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Attention, Binding, and Consciousness
1. Perceptual binding, dynamic binding2. Neural Correlates of Consciousness:
Binocular rivalry 3. Attention vs. consciousness4. Binding revisited:
Split-brain, split-consciousness
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Asingleintegrated whole:theintrinsicunity
ofconsciousexperience
WHATUNITYOFCONSCIOUSNESS?
MikeGazzaniga1967
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“…let not thy left hand know what thy right hand doeth.”Matthew 6:3
Multitasking:splittingtheattentionalbottleneck
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Inter-hemispheric interference
Serialsearch— inparallel!
SPLIT-BRAIN<700ms
WHOLE-BRAIN~700ms
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Theleft-hemisphereinterpreter
establishesarunning
narrativeand
self-concept
Whydidyoupickthosepictures?“Ohthat’ssimple.Thechickenclawgoeswiththechicken,Andyouneedashoveltocleanoutthechickenshed.
Hemispheric specialization
Leftisbetterat• Speaking, language• Problem solving, planning,
intelligence• Interpretation,
hypothesizing, story-making, confabulation
• Voluntary smiling, top-down attention
Rightisbetterat• Pattern matching• Face recognition• Perceptual grouping/illusory
contours• 3D drawing• Being veridical• Global attention
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Conclusions from split-brain studies
• Although the right hemisphere has very limited verbal abilities, surgically separating the hemispheres appear to result in two independent consciousnesses, one in each hemisphere: split-brain, split consciousness.
• This result does not conflict with the observation or claim that consciousness is an intrinsically unified state.
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Consciousness Conclusions• We seek the NCC—the minimal brain events
sufficient for a conscious percept.
• Conscious awareness may be associated with neural synchrony and/or the firing of small groups of neurons in higher-order sensory areas like IT and STS.
• Ultimately our theory of consciousness should relate it consistently to other phenomena described by science.
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Perceptual decisions and the Diffusion model
1. Area MT and motion perception2. Area LIP and evidence accumulation
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Motion in pref. direction
Motion in null direction
Motion in pref. direction
Motion in null direction
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Motion in pref. direction
Motion in null direction
Area under curve:For 12.8% correlation…area is almost the whole square.
For 0.8% saturation…area is half of total square.
MTcellscarryinfoaboutvisualmotion:
strongermotion,betterinfo
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1. Area MT and motion perception2. Area LIP and evidence accumulation
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Perceptual decisions and the Diffusion model
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Diffusionmodelofaperceptualdecision
I.e.integratesthedifference betweenevidenceforandagainstchoiceA
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Probabilityofpredictingthemonkey’schoicebasedonLIPcellfiringalsorampsup
MTleft=solidblackMTright=grayfilledLIP=redline=timeintegralofMTdifference
LIPneuronastemporalintegrator