Interaction of Sensory and Value Information in Decision-Making

1. Interaction of Sensory and Value Information in Decision-Making Institute for Theoretical Physics and Mathematics Tehran January 16, 2006

2. Alan Rorie

3. representation of stimulus/ action value REWARD HISTORY SENSORY INPUT low level sensory analyzers DECISION MECHANISMS motor output structures ADAPTIVE BEHAVIOR

4. SENSORY INPUT low level sensory analyzers representation of stimulus/ action value DECISION MECHANISMS motor output structures REWARD HISTORY ADAPTIVE BEHAVIOR

8. Motion discrimination task with multiple reward conditions. • Monkey must discriminate the direction of the motion. • Differs from the matching task because target values are fixed • Variable coherences span psychophysical threshold, creating a range of difficulties • Creates conflict between sensory and reward information • Only correct choices are rewarded

10. Differ in absolute reward magnitude “Absolute” and “relative” reward magnitude Differ in relative reward magnitude

11. Absolute magnitude No effect on choice T1 T1 T1 T1 T2 T2 T2 T2 Relative magnitude Biases choices n=51 T1 T2 Effect of absolute and relative reward magnitude on behavior

12. We know from behavior: • Absolute magnitude does not influence choices • Relative magnitude influences choices • Motion coherence influences choices We ask: • Whether, and how, absolute magnitude, relative magnitude, and motion coherence are represented in LIP as the decision unfolds in time?

13. Area LIP in the Macaque Brain LIP http://www.loni.ucla.edu/data/monkey • Sensory-based decisions (Shadlen & Newsome, ‘96, ‘01) • Value-based decisions (Sugrue, Corrado & Newsome, ‘04)

14. GO! LIP neurons are spatially selective LIP RESPONSE FIELD

15. GO! LIP neurons are spatially selective LIP RESPONSE FIELD

18. Representation of Absolute Reward Magnitude in LIP n=51

19. Representation of Absolute Reward Magnitude in LIP n=51

20. Representation of Absolute Reward Magnitude in LIP n=51 Chose In

21. Representation of Absolute Reward Magnitude in LIP n=51 Chose In Chose Out

22. Representation of Relative Reward Magnitude in LIP n=51

23. Representation of Relative Reward Magnitude in LIP n=51

24. Representation of Relative Reward Magnitude in LIP n=51 Chose In

25. Representation of Relative Reward Magnitude in LIP n=51 Chose In Chose Out

26. Representation of Relative Reward Magnitude in LIP n=51 Chose In Chose Out

27. Absolute Relative Relative Absolute Absolute Choice Choice Summary of population activity How can we quantify these dynamics?

28. Modeling Dynamics

29. Modeling Dynamics

30. Modeling Dynamics

31. Modeling Dynamics

32. Modeling Dynamics

33. Modeling Dynamics

34. Modeling Dynamics

35. Modeling Dynamics

36. Conclusions: behavior • Absolute reward magnitude does not affect choice • Relative reward magnitude biases choice • Motion coherence biases choice • The biasing effects of relative magnitude and coherence are additive: reward information does not change psychophysical sensitivity to motion coherence (or vice versa).

37. Conclusions: physiology • The representation of sensory and reward information is dynamic; the profile changes dramatically during the course of a trial. • The critical decision variables—relative reward magnitude and motion coherence—are present in LIP at the precise time when the decision is being formed. • Absolute reward magnitude is represented in LIP even though it does not influence choice behavior. • Most single LIP neurons show effects of multiple variables; the representation is multiplexed.

38. Future Directions: • Origins of sensory and reward signals • How are sensory and reward signals cast into a common additive currency for guiding decisions? • Why is the profile of signals in LIP changing so dramatically throughout the trial? What does this imply for the computational strategy embodied in cortical circuitry?

39. Indeed there are now no logical (and I believe no insurmountable technical) barriers to the direct study of the entire chain of neural events that lead from the initial central representation of sensory stimuli…to the detection and discrimination processes themselves, and to the formation of general commands for behavioral responses and detailed instructions for their motor execution. V . B . Mountcastle, Handbook of Physiology, 1985

40. T1 T1 T2 T2 The Optimal Bias

43. 55% 78% 47%