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Glossary of Lecture 11

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What damage did pt DF have?
V2, V3, and V4 to the ventral stream
What could DF do?
Could draw from memory - drawing w/ eyes closed helped
know meaning and form of objects, just couldn't recognize
How did apperceptive agnosics perform on the matching orientation aperture task?
At chance
How did apperceptive agnosics perform on the verbal report of right, left, vert, horz tilt?
Trouble w/ explict forms of shape ID, matching and identification
How did apperceptive agnosics perform on the hand posting task?
Can do this - brain processing direction of aperture and use shape info for guiding action
Apperceptive agnosics are
Impaired:
Spared:

impaired: explicit orientation tasks: verbal orientation and matching
spared: implicit orientation tasks, hand posting
Implications of the hand posting task:
orientation and shape reps available for guiding action
apperceptive agnosics have spared process ___ to act in space through __ knowledge of direction orientation is ___
How, explict, gone
Parietal Lobe Functions: (2)
1. Visual guided behaviors
2. directing attention: overt and covert shifts
Apperceptive agnosics have shape info __ and can __ objects
intact, grasp
Balint's syndrome:
disorder of space exploration and spatial cognition
Baliants syndrome occurs b/c of __ __ __ damage which makes it rare
bilateral posterior parietal
5 elements of Baliant's syndrome:
1. optic ataxia
2. gaze apraxia
3. spatial disorientation
4. simultanagnosia
5. sparing of shape, face, color and word recognition



optic ataxia:
disorder of reaching and other visually guided movements of the limbs
ataxia:
loss of coordinated movements that are not nec learned but are a sequence of properly coordinated movement
Baliant's syndrome pt's cannot do hand posting due to __ __ b/c they cannot accurately guide hand thru aperture
optic ataxia
What is the double dissociation between DF and Baliant's pts?
DF: cannot do explict ID but can do hand posting (ventral probs)
Baliant's: cannot do hand posting but can do explicit ID (dorsal probs)
Gaze apraxia:
inability to move eyes voluntarity in the VF
apraxia:
disorder of skilled and voluntary movements
with gaze apraxia, spontaneous, reflexive movements are spared so eyes are not __ but it is the __ to move gaze __ meaning the head jerks toward object to facilitate eye movement
paralyzed, inability, voluntarily
What do scanpaths look like for ppl with Bilant's?
It will be jerky or random whereas normal ppl will look at dense portions (eyes, mouth, nose)
also cannot trace shapes but can ID them
simultanagnosia:
inability to see more than one object at a time - pts will only see one object
with simultanagnosia: in order to be recognized there may need to be a __ __ otherwise they cannot see more than one item
space code
__ principles are mediated by the __ stream which is still intact for pts with simultanagnosia
grouping, ventral
Baliant's pts can still do complex shape recognition b/c the __ stream is spared and words can be recognized because letters are ___
ventral, grouped
constructional apraxia:
impaired building, assembling and drawing - DOLs
constructional apraxia test:
block design - trouble orienting blocks in right way inability to appreciate the spatial relations of the objects they are looking at
and impaired Rey-Osterreith Complex Figure tasks
7 Right Parietal Symptoms (unilateral)
1. left hemiparetic arm: weakness in left arm
2. anosognosia: unawareness/denial of illness
3. constructional apraxia: difficulty with construction of skilled things
4. visual and tactile extinction
5. allesthesia
6. rightward gaze
7. left neglect





allesthesia:
mislocation of stimulation: if stimuli coming from L will attribute from R
Extinction:
Presence of stimulus in R field leads to the simulus in the L filed being extinguished from awarness
Right parietal damage so __ object extinguished
contralateral
8 neglect behaviors:
1. react to speech and sounds coming from contralateral side
2. failure to recognize neglect arm as own
3. act as if one side of space doesn't exist
4. fail to draw side of object in neglected hemi-space
5. reading 1/2 lines of text
6. leave food 1 side plate
7. shave 1 side face
8. dress 1 side body






Unilateral neglect is a deficit in __ and __ to stimulation on the side ___ to damage
percieving and responding, contralateral
Neglect is not:
1. __ or __
2. not prob w/ __ __

blindness and paralyzed
not prob w/ primary sensory
Heminopia:
VF blindness - are aware of this so not neglect
Where is the typical lesion site for neglect?
Right posterior parietal lesion
Reference Frame:
system for representing locations relative to some real or arbitrary standard
neglect can impact __ reference frames
multiple
Egocentric space:
locations defined relative to the observer
3 egocentric reference frames:
1. retina
2. head
3. body midline

allocentric space:
locations defined independent of the observer in relation to gravity or other objects
Hemispatial Reference frame:
defined relative to body midline: right midline - right hemi
somatopic reference frame:
relation to parts of body - R and L hands
Retinotopic reference frame:
relation to retina
3 Theories of Neglect:
1. Bisiach's Represational Account
2. Posner's Precueing Task
3. Kinsbourne's Orienting Model

What is Bisach's Representational Account to explain neglect?
neglect is due to problem with forming mental representation by the damage hemisphere no matter if it is physical or imagined
Bisach's Representational Account for right parietal damage:
lack the left side of space no matter where standing - ignore this side of space
What is Posner's Precueing Task?
Focus on a central point: one of the two boxes brightens and find astrik
Valid: box that brightens has astreik - cues attn
Invalid: box brightens doesn't have astrik

Posner's spotlight hypothesis:
attention moves around like a spotlight - eyes in one spot but have covert attention (area around it like a spotlight)
Neglect Performance on Posner Task:
overall slower performance on the invalid cues - very slow to respond to target in left
Why does Kinsbourne think that L neglect is more common than R neglect in right handers?
Normally L hemi has a rightward orienting bias that is counterbalanced by the R hemi, but b/c R-handed indiv have L hemi dom what see in neglect is failure to attend to L and hyper attn to the R

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