Optic ataxia Flashcards
1
Q
IMAGE ON LECTURE SLIDES
A
IMAGE ON LECTURE SLIDES
2
Q
What area is primary motor cortex
A
Broddmans area 4
3
Q
main functions of BA4 (?/3)
A
- receives projections from PMC and Somatosensory area 1
- projects to spinal chord
- most commands delivered from spinal chord to muscle
4
Q
Pre motor cortex areas
A
BA 6 &8
5
Q
BA 6 & 8 motive (?/2)
A
- projects to spinal chord and M1 (voluntary moment)
- recieves from PFC, PPC and M!
6
Q
PPC
A
posterior prefrontal crotex
7
Q
PFC
A
prefrontal cotex
8
Q
M1
A
controls voluntary movement
9
Q
BA6 split to 2
A
Dorsal area 6 and Ventral area 6
10
Q
Dorsal area 6
A
responsible for coding of reaching and arbitray responses to stimuli. Its subset is SMA
11
Q
SMA
A
Supplementary motor area - sequences movements
12
Q
Ventral area 6
A
responsible for coding of grasping and Brocas area (BA 44,45)
13
Q
Brocas area
A
responsible for Vocal musculature
14
Q
Area 8 (FEF)
A
Codes voluntary eye movement - frontal eye fields
15
Q
Other areas of the motor brain - list them
A
Cerebellum, Basal ganglia, Left IPL, PFC, PPC
16
Q
Cerebellum
A
timing, coordination and learning
17
Q
Basal ganglia
A
force profuction and kinematics.
18
Q
Left IPL
A
inferior parietal lobule - Praxis (Praxis refers to the process by which a skill is enacted or the performance of an action).
19
Q
PFC (motor purpose)
A
long-planning, decision making
20
Q
PPC (motor purpose)
A
eye movements, limb movements and attention
21
Q
Visual Brain areas
A
BA 17 (v1), BA 18(v2), BA19 (other secondary visual areas).
subcortical areas such as tegmentum, superior colliculus,etc.
22
Q
Visual areas commonality
A
Cortical visual areas project largely to the
temporal and parietal lobes
23
Q
Visual brain (2) - other areas
A
Middle and inferior temporal cortex area also visual.
24
Q
Visual brain purpose
A
Responsible for visual recognition processes Eg faces objects and patterns.
25
Visual brain projects to...
Parietal lobe.
26
Parietal lobes areas
split into anterior somatosensory zone (1-3, 43).
Posterior zone (5,7,39,40)
27
PL pathways
5 main pathways of the PL
28
Parietal lobe
BA 1-3 recieves special inputs from the spinal chord.
29
Anatomy of the parietal lobes (1)
BA 5 recieves input from BA1-3 and outputs to M1 and PMC
30
Anatomy of the parietal lobes (2)
Anterior BA7 recieves input from BA5, M1, PMC and area 39 - outputs to M1 and PMC.
31
Anatomy of parietal lobes 3
Posterior BA7 recieves visual, somaesthetic, proprioceptive, auditory, vestibular, oculomotor and cingulate inputs
32
somaesthetic
Another word for somatosensory
33
proprioceptive
the sense that provides information about the spatial position and movement of different body parts in relation to each other and the environment
34
vestibular
relates to vestibular system, balance from inner ear
35
oculomotor
relating to eye movemetns
36
Cingulate
an extensive area of the limbic system that plays a key role in pain processing, particularly in the affective-motivational aspects
37
Anatomy of parietal lobes (4)
Posterior PL is interconnected with prefrontal cortex, especially within area 46 - both PPL and PFC project to the same areas of the Temp. lobe.
38
Theory of parietal lobe functions
Anterior zone largely connected with somatosensation - intergrates it with visual information and lesser so, but still other senses.
39
Spatial processing
Both the anterior and posterior PL zones play a large role in spatial processing.
40
Why is spatial processing important in APL and PPL
1) object recognition
2) navigation
3) Visuomotor processing - where vision meets somatosensation shows visually guided movements
41
somatosensory symptoms of parietal lobe lesions *01
Primary Dmg to BA 1-3 and secondary BA 5 somatosensory cortex
42
*01 How this effects the body (dmg to BA 1-3 and 5)
problems with proprioception and tactile perception. This can also lead to afferent paresis in fingers
May cause astereognosis (touch recognition) and anasognosia.
43
Symptoms of PPC damage
Dmg in wernickes area; Wernickes aphasia. can cause problems in reading and writing
44
Symptoms of PPC damage (2)
left right dsicrimination.
