitive to motion)
Simultanagnosia (dorsal)
-can recognize pieces of sense but not a whole -"not being able to see properly" -"blind and clumsy" -cannot see 2 objects in 2 locations
associative agnosia
-can recognize, no perception of meaning
Optic Aphasia
-can't name visual objects (unless verbally described or touched) -however no semantic info loss - have some degree so does;t really affect life
apperceptive agnosia
-can't perceive/recognize/discriminate stimuli
Simultanagnosia (dorsal or ventral)
-cannot get scene as a whole -VF, color, acuity intact
comprehensive trail-making test (CTMT)
-combines high order visual cognitive planning + visual spatial perception -frontal lobe processing deficit if inc time
motion agnosia
-damage to V5/MT -strobe objects in motion -rare
Optic ataxia 3 things
-hard determining orientation of objects, problems grabbing objects -poor eye mvmts -fine orientation with lines or depth perception
topographic (place) agnosia
-impaired recognition of scenes and landmarks -in convo with secondary Alzheimer's disease or other degenerative white matter disease
Cognitive vision loss tests (CVL)
-judgement line orientation -visual form discrimination -facial recognition -ruff-light trail learning test (RULIT) -motor-free visual perception test (MVPT-3) -comprehensive trail-making test (CTMT)
topographic (place) agnosia failed tests
-learn -unlikely to show errors in other tests unless extends to medial/posterior occipitotemporal
Optic Aphasia failed tests
-line -this isn't directly assessed by any CVL tests
Semantic dementia
-loss of semantic memory (face, voice, places) -preserved visual spatial cognition, episodic learning and memory (day to day), non-verbal reasoning
semantic dementia failed tests
-make -limited errors in other 5 since semantics aren't involved
2 other non-cognitive vision losses
-motion agnosia -cortical color blindness (cerebral chromatopsia)
cortical color blindness
-V8 damage -unilateral, bad if bilateral
Simultanagnosia (dorsal or ventral) failed tests
LMoM -learn -motor free -make -likely to fail all 6
What path
ventral from occipital cortex to inferotemporal cortex -single obj recognition and discrimination
face agnosia (Prosopagnosia) 1 thing
-no face recognition without voice
Hemispatial neglect 3 things
-no info opposite of lesion -remember all scenes but the contralateral side doesn't make sense -pt denies problem
form agnosia
-no visual form discrimination/orientation of simple forms (real object is better, touching object helps) -VA grating, color, depth still fun
ruff-light trail learning test (RULIT)
-short term memory + spatial perception abilities -frontal/pre-frontal and posterior parietal cortex -tests R hemisphere
judgement line orientation
-shows dec ability to perceive spatial orientation -tests R hemisphere -lines encoded by V1, more specialized area of LO and LOC -spatial relationship bt lines by posterior parietal cortex
semantic dementia deficit regions
-temporal lobes (L>R), frontal lobes (L>R) -associated with stroke, closed head injury, post-surgery, viral encephalitis, Alzheimer's
Blindsight 2 things
-unilateral hemianopia, or bilateral blindness -can ID in blindfield when pressured
topographic (place) agnosia deficit region
-ventral medial occipitotemporal cortex (fusiform or lingual gyro) -bilateral lesions produce this, lesion in R hem alone produces small deficit -common R or bilateral PCA infarct , or injury to small vessel ischemic disease
Blindsight CVF tests they fail
BMLM -make -learn -motor free -all 6 will probably have errors
apperceptive agnosia 2 things
FApS -form agnosia -simultagnosia
form agnosia failed tests
FFMMLeL -form -motor-free -make -learn -line
Hemispatial neglect deficit region
IPP inferior and posterior parietal (R>L) -other frontal areas involved (FEF, IFL, MFL, thalamus) -often damage due to PCA stroke
Hemispatial neglect CVL tests failed (most to least likely)
LiLM -line -learn -make -likely to fail all 6
Optic ataxia tests they fail 3 things
OALM -learn -make -rarely errors in motor free tests unless lesion extends posterior and inferior parietal cortex
Most dangerous artery
PCA -stroke involves PCA (MCA contributes much less)
Where path
dorsal from occipital cortex to posterior parietal cortex - Where's dori, pp, many objects motor help
what does topographic (place) agnosia coincide with?
face agnosia bc of proximity
Optic Aphasia deficit region
left posterior hemisphere -occipital cortex, white matter extending to posterior corpus callous -deficit in left hem bc this is dom for language and speech
attention categorization: object based neglect
neglect R or L half of objects
attention categorization: space based neglect
neglect VF to R or L of fixation
form agnosia is opposite of what?
optic ataxia (accurate perception but poor motor action)
associative agnosia 5
place, face, hemi, phase, dementia -hemispatial neglect -face agnosia -topographical (place) agnosia -optic aphasia -semantic dementia
Optic ataxia deficit region
posterior parietal cortex + superior colliculus (PRR, LIP, AIP)
motor-free visual perception test (MVPT-3)
tests 5 visual perception abilities 1. spatial relationship (object to self) 2. visual discrimination (discriminate dom features of object) 3. figure-ground relationship (object from background) 4. visual closure (discriminate whole figure when only fragments are present) 5. visual memory (recon after only brief time) -V1 and LO tested for recognition -posterior parietal cortex for spatial relationships -anterior parietal lobe, frontal lobe, medial temporal lobe
facial recognition
tests brain disease to inferotemporal cortex (FFA, pFus) -FFA of VOT and pFus of LOC encode info, LO of LOC can also
what is most susceptible to brain trauma
white matter to trauma