2010 Bronze Award, Samsung Human Tech Thesis Prize

1. MEG 를 이용한 고등의사결정과정의 시공간적 동역학 연구
Spatiotemporal dynamics of high-level cognitive
decision making: an MEG study
Do economists need brains?
The Economist Jul 24th 2008 1

2. 2

3. Decision making is a very complex and fast process
Decision making is processed on a
millisecond temporal scale in brain
networks.
http://rulebooktothegamesoflife.
wordpress.com/2008/08/25/rps/

4. MEG provides better temporal and spatial resolution
Better temporal resolution
fMRI
(1~2 sec) < MEG / EEG
(~1 msec)
Better spatial resolution
MEG / fMRI
(~1 mm) > EEG
(~1 cm)
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5. MEG analysis process
DLPFC
STG
PC
Data recording Time-frequency analysis Effective connectivity
Source reconstruction analysis
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6. Major novel findings
Four steps of the decision-making process
in the brain
1. Awareness of information
- the γ frequency ranges during the 50 to 100 ms
- OFC (social & emotional)
2. Evaluation of alternatives
- the β and γ frequency ranges during the −600 to −500 ms
- DLPFC (rational), OFC, STG, IPL (theory of mind)
3. Decision making
- the γ frequency range −200~−100 ms
- DLPFC, OFC, IPL, Precuneus (fronto-parietal network)
4. Post-decision evaluation
- the β and γ frequency range 350~500 ms
- STG, MTG, ITG, IPL (mentalizing)
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7. An apt tool to investigate complex decision-making
processes in a laboratory setting: the Ultimatum Game
proposer responder
1. Make an offer: 9:1 2. Conflict btwn emotion & cognition
(send emotional cue) (ACC, Ins, dlPFC, vmPFC)
Reward anticipation (NAcc)
Optimal offer? (ToM)
3. Make a decision
4. Post-decision
evaluation
Game theory: the proposer should offer the smallest amount possible and
the responder should accept any amount offered.
Behavior: Their decision making is dependent on their personal valuation of
fairness. 7

8. 1. Information awareness
Inferior frontal gyrus for emotionally aware information.
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9. PDC - high beta and gamma frequency band (35~50Hz)
Response to
A Unfair offer
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
OFC
STG -800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
Unfair offer is more cognitively demanding to process
PC
Response to
B Fair offer
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
P < 0.05
P < 0.001 -800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
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Decreased information transmission

10. 2. Evaluation of alternatives
- the β and γ frequency ranges during the −600 to −500 ms
- DLPFC (rational), OFC (social & emotional), STG, IPL (theory of mind)
3. Decision making
- the γ frequency range −200~−100 ms
- DLPFC, OFC, IPL, Precuneus (fronto-parietal network)
4. Post-decision evaluation
- the β and γ frequency range 350~500 ms
- STG, MTG, ITG, IPL (mentalizing)
10

11. PDC - high beta and gamma frequency band (20~50Hz)
A Acceptance -800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
DLPFC
STG -800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
PC
B Rejection -800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
P < 0.05
P < 0.001 -800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
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Right DLPFC successfully regulate other regions of the brain in acceptance.

12. Neurobiological insights from
Information transfer (effective connectivity)
between regions in the brain
• Information is processed as discrete sequential
functional microstates.
• It is not assumed that one single neural
population was active during a certain
microstate.
• Many different areas can work in parallel, but
together they form a certain spatial and
temporal configuration.
• MEG spatiotemporal dynamics alone also cannot
provide the large-scale network information that
comes from oscillatory interactions between
spatially distant cortical populations.
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13. Emotion vs. Cognition
Do economists need brains?
The Economist Jul 24th 2008
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