Control of Voluntary Attention in Human Cortex

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Control of Voluntary Attention in Human Cortex

• Steven Yantis
• Department of Psychological and Brain Sciences
• The Johns Hopkins University
• Baltimore, USA

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Selective Attention

• Perception is selective we perceive only a small
  subset of the information available in a scene
• Selective attention is active and goal-driven
• Investigations of selective attention have
  addressed
• How sensory input is modulated
• How attentional modulation is controlled

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From Yesterday . . .

• Domains of selection
• Locations
• Features
• Objects
• Sensory modalities (vision, audition, touch)
• Modes of attentional control
• Voluntary, top-down, goal-directed
• Involuntary, bottom-up, stimulus-driven

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From Yesterday . . .

• Domains of selection
• Locations
• Features
• Objects
• Sensory modalities (vision, audition, touch)
• Modes of attentional control
• Voluntary, top-down, goal-directed
• Effects of attention in sensory cortex
• Control of attention in frontoparietal cortex

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Some targets of attentional modulation
hMT (motion)
V1-V4 (early vision)
Superior temporal gyrus (early audition)
Fusiform gyrus (faces/houses)
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Sensory Effects
Control
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Motter (1994). J. Neuroscience, 14, 2190-2199.
V4 receptive field
Instructional fixation pt
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V4
Switch attention into RF
Switch attention out of RF
Motter (1994). J. Neuroscience, 14, 2190-2199.
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F.M. Kirby Research Center for Functional Brain
ImagingKennedy Krieger Institute _at_ Johns Hopkins
University
mri.kennedykrieger.org
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Blood Oxygenation Level Dependent (BOLD) fMRI

• Increase in neural activity causes local change
  in blood oxygenation
• Change in the relative amount of oxygenated and
  deoxygenated hemoglobin causes a change in the
  fMRI signal
• An increase in BOLD reflects an increase in
  neural activity
• Compare BOLD signal in two tasks that differ in a
  cognitive function of interest to measure neural
  activity associated with that cognitive function

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BOLD response in a single voxel in primary visual
cortex following 1-sec visual stimulation
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Domains of selection Locations
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Domains of selection Locations
Tootell, et al. (1998). Neuron, 21, 1409-1422.
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Domains of selection Locations
Tootell, et al. (1998). Neuron, 21, 1409-1422.
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Domains of selection Locations
Tootell, et al. (1998). Neuron, 21, 1409-1422.
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Retinotopy of visual attention
DeYoe Brefzinski (Nature Neurosci, 1999)
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Retinotopy of visual attention
DeYoe Brefzinski (Nature Neurosci, 1999)
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Attending to multiple locations
McMains Somers (Neuron, 2004)
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Attending to multiple locations
McMains Somers (Neuron, 2004)
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Attending to multiple locations
McMains Somers (Neuron, 2004)
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Kastner et al. (1999). Neuron 22, 751-761.
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Kastner et al. (1999). Neuron 22, 751-761.
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Domains of selection Features
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OCraven et al. (1997). Neuron 18, 591598.
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Domains of selection Features
OCraven et al. (1997). Neuron 18, 591598.
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Domains of selection Objects
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Object-based attention
OCraven, Downing, and Kanwisher (Nature, 1999)
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OCraven, Downing, and Kanwisher ( Nature, 1999)
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Cross-modal attention shift task
auditory
STIMULI Three auditory letter streams
(1) Attended
(23) Ignored
Cue 16s
T
A
K
F
250 ms
X
Five visual letter streams (1)
Attended central stream (2-5) Ignored
peripheral streams
V
Y
G
N
H
U
Digit Targets 4 SHIFT to unattended
modality 2 HOLD on attended modality
T
R
V
A
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Visual cortex timecourse
Switch audition to vision
Attend to vision
Switch vision to audition
Attend to audition
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Summary Sensory Effects in Multiple Domains of
Selective Attention

• Attention can modulate cortical activity by
  selecting
• Locations
• Features
• Objects
• Sensory modalities
• Sources of attentional control

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V4
Reynolds Chelazzi, Desimone (1999). J.
Neuroscience, 19, 1736-1753.
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Attention as Biased Competition
competition
Framework Desimone Duncan (1994). Ann Rev
Neurosci Neurophysiological evidenceReynolds et
al. (1999). J Neurosci
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Attention as Biased Competition
SPL
PFC
Top-Down Biasing Signal Attentional Control
competition
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Some sources of attentional control
Superior parietal lobule (SPL) and precuneus
Frontal eye fields (FEF)
Intraparietal sulcus (IPS)
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Unilateral visual neglect following damage to
posterior parietal lobe
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Unilateral visual neglect following damage to
posterior parietal lobe
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Corbetta et al. (J. Neuroscience, 1993)
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Corbetta et al. (J. Neuroscience, 1993)
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Kastner Ungerleider (Ann. Rev. Neurosci., 2000)
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Bisley, J.W. and Goldberg, M.E. (2003) Science,
299, 81-86.
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Bisley, J.W. and Goldberg, M.E. (2003) Science,
299, 81-86.
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Behavioral sensitivity
Response in LIP (parietal cortex)
Response to distractor
Response to target
Bisley, J.W. and Goldberg, M.E. (2003) Science,
299, 81-86.
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Moore, T., Armstrong, K. M. (2003). Nature 421,
370 - 373
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Moore, T., Armstrong, K. M. (2003). Nature 421,
370 - 373
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Control of Spatial Attention Shifts

• Monitor top-down attentional modulation of early
  sensory representations in extrastriate cortex
• Examine the time course of attention-switch
  activity reflecting the neural basis of
  attentional control

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Rapid Serial Visual Presentation (RSVP) task
Background Reeves Sperling (1986). Psychol
Rev, 93, 180-206.
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Features of the RSVPAttention-Switching Task