45
left right discrimination.
Memory for ‘left’ vs.
‘right’ is disturbed
following lesions of left IPL
46
Dyscalculia
An inability to do calculations mentally
47
Dyscalculia causes
Incapability to do basic math -
48
right PL dmg
can cause spatial cognition
49
Unilateral neglect caused by ...
dmg to IPL and adjacent regions
50
Object recognition who
(warrington and taylor 1973)
51
Object recognition (warrington and taylor 1973) what
showed that patients with right
PL damage could recognise an
object viewed canonically, but
not when presented noncanonically
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Object recognition support
dmg in right pl causing object recogniton supports right pl is used in spatial manipulations of images
53
Balints syndrome
Balint 1909 had a case with bilateral PPC lesion - intact visual, object recognition and usage but faced
- neglect
- simultagnosia
- optic ataxia
54
simultagnosia
when his attention was directed
towards an object, he did not notice other objects
without prompting from the examiner
55
Optic ataxia
a severe deficit in reaching under visual guidance
56
optic ataxia associarions
Cannot be explained by elementary
visuoperceptual, attentional, proprioceptive, or
motor deficits.
Associated with lesions around and superior to
the intraparietal sulcus
57
problem with optic ataxia
Rarely studied (about 50 reported cases to date)
because symptoms are often subtle. not hemispherical
58
the fact that its not hemispherical means
it is an older evolutionary function
59
histoical cases
Crougneau (1884)
Balint (1909)
60
Crougneau (1884)
first to decribe misreaching behaviour after PPC dmg
61
Balint
patient innaccurate in reaching with one hand in one visual field.
The problem is not simple as it affecrts one side not both
62
Balint...
The problem is not simple as it affecrts one side not both... meaning
not a simple motor or visuoperceptual or attentional problem. Therefore it must be a visuomotor system
63
The Perenin and Vighetto studies
Largest reports of optic ataxia came from Perenin and Vighetto in 1983.
Found several patients with OA.
Testes on pointing to targets in periphal and posting their hand in a slot..
64
Historical studies (Perenin and Vighetto 1983)
Pointinf error are more common in VF contralateral to the lesion and to more strongly affect the contrahand.
65
Posting errors were of three main types
(Perenin and Vighetto 1983)
1) Misoriented hand to opening
2) missed hole or board entirely
3) sometimes misshaped hand
66
Follow up to Perenin and Vighetto (1988)
found patients much improved on both tasks though some errors still occurred
67
Deficits in optic ataxia (1)
- pointing to targets in the periphery
(fixate central location, point to a peripheral target)
68
Deficits in optic ataxia (2)
- posting hand in slot
(slot in variour orientations, also in visual periphery).
69
Deficits in optic ataxia (3)
- grasping (Jakobson et al 1991).
time course of grip aperture is affected
70
Deficits in optic ataxia (4) - track
manual tracking , target oves about at random must track target with finger
71
Mediating factors
- Fixation of the target
- practice or familiatity
- previews
- visual feedback
72
mediating factors (1) - Fixation of the target
almost all OA patients can point to target they fixate on
73
mediating factors (2) - practice or familiatity
improves performance, for example Jeannerod 1995, the patient AT lipstick study.
74
mediating factors (3) - previews
when the target is viewed prior to onset of the movement, OA patients improve
75
mediating factors (4) - visual feedback
does not improve OA performance (can in fact make it worse)
76
Theory of OA - Visuomotor
clearly a result of dmg to PPC, it is dissociable from visuoperceptual, motor, praxic, attentional disorders. Shows problems with visuomotor processing
77
Four explanations for OA
1) Visuomotor transformation Hypo.
2) Online control Hypo.
3) Attentional Deficit Hypo.
4) Perception Hypo.
78
Visuomotor transformation Hypo (1)
OA shows problem with tranforming visual input to motor outputs
79
Visuomotor transformation Hypo. (2)
Visual input arrives in retinocentric coordinates, motor output uses other body centred coordinates (eg hand centred)
80
Visuomotor transformation hypo (3)
OA patients represent the other half of a double dissociation with visual agnosia - such as patient DF, severely damaged perceptions but relatively intact, visuomotor performance
81
Visuomotor transformation Hypo. (4) - DF
DF can post her hand in a slot but cannot rotate a card to match the slots orientation.
DA patients have the DF impaired visuomotor guidance with relatively intact perceptions
82
