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Reading Hidden Intentions in the Human Brain

Reading Hidden Intentions in the Human Brain. John-Dylan Haynes, Katsuyuki Sakai, Geraint Rees, Sam Gilbert, Chris Frith, and Richard E. Passingham. Tae Hyuk Keum. Introduction. Goal-related processing increases activity in prefrontal cortex

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Reading Hidden Intentions in the Human Brain

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  1. Reading Hidden Intentions in the Human Brain John-Dylan Haynes,Katsuyuki Sakai, Geraint Rees, Sam Gilbert, Chris Frith, and Richard E. Passingham Tae Hyuk Keum

  2. Introduction • Goal-related processing increases activity in prefrontal cortex • frontopolar, lateral, medial, and prefrontal cortex

  3. Introduction • Previous studies proposed: • Preparation of motor responses • Holding a set of potential choices in mind • Tracking memory of previous choices • General processes for establishing a new task • What is unclear: • - Whether the increase in prefrontal activity • encode a subject’s current intention

  4. Hypothesis/Aim • Prefrontalcortex possibly encodes information currently being prepared by a subject • Use choice-delay-response task to see if it is possible to decodefrom activity in prefrontalcortex which task the subjects were covertlyintending to perform

  5. Experiment • Participants: • 3 Male, 5 Female • Age (21 ~ 35) • All right-handed • Had normal vision or corrected vision acuity • Choice-delay-response task • - 8 scanning runs (32 trials each) • - fMRI 3T

  6. Experiment + or - 2 correct 2 wrong 2.8 ~ 10.7s 2s

  7. Experiment • Decoding analysis • Searchlight approach • Multivariate pattern recognition • Classification according to the typical response pattern • Voxel-by-voxel analysis to create 3D spatial map according to decoding accuracy

  8. Results Green: intention coded during delay Red: intention coded during execution

  9. Results • MPFCa activity: - significantly high decoding accuracy only during delay (covert intention) - overall increase during delay • MPFCp activity informative during task execution but not delay • No difference in both intentions (+,-) for overall activity other than spatial patterns

  10. ? Discussion • MPFCa encode goals during preparation • MPFCp encode goals during execution • MPFC contain localizable task-specific representations of chosen intentions (shown for 1st time) • Two intentions are coded not by increase in global activity, but by spatial response patterns

  11. ? • Strengths • Subjects rarely chose wrong answer (5%) • Complex/systematic fMRI analysis • Fine-grained neural representations • Very well controlled • Variable delay • Randomized response positions • No covert motor preparations • Limitations • - Unable to separate motor preparations from encoding of intentions during execution period • - Rapid pacing of trials • -cannot analyze period prior to cued selection • - Experiment is quite long (32 trials X 8 runs)

  12. ? Future studies • Is MPFC generally involved in encoding task-specific intentions or for +/- specifically? • Possible to decode which task is chosen before being aware of choosing it? • Do regions of PFC have clustered functional specializations?

  13. ? References

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