1. BISTABILITY & HYSTERESIS IN SUBJECTIVE VERTICAL Bram Bielen Natuurwetenschappen Ministage (40 dagen)

2. Subjective Visual Vertical (SVV) What is up?

3. Systematic error in visual vertical classic interpretation

4. Aubert effect (A-effect) SVV deviates in the direction of head tilt. (Underestimation of body tilt).

5. Müller effect (E-effect) SVV deviates in the direction of feet tilt. (Overestimation of body tilt).

6. Effects illustrated

7. ClockWise (CW) & CounterClockWise (CCW) CWCCW (ρ) Rear View

8. Task Adjustment, what is vertical?

9. Static experiments

10. Subjects are rotated to an angle (ρ) between 0 and 360º, CW or CCW. Testing begins after final tilt angle is reached. Examples: 30 sec / 60 sec.

11. Typical static test result * CW O CCW

12. Dynamic experiments

13. Subject is rotated for two full cycles 720 o CW or CCW. Testing during rotation. Stimulus at 3 sec interval

14. Dynamic test result

15. Bistability

16. Two types of response possible At larger tilt angles

17. Bistability illustrated 180902700360 o A-cluster Δ E-cluster

18. Hysteresis

19. Response depends on direction of preceding rotation LP & SP

20. Hysteresis illustrated

21. Research

22. Why? Different results dynamic and static experiments

23. Test Paradigm Continuous & limited static dynamic

24. Task What is the orientation of a line?

25. Static results ContinuousLimited

26. Static results ContinuousLimited

27. Static results ContinuousLimited

28. Dynamic results + CCW o CW

29. Dynamic results + CCW o CW

30. Conclusions Verification of bistability and hysteresis Bistability in dynamic data

31. What to do? More subjects Different angles Other paradigms Bayesian model

32. Any questions?