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Role of Working Memory in Visual Selective Attention

Role of Working Memory in Visual Selective Attention. de Fockert, Rees, Frith, Lavie (2001). Outline. Definition of Selective Attention Definition of Working Memory Previous research Current research Methodology & Results Behavioural Task Imaging Study Discussion. Selective Attention.

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Role of Working Memory in Visual Selective Attention

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  1. Role of Working Memory in Visual Selective Attention de Fockert, Rees, Frith, Lavie (2001)

  2. Outline • Definition of Selective Attention • Definition of Working Memory • Previous research • Current research • Methodology & Results • Behavioural Task • Imaging Study • Discussion

  3. Selective Attention • A system that focuses on relevant information by filtering out irrelevant information from the available stimuli • The purpose is to reduce the load on cognitive processing systems Downing, 2000

  4. Working Memory • A system used for short-term storage & “executive processes” Smith & Jonides, 1999

  5. Short-term Memory • Performing active maintenance of a limited amount of information for a matter of seconds Smith & Jonides, 1999

  6. Executive Processes • Attention & Inhibition (Competition) • Task Management • Planning • Monitoring • Coding Smith & Jonides, 1999

  7. Attention & Inhibition Task Management Planning Monitoring & Updating Coding Low Working Memory Load *adapted from Smith & Jonides, 1999

  8. High Working Memory Load Attention & Inhibition Task Management Planning Monitoring & Updating Coding

  9. Working Memory Load As working memory load increases, processing of irrelevant stimuli also increases, and vice versa.

  10. Previous Research • Working memory may provide top-down modulation of selective attention • Active maintenance of objects in working memory caused selective attention to shift towards that object Downing, 2001

  11. LeBar et al (1999) • Physiological overlap between working memory and visuospatial attention tasks • Concluded that spatial attention and working memory use common cognitive features • This would require dynamic shifting of attentional resources

  12. Current Paper

  13. Hypothesis • Selective Attention relies on Working Memory to prioritize stimuli to process relevant stimuli *BUT if Working Memory is busy than Selective Attention will process irrelevant stimuli to a greater degree

  14. Methodology Behavioural Task

  15. 500 ms 1500 ms 850 ms 500 ms 1250 ms Response Interval 500 ms 1250 ms Response Interval 3000 ms Example of High Working Memory Load condition with two Selective Attention tasks.

  16. Predictions

  17. Results Behavioural Data

  18. Results *significant main effect

  19. Distractor Interference/Congruency Effects • Low working memory load = 46 ms (error rate=3%) • High working memory load = 78 ms (error rate=4%) • F(1,9) = 13.36, P<0.01

  20. Methodology Imaging Task

  21. Predictions

  22. Details • 6 participants (4 males, 2 females) • 2T Siemens VISION system measured BOLD signal • 32 contiguous 3-mm axial slices per volume • Acquired every 2800 ms • Total of 720 volumes acquired in six runs

  23. Run1 Run2 Run3 Run4 Run5 Run6 Low WM load and face incongruent High WM load and face absent High WM load and face incongruent Low WM load and face absent Epoch Sequence } Block Design 5 memory trials and 15 attention displays

  24. Results Imaging Data

  25. Precentral gyrus Superior temporal gyrus Inferior frontal gyrus Significant activations related to Working Memory Load- LH

  26. Superior parietal lobe Precentral gyrus Superior temporal gyrus Significant activations related to Working Memory Load- RH

  27. Significant activations related to the interaction between selective attention and working memory load include: • Bilateral fusiform gyri • Right inferior occipital lobe • Left lingual gyrus

  28. Occipitotemporal gyrus (Fusiform gyrus) (bilateral) Lingual gyrus (left) Occipital Lobe (right) Low WM Significant activations related to the interaction High WM

  29. Percent signal change for face presence versus absence • Graph represents the maxima of interaction in right fusiform gyrus, separated by working memory load

  30. Discussion • It is concluded that working memory and the prefrontal cortex plays an important role in controlling selective attention

  31. The End

  32. Perceptual vs Working Memory Load Perceptual Load As perceptual load increases, processing of irrelevant stimuli decreases, and vice versa.

  33. Previous Work • Physiological overlap between areas involved in working memory and interference resolution (Binge et al, 2001)

  34. Analysis using SPM • Voxel-based • Images are spatially normalised into standard space and smoothed

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