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