Educing Information: Interrogation - National Intelligence University

eye movements, and mechanical movements of the body that occur in conjunction
with heartbeat and breathing. Subjects must remove all magnetic material, such as
watches, jewelry, and eyeglasses, to prevent these types of movement artifacts.
The results of the study discussed in this section suggest that further MEG
studies may assist in understanding the role of memory within the evolving
set of candidate neural subsystems (discussed elsewhere in the Neurological
Mechanisms subsections) involved in the generation of deception. However,
given the apparent lack of published studies on MEG and deception, it is clear
that MEG is not yet ready for deployment.
Positron Emission Tomography (PET)
Positron emission tomography (PET) is a nuclear medicine medical
imaging technique. The first human PET scanner was developed in 1973. A PET
scanner produces a three-dimensional image of functional brain activity. First,
a radiolabeled positron emitting tracer is injected into a subject’s bloodstream.
This tracer stays in the bloodstream and moves via circulation. Blood flows at
different rates in the brain depending on the level and location of neural activity.
Areas of higher blood flow will contain a larger amount of radioactive tracer,
and will therefore emit a stronger signal. This signal is measured by the PET
scanner, which scans slices of the brain. The images of these slices are then used
to compare the distribution of radioactivity, thus allowing a nuclear medicine
physician or radiologist to map the changes in regional cerebral blood flow (rCBF)
that accompany changes in neuronal activity.
To date, only one study has been conducted using PET to measure brain
activity during deception (Abe et al., 2005). In this study, subjects viewed
photographs related to experienced and unexperienced events. In one deception
condition, subjects were instructed to lie in response to the photos of experienced
events: that is, they were to pretend not to know the experienced event. In the
other deception condition, subjects were instructed to lie in response to the photos
of unexperienced events: that is, they were to pretend to know the unexperienced
event. During both types of deception, the dorsolateral, ventrolateral, and medial
prefrontal cortices were active. The anterior cingulate cortex was active only
during the deception condition in which subjects were pretending not to know.
Activation of the dorsolateral and ventrolateral cortices and the anterior
cingulate cortex support the findings of several functional magnetic resonance
imaging (fMRI—see section below) studies of deception (Langleben et al., 2002;
Ganis et al., 2003; Kozel et al., 2004a,b). However, there is some conflict between
this PET study and previous fMRI studies in regard to the laterality of dorsolateral
prefrontal cortex activation. The PET study showed significant activation in the
left hemisphere, whereas Kozel et al. (2004a) reported activation in the right
hemisphere, Lee et al. (2002) in the bilateral hemisphere, Kozel et al. (2004b)
in the more anterior part of the prefrontal cortex with right dominance, and
Ganis et al. (2003) reported bilateral activation. It is possible that this conflict is
due to the different experimental designs used in these studies; however, these
conflicts clearly indicate the need for more neuroimaging studies of deception.
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