Neuroimaging review as therapeutic application for use in assessing interventions to relearn from traumatic memories

1. Brain Imaging & Imagining
James M. DeCarli, MPH, MPA, CHES
jdecarli@ph.lacounty.gov

2. Overview
• Background
– Review brain imaging
techniques
– Strengths & weaknesses of
each
• Neural Foundations of Imagery
• Key Imaging Study
– Evidence that seeing and
imagining are the same to the
brain
• Additional Supportive Imagery
Studies

3. Background
• Brief Review of Imaging Techniques
– Structural Imaging
• X-Ray
• Computerized Tomography (CT) Scan
• Magnetic Resonance Imaging (MRI ) Scan
– Functional Imaging
• Positron Emission Tomography (PET)
• Functional Magnetic Resonance Imaging (fMRI)
• Single Photon Emission Computerized Tomography ( SPECT)

4. Positron Emission Tomography
(PET)
• PET measures emissions
from radioactively labeled
chemicals that have been
injected into the
bloodstream
• Uses this data to produce
two- or three-dimensional
images of the distribution
of the chemicals
throughout the brain and
body.

5. Positron Emission Tomography
(PET)
Strengths
• Moderate accuracy of
localization
• Provides image of brain
activity
• Chemical specificity
• Not subject to magnetic
artifacts
• Quiet -- verbal responses
allowed, motion not as
devastating to analysis
Weaknesses
• Expensive to use
• Radioactive material used
• Invasive
• Low time resolution (>1-
minute)

6. Magnetic Resonance Imaging (MRI)
• MRI uses magnetic
fields and radio
waves to produce
high-quality two- or
three dimensional
images of brain
structures without
injecting
radioactive tracers

7. Magnetic Resonance Imaging (MRI)
Strengths
• No X-rays or radioactive
material is used
• Provides detailed view of the
brain in different dimensions
• Safe, painless, non-invasive
• No special preparation is
required from the patient
(except the removal of all
metal objects)
• Patients can eat or drink
anything before the procedure
Weaknesses
• Expensive to use
• Cannot be used in patients
with metallic devices, like
pacemakers
• Cannot be used with
uncooperative patients
because the patient must lie
still
• Cannot be used with patients
who are claustrophobic (afraid
of small places). However,
new MRI systems with a more
open design are now available

8. Functional MRI (fMRI)
• Functional magnetic
resonance imaging
(fMRI) uses
magnetic resonance
imaging to measure
the quick, tiny
metabolic changes
that take place in an
active part of the
brain

9. Functional MRI (fMRI)
Strengths
• Cheaper, more accessible
• Better spatial and
temporal resolution
• Noninvasive
• Does not require
injections of radioactive
isotopes
• Imaging of oxygen
Weaknesses
• Low time resolution
(around 8-seconds)
• Poor anatomical definition
• Movement sensitive

10. Neural Foundations of Imagery
• Stephen Kosslyn (Key researcher on Imagery)
– Defines Imagery as a basic form of cognition
– Plays a central role in numerous human activities
• Problem solving
• Navigation to memory
– Imagery occurs when perceptual information is
retrieved from long-term memory
• Results in subjective impression of “seeing with the mind’s
eye” (Kosslyn, 2004)

11. Neural Foundations of Imagery
• Neuroimaging techniques (PET, MRI,
fMRI, etc.) provide effective methods:
• Test theory of imagery on humans
• Imaging studies suggest
– Mental imagery draw on the same neural functions as
perception
– Engages similar mechanisms used in memory, motor
control and emotion

12. Imagery Study
• Kosslyn, et al (2004)
• Assessed the degree of shared neural
processing in visual mental imagery and
visual perception

13. Imagery Study
Methodology
• Subjects:
– 20 volunteers
• 8 male
• 12 female
• Mean age 21 years
– Normal or corrected-
to-normal vision
– Right handed
– No history of
neurological disease
• Scanning Procedures:
– Standard fMRI
• Stimuli
– 96 line drawings of
common objects
– Two sets
• Imagery Scans
• Perception Scans

14. Imagery Study
Imagery Scan
• Subjects asked to
close eyes
• Room lights off
• Subjects presented by
auditory probe, with a
name of a picture
– Asked to generate the
corresponding visual
mental image

15. Imagery Study
Perception Scan
• Subjects asked to
keep eyes open
• Room lights on
• Subjects presented
auditory probe with
a line drawing of the
named object shown
on a screen after
the auditory probe

16. Imagery Study
Performance Results
• Subjects pressed one of
two keys in response to
the probe, then asked not
to press the key if not
understood
• No responses
– 20.6% imagery missed
– 5.2% perception missed
• Responses
– 96.2 imagery
– 97.3 perception
0
20
40
60
80
100
120
No Response Response
Imagery
Perception

