Optic ataxia Flashcards

1
Q

IMAGE ON LECTURE SLIDES

A

IMAGE ON LECTURE SLIDES

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2
Q

What area is primary motor cortex

A

Broddmans area 4

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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
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4
Q

Pre motor cortex areas

A

BA 6 &8

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5
Q

BA 6 & 8 motive (?/2)

A
  • projects to spinal chord and M1 (voluntary moment)
  • recieves from PFC, PPC and M!
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6
Q

PPC

A

posterior prefrontal crotex

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7
Q

PFC

A

prefrontal cotex

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8
Q

M1

A

controls voluntary movement

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9
Q

BA6 split to 2

A

Dorsal area 6 and Ventral area 6

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10
Q

Dorsal area 6

A

responsible for coding of reaching and arbitray responses to stimuli. Its subset is SMA

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11
Q

SMA

A

Supplementary motor area - sequences movements

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12
Q

Ventral area 6

A

responsible for coding of grasping and Brocas area (BA 44,45)

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13
Q

Brocas area

A

responsible for Vocal musculature

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14
Q

Area 8 (FEF)

A

Codes voluntary eye movement - frontal eye fields

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15
Q

Other areas of the motor brain - list them

A

Cerebellum, Basal ganglia, Left IPL, PFC, PPC

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16
Q

Cerebellum

A

timing, coordination and learning

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17
Q

Basal ganglia

A

force profuction and kinematics.

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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).

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19
Q

PFC (motor purpose)

A

long-planning, decision making

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20
Q

PPC (motor purpose)

A

eye movements, limb movements and attention

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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.

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22
Q

Visual areas commonality

A

Cortical visual areas project largely to the
temporal and parietal lobes

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23
Q

Visual brain (2) - other areas

A

Middle and inferior temporal cortex area also visual.

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24
Q

Visual brain purpose

A

Responsible for visual recognition processes Eg faces objects and patterns.

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25
Q

Visual brain projects to…

A

Parietal lobe.

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26
Q

Parietal lobes areas

A

split into anterior somatosensory zone (1-3, 43).
Posterior zone (5,7,39,40)

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27
Q

PL pathways

A

5 main pathways of the PL

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28
Q

Parietal lobe

A

BA 1-3 recieves special inputs from the spinal chord.

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29
Q

Anatomy of the parietal lobes (1)

A

BA 5 recieves input from BA1-3 and outputs to M1 and PMC

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30
Q

Anatomy of the parietal lobes (2)

A

Anterior BA7 recieves input from BA5, M1, PMC and area 39 - outputs to M1 and PMC.

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31
Q

Anatomy of parietal lobes 3

A

Posterior BA7 recieves visual, somaesthetic, proprioceptive, auditory, vestibular, oculomotor and cingulate inputs

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32
Q

somaesthetic

A

Another word for somatosensory

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33
Q

proprioceptive

A

the sense that provides information about the spatial position and movement of different body parts in relation to each other and the environment

34
Q

vestibular

A

relates to vestibular system, balance from inner ear

35
Q

oculomotor

A

relating to eye movemetns

36
Q

Cingulate

A

an extensive area of the limbic system that plays a key role in pain processing, particularly in the affective-motivational aspects

37
Q

Anatomy of parietal lobes (4)

A

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
Q

Theory of parietal lobe functions

A

Anterior zone largely connected with somatosensation - intergrates it with visual information and lesser so, but still other senses.

39
Q

Spatial processing

A

Both the anterior and posterior PL zones play a large role in spatial processing.

40
Q

Why is spatial processing important in APL and PPL

A

1) object recognition
2) navigation
3) Visuomotor processing - where vision meets somatosensation shows visually guided movements

41
Q

somatosensory symptoms of parietal lobe lesions *01

A

Primary Dmg to BA 1-3 and secondary BA 5 somatosensory cortex

42
Q

*01 How this effects the body (dmg to BA 1-3 and 5)

A

problems with proprioception and tactile perception. This can also lead to afferent paresis in fingers
May cause astereognosis (touch recognition) and anasognosia.

43
Q

Symptoms of PPC damage

A

Dmg in wernickes area; Wernickes aphasia. can cause problems in reading and writing

44
Q

Symptoms of PPC damage (2)

A

left right dsicrimination.

45
Q

left right discrimination.

