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Presentation Transcript

  1. x-ray radiation passed thru object and onto a photographic plate

  2. brain imaging techniques structural vs. functional CT MRI PET fMRI

  3. CT scan computerized axial tomography • x-ray & sensor • low resolution

  4. CT scan reveals tumor or vascular damage

  5. MRI magnetic resonance imaging high resolution, noisy, NO metal!

  6. structural imaging comparison CT SCAN MRI • radiation risk • low resolution • no metal, noisy, claustrophobic • high resolution

  7. PET scan positron emission tomography • low resolution • (both temporal & spatial) • radioactive sugar is injected • expensive due to cyclotron

  8. PET scan positron emission tomography

  9. fMRI scan • higher spatial resolution than PET (poor temporal resolution) • 3-D images possible • hemoglobin (blood protein that binds oxygen) changes its magnetic field response

  10. functional imaging comparison fMRI PET SCAN • no metal, noisy, claustrophobic • low res but higher than PET • radiation risk • low resolution • cost

  11. psychophysiological techniques (surface recordings) “physiological psychology” vs “psychophysiology”

  12. psychophysiological techniques “electrophysiology” EEG = electro-encephalograph = electro-oculograph EOG EMG = electro-myograph

  13. EEG electroencephalography • poor spatial resolution but excellent temporal resolution (activation) • record of electrical activity below each electrode

  14. EEG brainwaves characterize mental states

  15. ERP event related potentials: • derived from EEG • waves produced in response to some event are averaged together • an ERP signal emerges as random “noise” cancels out

  16. startle response & P300

  17. EMG electromyograph

  18. MEG magnetoencephalography • like EEG but magnetic fields • good spatial and excellent temporal res

  19. SCR skin conductance/resistance index of physiological arousal

  20. TMS transcranial magnetic stimulation • new, poorly understood • produces a temporary “lesion” • inactivates a brain area

  21. psychophysiological techniques pupil dilation sympathetic nervous system heart rate blood pressure skin response “polygraph”

  22. control question test CONTROL QUESTIONS Minor incidents everyone is guilty of: • Have you ever hurt someone else’s feelings? • Have you ever lied to a friend? • Do you ever exceed the speed limit?

  23. control question test RELEVANT QUESTIONS About the crime being investigated: • Were you at the 1st National Bank on Jan 1? • Did you drive a Ford sedan at the Metro Plaza? • Did you steal $200,000 from the bank?

  24. lie detection INNOCENT CONTROL Q CRIME RELEVANT Q GUILTY CONTROL Q CRIME RELEVANT Q

  25. psychophysiological techniques “false positives” vs “false negatives”

  26. discussion Why should you care about “lie detectors”? court employee screening government jobs law enforcement armored security

  27. psychophysiological techniques “psychopathy” vs “psychopathology”