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An fMRI study of Anomalous Anticipation of emotional stimuli

An fMRI study of Anomalous Anticipation of emotional stimuli. Dick J. Bierman Universities of Amsterdam & Utrecht (NL). Toward a science of Consciousness Tucson, April 10. 2002. What is Presentiment?.

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An fMRI study of Anomalous Anticipation of emotional stimuli

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  1. An fMRI study of Anomalous Anticipation of emotional stimuli Dick J. Bierman Universities of Amsterdam & Utrecht (NL) Toward a science of Consciousness Tucson, April 10. 2002

  2. What is Presentiment? Consider the sep. 11 WTC attack. Was there anybody in the general public having some uneasy feeling before the attack?

  3. There are a lot of stories….

  4. Was this just coincidence? Ed Cox (1960) Compared train ridership on days with and without a train accident. He found that on accident days there were significant less people on trains. (Note: Utts redid the analyses and found a smaller effect after correction for holidays)

  5. 1996: Empirical Approach: Presentiment experiment Presentiment is reported as the apparent psycho-physiological effect of a future emotional ‘cause’.

  6. Procedure • Subject sits relaxed with electrodes attached • Gets about 40 exposures of randomized neutral and calm stimuli • Skin conductance is averaged separately for emotional and neutral stimuli • Before, during and after stimulus • Baseline fixed at ~ -7.5 seconds

  7. Blank screen Or Calm Subject Hits Button Random!! baseline 5 0 Procedure Presentiment ‘trial’ Skin Conductance Time

  8. stimulus Emotional Presentiment? Calm Results First Subject (Radin-1) Before During After

  9. Presentiment! Results all Subjects (Radin-1) Emotional Calm

  10. This should be everywhere! Main stream emotion research Measure baseline of dependent var Present an emotional / calm event Measure response of dependent var baseline event response time

  11. Mainstream Research questions R = f ( emotional level of event): Find ‘f’ R = Response - BaseLine Implicit assumption: BaseLine is independent of ‘future emotional level’

  12. What did we do? • Search for main stream databases that • Measure a BaseLine for at least 4 seconds. • Use strong emotional events • For which Data can be obtained

  13. What did we find? Hamm group: on the speed with which fear arises in animal phobic patients Damasio group: on implicit emotional learning during Gambling task

  14. 150 msec 7000 msec 6850 msec Fixation stimulus Blank Screen Procedure Animal fear study Skin Conductance time

  15. Erotic presentiment Calm Results re-analysis Hamm’s data stimulus

  16. Draws card Feedback: win or loss Damasio: gambling procedure • Participant gets initially $2000 • Draws cards from one of 4 different decks • Card is either winning or losing Preparation Skin Conductance time

  17. Damasio dataset analyses • Damasio-analysis P = f (type of deck) !!! Advantageous vs non-advantageous • Our Re-analysis: P = f(type of Card) Winning vs Losing

  18. Winning vs. Losing Cards: • Quote from: Bechara, Damasio et al, Science, 275, 28 February 97, 1293-1295 • : ….. “the players have no way of predicting when a penalty will arise…”

  19. Results re-analysis Gambling experiment • t = 1.634; df=117 ; p =0.053 • • Presentiment effect : 20%!!!!

  20. So What Next? • Can we differentiate between different emotions? • Can we exclude possible artefacts? • Can we locate the source of this phenomenon?

  21. Brain scanner, Amsterdam Summer 2001

  22. Event Related Design • 10 subjects • 48 pictures (events) • ~ 16 neutral, ~ 8 erotic, ~ 8 violent • 4.2 seconds exposure time • 16.8 seconds for one trial (= 8 volumescans) • 1 vol: 22 slices, slice resolution: 64 * 64

  23. Analysis procedure (1) • Dependent var: BOLD signal per voxel (Blood Oxygenation Level Dependent) • Pre-processing: • Slice time correction • Linear trend removal • 8 mm spatial smooting • No further smoothing in time domain

  24. Analysis Procedure • General Linear Model • Predictors : neutral stim, erotic stim, violent stim. Results in: • Regions of Interest with significant fit. • Event related averaging over stim.condition • t-test of average BOLD signals in ROI

  25. Contrast between emotional and neutral conditon. Brain regions which have a significant fit with emotional stims and neutral stim as predictor

  26. Event related averaging erotic neutral stimulus Brain-map with ROI’s Plot for BOLDsignal for the whole experiment Erotic Presentiment effect at time: -4 seconds. Td = 2.89 df= 39 p < 0.01

  27. violent ROI: -51, -78, 1 erotic

  28. violent ROI: -1,-80, 37

  29. Amygdala Negative presentiment in neutrals???

  30. Pooling of data • Mapping in Talairachspace • Loss of signal due to individual differences • So:separate male and female

  31. all female All female: Erotic & Violent presentiment (t ~ 1.75, df=158, p<0.05 o.t.)

  32. all male All male: Erotic presentiment (t ~ 2.1, df=226, p<0.01 o.t.)

  33. ‘Normal’ explanations • Chance fluke, weak effects, over analysis • Incorrect Randomization • With replacement • Subject strategies • Introduced by software • Hemodynamic curve • smoothing

  34. Conclusion • This study should be seen as exploratory • Warrants further research • Most fmri emotional pictures research sh/could look at this effect if: • Randomization with replacement • Strong stimuli • Reasonable ISI (~ 18 seconds)

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