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Office Hours Today are Relocated to CCBN. rm EP1216 (the receptionist can help you find me). Feature Integration Theory. What term does Treisman use to describe the bundle of features at a specific location?. Feature Integration Theory.

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Office Hours Today are Relocated to CCBN

rm EP1216 (the receptionist can help you find me)


Feature Integration Theory

  • What term does Treisman use to describe the bundle of features at a specific location?


Feature Integration Theory

  • Object Files are mental (neural?) representations of the features associated with an object

    • whenever an object is selected by attention its features are bound and an object file is opened

    • when the features of that object change, the object file is updated


Feature Integration Theory

  • How did Treisman et al. test whether the visual system uses object files?


Feature Integration Theory

  • Priming: observers are faster to respond to something they’ve just seen


Feature Integration Theory

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Feature Integration Theory

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Feature Integration Theory

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Feature Integration Theory

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Feature Integration Theory

G

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Feature Integration Theory

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Feature Integration Theory

What Letter?


Feature Integration Theory

  • What was the result?


Feature Integration Theory

  • What was the result?

    • Naming was faster if the prime occurred in the same object, even though the object had moved


Feature Integration Theory

  • What was the result?

    • Naming was faster if the prime occurred in the same object, even though the object had moved

  • Interpretation?


Feature Integration Theory

  • What was the result?

    • Naming was faster if the prime occurred in the same object, even though the object had moved

  • Interpretation?

    • visual system establishes object files and updates them as the location and features of the object change


The Physiology of Attention


Physiology of Attention

  • Neural systems involved in orienting

  • Neural correlates of selection


Disorders of Orienting

  • Lesions to parietal cortex can produce some strange behavioural consequences

Parietal

Lobe


Disorders of Orienting

  • Lesions to parietal cortex can produce some strange behavioural consequences

    • patients fail to notice events on the contralesional side

    • Patients behave as if they are blind in the contralesional hemifield


Disorders of Orienting

  • Lesions to parietal cortex can produce some strange behavioural consequences

    • patients fail to notice events on the contralesional side

    • Patients behave as if they are blind in the contralesional hemifield but they are not blind

  • Called Hemispatial Neglect


Disorders of Orienting

  • Patients will often “neglect” half of their visual field


Disorders of Orienting

  • Hypothesis: Parietal cortex somehow involved in orienting attention into contralesional space


Disorders of Orienting

  • Posner and colleagues

    • Use cue-target paradigm to investigate attentional abilities of parietal lesion patients


Disorders of Orienting

  • Posner and colleagues

    • Use cue-target paradigm to investigate attentional abilities of parietal lesion patients

    • Prediction ?


Disorders of Orienting

  • Posner and colleagues

    • Use cue-target paradigm to investigate attentional abilities of parietal lesion patients

    • Prediction: stimuli in ipsilesional field always faster than stimuli in contralesional field and cues don’t matter


Disorders of Orienting

A PREDICTION:

invalid - contralesional target

valid - contralesional target

invalid - ipsilesional target

valid - ipsilesional target


Disorders of Orienting

invalid- contralesional target

Results: Severe difficulty with invalidly cued contralesional target

invalid - ispilesional target

valid - contralesional target

valid - ipsilesional target

Results: Valid cue in contralesional field is effective


Disorders of Orienting

  • Interpretation:

    • Patients have difficulty disengaging attention from good hemifield so that it can be shifted to contralesional hemifield


Disorders of Orienting

  • Interpretation:

    • Patients have difficulty disengaging attention from good hemifield so that it can be shifted to contralesional hemifield

    • Parietal cortex is somehow involved in disengaging attention


Disorders of Orienting

  • Disengage - Shift - Engage Model

    • Parietal Cortex notices events and disengages attention


Disorders of Orienting

  • Disengage - Shift - Engage Model

    • Parietal Cortex notices events and disengages attention

    • Superior Colliculus moves attention


Disorders of Orienting

  • Disengage - Shift - Engage Model

    • Parietal Cortex notices events and disengages attention

    • Superior Colliculus moves attention

    • Pulvinar Nucleus reengages attention


Disorders of Orienting

  • Disengage - Shift - Engage Model

    • Parietal Cortex notices events and disengages attention

    • Superior Colliculus moves attention

    • Pulvinar Nucleus reengages attention

    • Entire process is under some top-down control from Frontal Cortex


Disorders of Orienting

  • Orienting mechanism can be interfered with in normal brains


Disorders of Orienting

  • Orienting mechanism can be interfered with in normal brains

    • changes that are not accompanied by transients are hard to detect


Disorders of Orienting

  • Orienting mechanism can be interfered with in normal brains

    • changes that are not accompanied by transients are hard to detect

      • e.g. building appearing slowly

      • orienting mechanism scans the scene aimlessly


Disorders of Orienting

  • Orienting mechanism can be interfered with in normal brains

    • changes that are not accompanied by transients are hard to detect

      • e.g. building appearing slowly

      • orienting mechanism scans the scene aimlessly

    • changes accompanied by full-field transients are hard to detect

      • e.g. change blindness

      • orienting mechanism is blinded by the transient


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  • Neural correlates of selective attention


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