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

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

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

16. Predictions

17. Results Behavioural Data

18. Results *significant main effect

20. 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

21. Methodology Imaging Task

22. Predictions

23. 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

24. Epoch Sequence Low WM load and face incongruent High WM load and face incongruent Low WM load and face absent High WM load and face absent Run1Run2Run3Run4Run5Run6 5 memory trials and 15 attention displays } Block Design

25. Results Imaging Data

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

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

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

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

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

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

32. The End

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

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

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