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Office Hours Today are Relocated to CCBN

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

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  1. Office Hours Today are Relocated to CCBN rm EP1216 (the receptionist can help you find me)

  2. Feature Integration Theory • What term does Treisman use to describe the bundle of features at a specific location?

  3. 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

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

  5. Feature Integration Theory • Priming: observers are faster to respond to something they’ve just seen

  6. Feature Integration Theory +

  7. Feature Integration Theory G + N

  8. Feature Integration Theory +

  9. Feature Integration Theory +

  10. Feature Integration Theory G +

  11. Feature Integration Theory +

  12. Feature Integration Theory What Letter?

  13. Feature Integration Theory • What was the result?

  14. Feature Integration Theory • What was the result? • Naming was faster if the prime occurred in the same object, even though the object had moved

  15. 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?

  16. 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

  17. The Physiology of Attention

  18. Physiology of Attention • Neural systems involved in orienting • Neural correlates of selection

  19. Disorders of Orienting • Lesions to parietal cortex can produce some strange behavioural consequences Parietal Lobe

  20. 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

  21. 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

  22. Disorders of Orienting • Patients will often “neglect” half of their visual field

  23. Disorders of Orienting • Hypothesis: Parietal cortex somehow involved in orienting attention into contralesional space

  24. Disorders of Orienting • Posner and colleagues • Use cue-target paradigm to investigate attentional abilities of parietal lesion patients

  25. Disorders of Orienting • Posner and colleagues • Use cue-target paradigm to investigate attentional abilities of parietal lesion patients • Prediction ?

  26. 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

  27. Disorders of Orienting A PREDICTION: invalid - contralesional target valid - contralesional target invalid - ipsilesional target valid - ipsilesional target

  28. 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

  29. Disorders of Orienting • Interpretation: • Patients have difficulty disengaging attention from good hemifield so that it can be shifted to contralesional hemifield

  30. 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

  31. Disorders of Orienting • Disengage - Shift - Engage Model • Parietal Cortex notices events and disengages attention

  32. Disorders of Orienting • Disengage - Shift - Engage Model • Parietal Cortex notices events and disengages attention • Superior Colliculus moves attention

  33. Disorders of Orienting • Disengage - Shift - Engage Model • Parietal Cortex notices events and disengages attention • Superior Colliculus moves attention • Pulvinar Nucleus reengages attention

  34. 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

  35. Disorders of Orienting • Orienting mechanism can be interfered with in normal brains

  36. Disorders of Orienting • Orienting mechanism can be interfered with in normal brains • changes that are not accompanied by transients are hard to detect

  37. 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

  38. 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

  39. Next Time: • Neural correlates of selective attention

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