visual attention attention is the ability to select objects of interest from the surrounding...
TRANSCRIPT
![Page 1: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/1.jpg)
Visual AttentionVisual Attention
• Attention is the ability to select objects of interest from the
surrounding environment
• A reliable measure of attention is eye movement during
object (target) selection
• Early studies show that there are specific brain regions that
are involved in the process of target selection
![Page 2: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/2.jpg)
Visual AttentionVisual Attention
• Attention is the ability to select objects of interest from the
surrounding environment
• A reliable measure of attention is eye movement during
object (target) selection
• Early studies show that there are specific brain regions that
are involved in the process of target selection
– Superior Colliculus
![Page 3: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/3.jpg)
Visual AttentionVisual Attention
• Attention is the ability to select objects of interest from the
surrounding environment
• A reliable measure of attention is eye movement during
object (target) selection
• Early studies show that there are specific brain regions that
are involved in the process of target selection
– Superior Colliculus
– Frontal Eye Field
![Page 4: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/4.jpg)
Visual AttentionVisual Attention
• Attention is the ability to select objects of interest from the
surrounding environment
• A reliable measure of attention is eye movement during
object (target) selection
• Early studies show that there are specific brain regions that
are involved in the process of target selection
– Superior Colliculus
– Frontal Eye Field
– Extrastriate Areas (V1, V4, IT)
![Page 5: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/5.jpg)
Superior Colliculus & Target Superior Colliculus & Target Selection: Early StudiesSelection: Early Studies
• Cells in the superficial layers of the SC respond to light
falling on a specific area of the retina
• Visual response occurs 50ms after stimulus onset even
when the stimulus appears in the RF and the monkey
maintains fixation
![Page 6: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/6.jpg)
Superior Colliculus & Target Superior Colliculus & Target Selection: Early StudiesSelection: Early Studies
• Enhanced visual response when the stimulus appears in the
cell’s receptive field AND the monkey selects it as a target
and saccades (overtly attends) to it. Latency of saccade is
about 200ms
• Activity is greater for target + saccade than for target
![Page 7: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/7.jpg)
Superior Colliculus & Target Superior Colliculus & Target Selection: Early StudiesSelection: Early Studies
• No enhanced response when the monkey saccades to a
stimulus outside the receptive field (or in total darkness)
![Page 8: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/8.jpg)
Superior Colliculus & Target Superior Colliculus & Target Selection: Early StudiesSelection: Early Studies
• No enhanced response when the monkey covertly attends
to the stimulus in the receptive field
• At least this is what they found back then
![Page 9: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/9.jpg)
Conclusions from Early StudiesConclusions from Early Studies
• Early studies suggest that the superior colliculus is involved
in the selection of targets for eye movements
– Not just a visual response to stimulus
– Not just a motor response to saccade
• Greatest level of activity is found when both a target is
presented and a subsequent saccade is made to that target
![Page 10: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/10.jpg)
Target Selection and UncertaintyTarget Selection and Uncertainty
• Behavioral Task – Uncertainty period: array of
possible targets presented
– Selection period: one of the
targets is dimmed
– Removal of fixation signaled
saccade initiation
• Manipulated uncertainty by
varying the # of possible
targets (distractors)
• Recorded activity in SC
intermediate layer neurons
![Page 11: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/11.jpg)
Visual Response Modulated by Visual Response Modulated by Uncertainty / # of DistractorsUncertainty / # of Distractors
• Response during stimulus
onset in the uncertainty
period decreases as the #
of distractors (uncertainty
level) increases
• Response during selection
and saccade initiation were
not significantly different
regardless of uncertainty
![Page 12: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/12.jpg)
The Frontal Eye Field & Target The Frontal Eye Field & Target SelectionSelection
• FEF cells respond to visual stimuli like the SC
– Greater activity for spots of light in the receptive field
– RF is larger: as big as a ¼ of an entire visual field
![Page 13: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/13.jpg)