A

Memory for ‘left’ vs.
‘right’ is disturbed
following lesions of left IPL

46
Q

Dyscalculia

A

An inability to do calculations mentally

47
Q

Dyscalculia causes

A

Incapability to do basic math -

48
Q

right PL dmg

A

can cause spatial cognition

49
Q

Unilateral neglect caused by …

A

dmg to IPL and adjacent regions

50
Q

Object recognition who

A

(warrington and taylor 1973)

51
Q

Object recognition (warrington and taylor 1973) what

A

showed that patients with right
PL damage could recognise an
object viewed canonically, but
not when presented noncanonically

52
Q

Object recognition support

A

dmg in right pl causing object recogniton supports right pl is used in spatial manipulations of images

53
Q

Balints syndrome

A

Balint 1909 had a case with bilateral PPC lesion - intact visual, object recognition and usage but faced
- neglect
- simultagnosia
- optic ataxia

54
Q

simultagnosia

A

when his attention was directed
towards an object, he did not notice other objects
without prompting from the examiner

55
Q

Optic ataxia

A

a severe deficit in reaching under visual guidance

56
Q

optic ataxia associarions

A

Cannot be explained by elementary
visuoperceptual, attentional, proprioceptive, or
motor deficits.
Associated with lesions around and superior to
the intraparietal sulcus

57
Q

problem with optic ataxia

A

Rarely studied (about 50 reported cases to date)
because symptoms are often subtle. not hemispherical

58
Q

the fact that its not hemispherical means

A

it is an older evolutionary function

59
Q

histoical cases

A

Crougneau (1884)
Balint (1909)

60
Q

Crougneau (1884)

A

first to decribe misreaching behaviour after PPC dmg

61
Q

Balint

A

patient innaccurate in reaching with one hand in one visual field.
The problem is not simple as it affecrts one side not both

62
Q

Balint…
The problem is not simple as it affecrts one side not both… meaning

A

not a simple motor or visuoperceptual or attentional problem. Therefore it must be a visuomotor system

63
Q

The Perenin and Vighetto studies

A

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
Q

Historical studies (Perenin and Vighetto 1983)

A

Pointinf error are more common in VF contralateral to the lesion and to more strongly affect the contrahand.

65
Q

Posting errors were of three main types
(Perenin and Vighetto 1983)

A

1) Misoriented hand to opening
2) missed hole or board entirely
3) sometimes misshaped hand

66
Q

Follow up to Perenin and Vighetto (1988)

A

found patients much improved on both tasks though some errors still occurred

67
Q

Deficits in optic ataxia (1)

A
  • pointing to targets in the periphery
    (fixate central location, point to a peripheral target)
68
Q

Deficits in optic ataxia (2)

A
  • posting hand in slot
    (slot in variour orientations, also in visual periphery).
69
Q

Deficits in optic ataxia (3)

A
  • grasping (Jakobson et al 1991).
    time course of grip aperture is affected
70
Q

Deficits in optic ataxia (4) - track

A

manual tracking , target oves about at random must track target with finger

71
Q

Mediating factors

A
  • Fixation of the target
  • practice or familiatity
  • previews
  • visual feedback
72
Q

mediating factors (1) - Fixation of the target

A

almost all OA patients can point to target they fixate on

73
Q

mediating factors (2) - practice or familiatity

A

improves performance, for example Jeannerod 1995, the patient AT lipstick study.

74
Q

mediating factors (3) - previews

A

when the target is viewed prior to onset of the movement, OA patients improve

75
Q

mediating factors (4) - visual feedback

A

does not improve OA performance (can in fact make it worse)

76
Q

Theory of OA - Visuomotor

A

clearly a result of dmg to PPC, it is dissociable from visuoperceptual, motor, praxic, attentional disorders. Shows problems with visuomotor processing

77
Q

Four explanations for OA

A

1) Visuomotor transformation Hypo.
2) Online control Hypo.
3) Attentional Deficit Hypo.
4) Perception Hypo.

78
Q

Visuomotor transformation Hypo (1)

A

OA shows problem with tranforming visual input to motor outputs

79
Q

Visuomotor transformation Hypo. (2)

A

Visual input arrives in retinocentric coordinates, motor output uses other body centred coordinates (eg hand centred)

80
Q

Visuomotor transformation hypo (3)

A

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
Q

Visuomotor transformation Hypo. (4) - DF

A

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
Q
A