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

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

structural vs. functional

brain imaging techniques

CTMRI

PETfMRI

CT scan• x-ray & sensor• low resolution

computerized axial tomography

CT scan

reveals tumor or vascular damage

MRIhigh resolution, noisy, NO metal!

magnetic resonance imaging

structural imaging comparison

• radiation risk• low resolution

• no metal, noisy, claustrophobic• high resolution

CT SCAN MRI

PET scanpositron emission tomography

• low resolution (both temporal & spatial)

• radioactive sugar is injected

• expensive due to cyclotron

PET scanpositron 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

• radiation risk• low resolution• cost

• no metal, noisy, claustrophobic• low res but higher than PET

PET SCAN fMRI

psychophysiological techniques(surface recordings)

“psychophysiology”

vs“physiological psychology”

EEG

psychophysiological

techniques

EOG

EMG

“electrophysiology”

= electro-myograph

= electro-oculograph

= electro-encephalograph

EEGelectroencephalography

• poor spatial resolution but excellent temporal resolution (activation)

• record of electrical activity below each electrode

EEG brainwaves characterize mental states

ERPevent related potentials:

• derived from EEG

• waves produced in response to some event are averaged together

• an ERP signal emerges as random “noise” cancels out

startle response & P300

EMGelectromyograph

MEGmagnetoencephalography

• like EEG but magnetic fields

• good spatial and excellent temporal res

SCRskin conductance/resistance

index of physiological arousal

TMStranscranial magnetic stimulation

• new, poorly understood

• produces a temporary “lesion”

• inactivates a brain area

heart rate

psychophysiological techniques

blood pressure

skin response

“polygraph”

pupil dilationsympathetic

nervoussystem

Minor incidents everyone is guilty of:

control question test

• Have you ever hurt someone else’s feelings?

• Have you ever lied to a friend?

• Do you ever exceed the speed limit?

CONTROL QUESTIONS

About the crime being investigated:

control question test

• 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?

RELEVANT QUESTIONS

lie detection

INNOCENT

CONTROL QCRIME RELEVANT Q

GUILTY

CONTROL QCRIME RELEVANT Q

psychophysiological techniques

“false positives”

vs

“false negatives”

Why should you care about “lie detectors”?

discussion

court

employee screeninggovernment jobslaw enforcementarmored security

psychophysiological techniques

“psychopathy”

vs

“psychopathology”