17. Imagery Study
fMRI Results
• Various brain regions activated
– visual perception
– visual imagery
• Pattern of activation in both imagery and perception
were similar
– However similarity was not uniform across brain regions
• Similarity
– Greatest
• Frontal & parietal cortex
– Smallest
• Occipital cortex

18. Imagery Study
Imagery & Perceptual Activation Results
in Frontal Cortex
Reliable Activation
(Positive Changes)
Negative Activation
(Negative Changes)
Overlap
•Inferior frontal gyrus
•Middle frontal gyrus
•Superior frontal gyrus
•Medial frontal gyrus
•Insular cortex
•Precentral gyrus
•Anterior cingulate gyrus
•Medial frontal cortex
•Superior frontal cortex
•Anterior cingulate
•In all frontal
areas

19. Sagital View:
Illustrates
position of
each section
Grey area:
(Z score)
Significant
overlap
Activation
Map:
Coronal
sections of
the brain

20. Imagery Study
Imagery & Perceptual Activation Results
in Parietal Cortex
Reliable Activation
(Positive Changes)
Negative Activation
(Negative Changes)
Overlap
•Left angular gyrus
•Supramarginal gyrus
–Inferior parietal
lobule
•Superior parietal
lobule
•Precuneus
•Postcentral gyrus
•Middle cingulate
•Posterior cingulate
•Right supramarginal
gyrus
• Precuneus
•Left angular gyrus
•Supramarginal gyrus
•Inferior parietal
lobule
•Superior parietal
lobule
•Postcentral gyrus

21. Sagital View:
Illustrates
position of
each section
Grey area:
(Z score)
Significant
overlap
Activation
Map:
Pattern of
similarity
in parietal
&
temporal
regions

22. Imagery Study
Imagery & Perceptual Activation Results
in Temporal Cortex
Reliable Activation
(Positive Changes)
Negative Activation
(Negative Changes)
Overlap
•Fusiform gyrus
•Parahippocampal gyrus
•Inferior temporal gyrus
•Middle temporal gyrus
•Superior temporal gyrus
•Transverse temporal gyrus
•Right middle temporal
gyrus
•Right superior
temporal gyrus
• Transverse
temporal gyrus
•Superior
temporal gyrus
•Left middle
temporal gyrus

23. Sagital View:
Illustrates
position of
each section
Activation
Map:
Pattern of
similarity in
parietal &
occipital
regions
Grey area:
(Z score)
Significant
overlap

24. Kosslyn’s Conclusion
• Results suggest that visual images &
visual perception draw on similar neural
regions
• Overlap is not uniform:
– “Visual imagery & visual perception appear to
engage frontal and parietal regions” more
similarly than occipital and temporal regions
• Indicates that “cognitive control processes function
similarly in both imagery and perception”

25. Additional Brain Imaging &
Imagery Studies
• Preston, et al (2002)
• Investigated neural substrates of cognitive empathy by using
emotional imagery paradigm
• Subjects: 11
• Procedure: PET
• Stimuli: Subjects imagined an emotional experience (fear of anger)
from their past or a hypothetical situation form another subject
• Results: Similar brain activation between personal and hypothetical
imagery

26. Additional Brain Imaging &
Imagery Studies
• O’Craven & Kanwisher (2000)
• Tested if specific regions of the extrastriate cortex activated during
mental imagery depend on the content of the image
• Subjects: 8
• Procedure: fMRI
• Stimuli: Photographs of faces and familiar places via imagery &
perception scans
• Results:
– Imagery and perception share common processing neural
mechanisms
– Specific brain regions activated during mental imagery depend on
the content of visual image

27. Additional Brain Imaging &
Imagery Studies
• Downs, et al (1999)
• Examined neural mechanisms involved in imagined self-rotation in a task
that involved spatially updating the positions of objects
• Subjects: 10
• Procedure: fMRI
• Stimuli:
– Before scanning: Memorize positions of 4-objects
– During scan:
• 1) no visual input,
• 2) test question-“rotate 90?, what’s on the right?”
• 3) Control question-“rotate 0?, what’s on the right”
• Results: Imagined self-movement involves many of the same brain areas as
physical-movement

28. Summary
• Function imaging techniques, such as PET and fMRI have made it
possible to demonstrate that specific brain regions are activated
similarly between:
– Visual imagery & visual perception
– Fear & hypothetical emotions
– Imagined rotations of self & objects
• Application
– While Stephen Kosslyn studies find that 90% of the brain
regions used for imagining visual images are the same ones
used in actually seeing them:
• Therapeutic application (due to many psychological
approaches integrating visualization as a way of healing):
– Relearning from traumatic memories
– Flooding to heal phobias