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11 Attention

11 Attention. Introduction. Attention: State of selectively processing simultaneous sources of information Benefits: Performance of behavioral tasks Brain Imaging – changes in cortical activity Behavioral manifestations Visual attention; Auditory attention. Introduction.

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11 Attention

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  1. 11 Attention Psychology 355

  2. Introduction • Attention: State of selectively processing simultaneous sources of information • Benefits: Performance of behavioral tasks • Brain Imaging – changes in cortical activity • Behavioral manifestations Visual attention; Auditory attention Psychology 355

  3. Introduction Functions of attention • Concentrate on one object in visual field • Selectively attend to information (while ignoring other information) • Preferential processing of sensory information Attention-deficit hyperactivity disorder Demonstrates critical nature of intact attentional mechanisms Brain imaging studies Show that cortical activity is altered by attention Psychology 355

  4. Behavioral Attention Visual attention • Move eyes until object imaged on fovea • Shifting attention • Enhanced visual processing 1) Enhanced detection 2) Faster reaction times Psychology 355

  5. Behavioral Attention + -> <- Psychology 355

  6. Behavioral Attention Faster Reaction Times Enhanced Detection Psychology 355

  7. Behavioral Attention Neglect Syndrome as an Attentional Disorder Person ignores objects, people, and their own body to one side of the center of the gaze Psychology 355

  8. Physiological Attention Shifting attention • What happens to neural activity? • What brain areas are involved? Observed in high-level cognitive and numerous sensory arease.g., Area V1 to visual cortical areas in the parietal and temporal lobes Psychology 355

  9. Physiological Attention • Functional MRI Imaging of Attention to Location • Subjects view stimulus • Change location of attended sector • Brain activity shifts retinotopically Psychology 355

  10. Physiological Attention PET Imaging of Attention to Features • Same-different discrimination task • Features: Color, shape, speed • (A) Selective attention: one feature • (B) Divided attention: all features • Subtract B from A shows brain activity associated with attention to one feature Psychology 355

  11. Physiological Attention PET Imaging Attention to Features Speed Color Shape Psychology 355

  12. Physiological Attention Enhanced Neuronal Responses in Parietal Cortex • Attention: Experimental vs. Normal conditions • What happens to attention under normal conditions? • Test the Hypothesis: Attention changes location prior to eye movement • Wurtz, Goldberg, and Robinson: Record neural activity from Posterior Parietal Psychology 355

  13. Physiological Attention Enhanced Neuronal Responses in Parietal Cortex A Posterior parietal cortex neurons B Directing eye movements C Response significantly enhanced neuronal response when eyes went to target Its either an attention shift or a premotor signal Psychology 355

  14. Physiological Attention Receptive Field Changes in Area V4 Psychology 355

  15. How is Attention Directed? • Cortical, subcortical areas • Modulate the activity of neurons in sensory cortex areas • The Pulvinar Nucleus • In humans: Damage to the PN results in slow responses to stimuli on the contralateral side • Muscimol (GABA agonist;suppresses activity) inmonkey PN results in impairment of attention shifting Psychology 355

  16. How is Attention Directed? • Attention and Eye Movements • Eye moves to attended object • Eye movements & attention closely related • Recent experiments • Brain circuitry: Directing eyes to objects of interest • Frontal Eye Fields (FEF) • Cortical area • FEF neurons Psychology 355

  17. How is Attention Directed? Attention and Eye Movements (Cont’d) Experiment • Train monkeys to look at display of small light spots • Place electrode in FEF and determine motor field of neurons at the tip • Small electrical stimulation enhancement? Psychology 355

  18. How is Attention Directed? Attention and Eye Movements (Cont’d) Results FEF involved in directing attention; Enhancing visual performance Conclusion Guidance of attention Integrated with system to move eyes Psychology 355

  19. Concluding Remarks • Studies of attention • Point to flexibility of the human brain • More mental energy to one location • Enhanced sensitivity & reaction time • Ignoring competing stimuli • Need for attention • e.g.,- Cannot process ALL information in area V1 • Selects what information should access the limited processing resources Psychology 355

  20. End of Presentation Psychology 355

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