spatiotemporal dynamics of high-level cognitive decision making: an meg study
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2010 Bronze Award, Samsung Human Tech Thesis PrizeTRANSCRIPT
MEG 를 이용한 고등의사결정과정의 시공간적 동역학 연구Spatiotemporal dynamics of high-level cognitive
decision making: an MEG study
Do economists need brains? The Economist Jul 24th 2008 1
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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/
MEG provides better temporal and spatial resolution
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Better temporal resolutionfMRI MEG / EEG(1~2 sec) (~1 msec)<
Better spatial resolutionMEG / fMRI EEG(~1 mm) (~1 cm)>
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DLPFC
STG
PC
MEG analysis process
Data recording Time-frequency analysisSource reconstruction
Effective connectivity analysis
Major novel findings Four steps of the decision-making process
in the brain
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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)
An apt tool to investigate complex decision-making processes in a laboratory setting: the Ultimatum Game
proposer responder
1. Make an offer: 9:1(send emotional cue)Reward anticipation (NAcc)Optimal offer? (ToM)
2. Conflict btwn emotion & cognition(ACC, Ins, dlPFC, vmPFC)
4. Post-decision evaluation
3. Make a decision
responderresponderproposer
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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.
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Inferior frontal gyrus for emotionally aware information.
1. Information awareness
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
-800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
Response toUnfair offer
A
OFC
STG
PC
P < 0.05P < 0.001
Decreased information transmission
PDC - high beta and gamma frequency band (35~50Hz)
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
-800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
Response toFair offerB
fronto (right) ->temporal (left), fronto
Unfair offer is more cognitively demanding to process
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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)
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
-800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
-800 ~ -600 ms -600 ~ -400 ms -400 ~ -200 ms -200 ~ -000 ms
-800 ~ -200 ms -200 ~ -400 ms -400 ~ -600 ms -600 ~ -800 ms
Acceptance
Rejection
DLPFC
STG
PC
P < 0.05P < 0.001
PDC - high beta and gamma frequency band (20~50Hz)
Right DLPFC successfully regulate other regions of the brain in acceptance.
A
B
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Neurobiological insights fromInformation 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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Do economists need brains? The Economist Jul 24th 2008
Emotion vs. Cognition