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x-ray. radiation passed thru object and onto a photographic plate. brain imaging techniques. structural vs. functional . CT MRI. PET fMRI. CT scan. computerized axial tomography. x-ray & sensor low resolution . CT scan. reveals tumor or vascular damage. MRI.
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x-ray radiation passed thru object and onto a photographic plate
brain imaging techniques structural vs. functional CT MRI PET fMRI
CT scan computerized axial tomography • x-ray & sensor • low resolution
CT scan reveals tumor or vascular damage
MRI magnetic resonance imaging high resolution, noisy, NO metal!
structural imaging comparison CT SCAN MRI • radiation risk • low resolution • no metal, noisy, claustrophobic • high resolution
PET scan positron emission tomography • low resolution • (both temporal & spatial) • radioactive sugar is injected • expensive due to cyclotron
PET scan positron emission tomography
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
functional imaging comparison fMRI PET SCAN • no metal, noisy, claustrophobic • low res but higher than PET • radiation risk • low resolution • cost
psychophysiological techniques (surface recordings) “physiological psychology” vs “psychophysiology”
psychophysiological techniques “electrophysiology” EEG = electro-encephalograph = electro-oculograph EOG EMG = electro-myograph
EEG electroencephalography • poor spatial resolution but excellent temporal resolution (activation) • record of electrical activity below each electrode
EEG brainwaves characterize mental states
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
EMG electromyograph
MEG magnetoencephalography • like EEG but magnetic fields • good spatial and excellent temporal res
SCR skin conductance/resistance index of physiological arousal
TMS transcranial magnetic stimulation • new, poorly understood • produces a temporary “lesion” • inactivates a brain area
psychophysiological techniques pupil dilation sympathetic nervous system heart rate blood pressure skin response “polygraph”
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?
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?
lie detection INNOCENT CONTROL Q CRIME RELEVANT Q GUILTY CONTROL Q CRIME RELEVANT Q
psychophysiological techniques “false positives” vs “false negatives”
discussion Why should you care about “lie detectors”? court employee screening government jobs law enforcement armored security
psychophysiological techniques “psychopathy” vs “psychopathology”