major theoretical accounts What could go wrong after RH damage explaining the contralesional neglect Attentional disorders Spatial representation disorders Premotor representation disorders 2 ID: 217212
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Slide1
Unilateral neglect
major theoretical accountsSlide2
What could go wrong after RH damage explaining the contralesional neglect?
Attentional disorders
Spatial representation disordersPre-motor representation disorders
2Slide3
Attention theories:
Heilman
Reduced arousal of right hemisphereAsymmetry of attention controlAttention to the left side of space is provided exclusively by the right hemisphere whereas
Attention to the right side of space is provided by both hemispheres.
3Slide4
Asymmetric Attention Control
4Slide5
Attention Control in Neglect
5Slide6
Attention theories:
Kinsborne
Hemispheric rivalry predicts:Gradients rather then hemifield effects‘Hyperattention’ on the right (‘magnetism’)Extinction in the
ipsi-lesional
side
6Slide7
Unilateral Neglect
7Slide8
“Starry Night” test
8Slide9
S
110
S
6
-3
-2
-1
|
1
2
3
S
3
0
0.5
1
1.5
2
2.5
RT/midline-RT
-3
-2
-1
|
1
2
3
S
8
0
0.5
1
1.5
2
2.5
RT/midline-RT
Reaction Time - neglect patients
Deouell et al., 2000
9Slide10
Anderson (1996) Salience model
10Slide11
Attention theories: Posner
Covert shifts of attention
Parietal - DisengageSup. Colliculus
- Move
Thalamus - Engage
11Slide12
Pulvinar
Superior Colliculus
Move
Engage
TPJ
Disengage
Controlling spatial attention beam: Posner
12Slide13
Posner’s cueing paradigm
*
*
13Slide14
Posner’s paradigm
- valid cue
*
Fixation
Valid cue
Target
14Slide15
Posner’s paradigm -
invalid cue
*
Fixation
Invalid cue
Target
15Slide16
07.42
7.42
Fig. 2, Posner et al., “Effects of parietal injury on covert orienting of attention,” The Journal of Neuroscience 4: 1863–1874, (1984). Adapted with permission of The Society for Neuroscience.
16Slide17
07.09
Posner, M.I., Snyder, C.R.R., and Davidson, J., Attention and the detection of signals, Journal of Experimental Psychology: General 109 (1980): 160–174. Copyright © 1980 by the American Psychological Association. Adapted with permission.
Cost
Benefit
17Slide18
Attentional systems (Posner)
Posterior Attentional System (Orienting)
18
Anterior Att. System (Target Detection)
Vigilance/Alerting SystemSlide19
New formulation (Corbetta)
Stimulus + Response Selection
Alerting, Sensory Reorienting
Cingulate – Response monitoring, not selection …
19Slide20
Functions of parietal lobes
Dror
– Breakdown of connectivityAdi – IPL and attention theories of neglectRonen
– The role of the parietal lobes in timing events.
20Slide21
Representational Theories
Bisiach - Neglect is a disorder of space representation
Neglect is demonstrated in imagery (Piazza effect)If attention is shifted, it is shifted over an internal representation of space (rather than space itself)
Damage to circuits representing segments of space precludes action towards these segments
21Slide22
Representational Theories
Piazza del Duomo effect
22Slide23
Piazza del
Duomo
effectSlide24
24Slide25
25
הזנחת צד - ייצוג מנטליSlide26
Is the number larger than…
Increase in RT just to the left of the target number
Vuilleumier et al., 2004
26Slide27
Gradient of Neglect and Parietal Neurons
Pouget
and Driver 2000
27Slide28
Reaction Time
Accuracy
RHS
LHS
Control
600
1000
500
600
400
450
80%
100%
80%
100%
80%
100%
-3
-2
-1
|
1
2
3
84
88
92
96
100
-3
-2
-1
|
1
2
3
400
600
800
1000
RHS
LHS
Control
RHS
LHS
Control
LEFT
Right
Bottom
Top
RT (msec)
Hits (percent)
Deouell et al., 2005
28Slide29
Subtypes of neglect?
Buxbaum et al., 2004
29Slide30
Role of non-spatial effects
Robertson et al., 1998, Nature
TOJ task:
30Slide31
Robertson et al., 1998
31