fmri correlates of comprehending real-world events tatiana sitnikova, ph.d. 1,2,4 alexis coty 1,2,4...
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FMRI CORRELATES OF COMPREHENDING
REAL-WORLD EVENTS
Tatiana Sitnikova, Ph.D.1,2,4
Alexis Coty1,2,4
Daphne Robakis1,2,4
Phillip J. Holcomb, Ph.D.5
Gina R. Kuperberg, M.D., Ph.D.2,3,4
W. Caroline West, Ph.D.1,2,4
1 Dept of Neurology, 2 Martinos Center for Biomedical Imaging, 3 Dept of Psychiatry, Mass Gen Hosp, Boston, MA, USA4 Harvard Med Sch, Boston, MA, USA 5 Dept of Psychology, Tufts Univ, Medford, MA, USA
Introduction
How do we use visual information to comprehend real-world events?
• Static pictures Naturalistic video clips
• Paradigm: Contextual anomalies
anomalous ending
Contextual Anomaly Paradigm with Videos
c o n t e x t
congruous ending
congruous ending
anomalous ending
Introduction: Electrophysiological Findings
-2µV
400 800 1200 1600 ms
N400 effect
LPC effect
congruous final sceneanomalous final scene
Cz
Pz
Stimuli
• 40 congruous and 40 anomalous videos: context 6 s long final scene 2 s long
Stimuli: Congruous Videoclick in the middle of the slide to see the video
Stimuli: Anomalous Videoclick in the middle of the slide to see the video
Methods• 16 participants, mean age 21
• Pseudorandom stimulus presentation including
fixation trials
• Counterbalanced design
• 3T Siemens MR scanner
• Event-related fMRI:
TR 2 s, TE 25 ms, 33 slices, 3 mm skip 1 mm
Talairach and spherical space
Timecourse of Hemodynamic Response
xcx
time (s)0 6 10 20 30
% s
igna
l cha
nge
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-0.1
0
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1
-8 -4 0 4 8 12 16 20 24 28
Results: Summed Activity between 10 – 18 s
in the Left Hemisphere
xcx anomalous vs. congruous
BA 9
BA 44, 45
congruous vs. fixation
p=10-4
p=.03
Results: Anatomical Regions of Interest
xcx
left posterior-lateral temporalleft inferior-frontal gyrus
Results: Anatomical Regions of Interest
xcx
anomalous vs. congruousaverage activity 10 - 18 sleft hemisphere
p=.03 p=10-4
left posterior-lateral temporal
-0.2
-0.1
0
0.1
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-8 -4 0 4 8 12 16 20 24 28
time (s)10 20 30
% s
igna
l cha
nge
solid – congruent; dotted - anomalous
0.9
0.6
0.3
Results: Anatomical Regions of Interest
xcx
anomalous vs. congruousaverage activity 10 - 18 sleft hemisphere
left inferior frontal (BA 44, 45)
p=.03 p=10-4-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
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0.8
0.9
-8 -4 0 4 8 12 16 20 24 28
solid – congruent; dotted - anomalous
time (s)
0.9
0.6
0.3
10 20 30%
sig
nal c
hang
e
left caudate
Results: Anatomical Regions of Interest
xcx
anomalous vs. congruousaverage activity 10 - 18 s
p=.03 p=10-4
- 0 . 2
- 0 . 1
0
0 . 1
0 . 2
0 . 3
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0 . 9
-8 -4 0 4 8 12 16 20 24 28
solid – congruent; dotted - anomalous
time (s)
0.9
0.6
0.3
10 20 30%
sig
nal c
hang
e
Discussion: How do fMRI and electrophysiological findings
in language and visual real-world events tie together?
Anomalies in language and videos
Common brain activations
Common electrophysiology
Temporal cortexInferior-frontal cortex
Basal ganglia
N400LPC
Future Directions
• Understanding cognitive functions of these brain regions
• Understanding the flow of information between these regions
Higher-level visual comprehension
Conclusion
A wide neural network
-0.2
-0.1
0
0.1
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-8 -4 0 4 8 12 16 20 24 28
left inferior frontal (BA 44, 45)left caudate
left posterior-lateral temporal
Results: Anatomical Regions of Interest
xcx
Solid – congruent; dotted - anomalous
anomalous vs. congruousaverage activity 10 - 18 sleft hemisphere
time (s)
0.9
0.6
0.3
10 20 30%
sig
nal c
hang
ep=.03 p=10-4