Decreased Activity with Increased Decreased Activity with Increased Uncertainty / # of DistractorsUncertainty / # of Distractors
![Page 14: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/14.jpg)
Superficial LayersSuperficial Layers
Intermediate andIntermediate andDeep LayersDeep Layers
Extrastriate CortexExtrastriate Cortex(e.g. V4, MT)(e.g. V4, MT)
Parietal Cortex (LIP)Parietal Cortex (LIP)
Frontal Eye FieldFrontal Eye Field
Medio-Dorsal ThalamusMedio-Dorsal Thalamus
Striate Cortex (V1)Striate Cortex (V1)
RetinaRetina
Brainstem SaccadeBrainstem SaccadeGeneratorGenerator
SCSC
Major Connections of the Superior Major Connections of the Superior ColliculusColliculus
![Page 15: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/15.jpg)
Superficial LayersSuperficial Layers
Intermediate andIntermediate andDeep LayersDeep Layers
Extrastriate CortexExtrastriate Cortex(e.g. V4, MT)(e.g. V4, MT)
Parietal Cortex (LIP)Parietal Cortex (LIP)
Frontal Eye FieldFrontal Eye Field
Medio-Dorsal ThalamusMedio-Dorsal Thalamus
Striate Cortex (V1)Striate Cortex (V1)
RetinaRetina
Brainstem SaccadeBrainstem SaccadeGeneratorGenerator
SCSC
Major Connections of the Superior Major Connections of the Superior ColliculusColliculus
![Page 16: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/16.jpg)
Early Studies of Target Selection Early Studies of Target Selection Activity in FEFActivity in FEF
• Detection Task– Target presented alone– Goal: saccade to target
• Visual Search Task– Target with distractors– Goal: saccade to target
• Recorded neural activity in FEF at two time intervals:– 100ms after stimulus onset– 100ms before saccade
![Page 17: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/17.jpg)
Selection-Dependent Visual ActivitySelection-Dependent Visual Activity
• Enhanced response when
the target is in the RF
• Greater response for target
alone (detection) than with
distractors (search)
• Suppressed activity when
the target is near the RF
only in search trials
![Page 18: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/18.jpg)
Target Selection in FEF NeuronTarget Selection in FEF Neuron
• Detection Trials– Activity decreased as distance
from RF increased
• Search Trials– Initial activity is the same,
since a stimulus (distractor) is
always present
– Enhanced activity for target in
RF
– Suppressed activity for target
near RF
![Page 19: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/19.jpg)
Go / No-go TaskGo / No-go Task
• Monkeys fixated on white spot
• Trigger signal: change of color
– Go trial (solid square): shift gaze to the target – saccade
– Nogo trial (asterisk): maintain fixation – no saccade
• Color change can occur before, during or after target onset
![Page 20: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/20.jpg)
Neural Response for Go & No-go TrialsNeural Response for Go & No-go Trials
![Page 21: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/21.jpg)
Evidence for Center-Surround ActivityEvidence for Center-Surround Activity
![Page 22: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/22.jpg)
FEF Connects to Extrastriate CortexFEF Connects to Extrastriate Cortex
![Page 23: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/23.jpg)
Target Selection in V4Target Selection in V4
![Page 24: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/24.jpg)
Visual Properties of IT NeuronsVisual Properties of IT Neurons
• Neurons respond selectively to complex objects
– Input: V1 and V4 (feature detection)
– Output: entorhinal cortex hippocampus (memory)
• Large receptive fields that always include the fovea
• Retinotopic organization is absent
• Invariant Properties
– Scale invariance: insensitive to changes in stimulus size
– Translation invariance: insensitive to changes in position
• Columnar organization
• IT neurons are expected to be involved in more complex
aspects of target selection
![Page 25: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/25.jpg)
Experimental DesignExperimental Design
• Good (square) and poor
(triangle) stimuli were
selected prior to task
• Sequence of Events
– cue delay target
– Saccade to target that
matches the cue
• Block trial: used one cue
for 20 – 30 trials
• Recorded activity in IT
![Page 26: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/26.jpg)
IT Neurons Carry Target InformationIT Neurons Carry Target Information
![Page 27: Visual Attention Attention is the ability to select objects of interest from the surrounding environment A reliable measure of attention is eye movement](https://reader036.vdocuments.mx/reader036/viewer/2022062518/56649cb55503460f9497a27c/html5/thumbnails/27.jpg)
Next Week’s ReadingsNext Week’s Readings
• McPeek & Keller: effects of superior colliculus inactivation
on target selection
• Bichot & Schall: responsiveness of FEF to target similarity
and history
• Sheinberg & Logothetis: inferotemporal cortex and natural
target selection of familiar objects