• 1. Many distracting stimuli near targets provide
  competition

• ?Magnifies attentional modulation

2. The attention switch signal (cue) is not a
separate sensory event but embedded within a
steady-state visual stream
?Allows estimation of neural events following
switch signal that are not sensory
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Blood Oxygenation Level Dependent (BOLD) fMRI

• Increase in neural activity causes local change
  in blood oxygenation
• Change in the relative amount of oxygenated and
  deoxygenated hemoglobin causes a change in the
  fMRI signal
• An increase in BOLD reflects an increase in
  neural activity
• Compare BOLD signal in two tasks that differ in a
  cognitive function of interest to measure neural
  activity associated with that cognitive function

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Early Visual Pathway
Each visual field is initially represented in the
contralateral visual cortex
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Event-Related Averaging
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Attend Left Contrasted with Attend
Right Extrastriate cortex
Yantis et al. (2002). Nature Neurosci.
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Shift Attention Contrasted with Hold
Attention Superior Parietal Lobule
Separately plot SHIFT followed by SHIFT vs.
SHIFT followed by HOLD HOLD
This signal does not maintain attentive state
instead, it transiently signals a shift of
attention
Yantis et al. (2002). Nature Neurosci.
Z55
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fixate
Spatial attention shifts among three locations
time
target
target
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Event Types
Shift from Center to Periphery
Shift from Center to Left
Shift from Center to Right
6
2
1
9
L
R
4
3
5
8
Fixation point
0
2
9
7
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Event Types
Shift from Periphery to Center
Shift from Left to Center
Shift from Right to Center
6
2
1
9
4
3
5
8
C
C
0
2
9
7
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Event Types
Shift Between Peripheral Locations
6
2
1
9
4
3
Shift from Left to Right
Shift from Right to Left
5
8
R
L
8
2
9
7
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Event Types
Hold Events
Hold Center
6
2
1
9
C
4
3
5
8
L
R
Hold Left
Hold Right
8
2
9
7
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Attentional Modulation of Extrastriate
Hold Left vs. Hold Right
Shift Left to Right Shift Right to Left
y -88
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Control of Attention
Z 45
Shift from Center to Periphery gt Shift from
Periphery to Center
Y -9
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Transient Shift-related Activity
Shift Left to Right Shift Right to Left
Z 45
Hold Left Hold Right
Y -9
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Transient Shift-related Activity
Shift Left to Right Shift Right to Left
Z 45
Hold Left Hold Right
Y -9
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Transient ActivityDecoupling Attention and
Fixation
IPS
Z 45
Shift Center to Left Shift Center to Right
Shift Left to Center Shift Right to Center
FEF
Y -9
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Sustained Activation for the Separation of
Attention and Fixation
IPS
Z 45
Hold Center
Hold Left Hold Right
FEF
Y -9
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Right FEF
Left FEF




Left PPC
Right PPC




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Sensory Effects
Control
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Experiment 2 Shifts of attention between visual
features

• Monitor feature-based attentional modulation of
  early sensory representations in ventral
  extrastriate cortex
• Investigate the neural basis of feature-based
  attentional control

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Feature-based attention shift task
Target Features
Shift color-to-motion Red Shift motion-to-color
Hold color Green Hold motion
demo
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Contrast attend to motion vs. attend to color
MT
Liu et al. (2003). Cerebral Cortex.
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Contrast shift vs. hold
Precuneus
Z45
Liu et al. (2003). Cerebral Cortex.
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Sensory Effects
Control
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Object-based attention
OCraven, Downing, and Kanwisher (Nature, 1999)
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Object-based RSVP task
READY
SHIFT
Get Ready Signal 6 sec
HOLD
2-4 Non-Targets
Face Hold Target Stay on Faces
TIME 1 Morph/sec
Face Shift Target Shift to Houses
House Hold Target Stay on Houses
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facesgthouses ROI
LatFus
R
Z -19
houses gt faces ROI
MedFus
Z -12
Serences et al. (2004). Cerebral Cortex.
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SPL
R
Z 46
Y -14
SFS/PreCeS
Serences et al. (2004). Cerebral Cortex.
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Shifts of attention between sensory modalities
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Cross-modal attention shift task
auditory
Cue 16s
T
A
K
F
250 ms
X
V
Y
G
N
H
U
T
R
V
A
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Contrast attention to auditory stream vs.
attention to visual stream
Superior temporal (auditory)
Ventral extrastriate (visual)
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Contrast shift vs. hold attention
precuneus
Right
Z48
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Nonspatial auditory shifts of attention
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Comparison of shift-related activation loci

• CAVEATS
• The stimuli in these experiments were different,
  and it is known that SPL is not equally
  responsive to all stimulus classes
• No direct contrast between domains of control has
  been carried out
• Therefore the following data are only suggestive
  and not definitive about whether the very same
  cortical regions are involved in these different
  domains

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Voluntary shifts of attention are accompanied by
transient activity in superior parietal and
frontal cortex in multiple attentional domains
R
Features Liu et al. (2003)
Space Yantis et al. (2002)
Z55
Z45
cross-modal (vision/audition) Shomstein Yantis
(2004)
Objects Serences et al (in press).
Z48
Z55
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Summary

• Shifts of attention between locations, features,
  superimposed objects, and sensory modalities
  modulate stimulus-specific activity in sensory
  cortex
• Activity in the superior parietal lobule and in
  FEF is associated with voluntary shifts of visual
  attention in all four domains, as well as shifts
  of attention between locations and objects in
  audition
• Sustained activity in these attentional control
  areas maintains a given attentive state
• A transient control signal issued by SPL is
  time-locked to voluntary shifts of attention