Supplementary Material
Marusak et al., 2014
Data Supplement for Marusak, Martin, Etkin, and Thomason, Childhood trauma
exposure disrupts the automatic regulation of emotional processing,
Neuropsychopharmacology
Methods
Participant Demographics
The present sample of low-income, urban, minority youth was chosen based on
high sociodemographic risk. Prior research shows that minority, urban residents are
nearly two times more likely to develop emotional psychopathology following trauma
exposure (Gillespie et al, 2009; Goldmann et al, 2011; Kessler et al, 1995). In addition,
trauma frequency is extreme among African Americans living in impoverished areas
(nearly 90%; Gillespie et al, 2009). Despite this population’s apparent increased
susceptibility to stress, little research has examined trauma and its neural correlates in
high-risk, urban residents.
Reward Sensitivity
To examine individual differences in RS, we focused on the Behavioral Activation
System (BAS) component of the BIS/BAS scales (Carver and White, 1994). The BAS is
comprised of three subscales: drive, fun seeking, and reward responsiveness. These
subscales are intercorrelated (r’s > 0.3, p’s ≤ 0.05 in the present sample), but relate to
discrete aspects of reward behavior. BASdrive captures the strength with which reward
outcome guides subsequent behavior, and has been used as a measure of trait rewardseeking (Hickey et al, 2010). BASfun seeking is akin to trait novelty-seeking, whereas reward
responsiveness (BASrr) indexes the degree to which a person derives pleasure from
reward. We tested each of the BAS subdimensions, as well as a combination of the
three (Garner et al, 2012) using z-scores to form an overall index of RS.
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Marusak et al., 2014
Experimental paradigm
The task consisted of 163 presentations of happy or fearful facial expression
photographs, overlaid with the words “FEAR” or “HAPPY” to create emotionally
congruent and incongruent stimuli (see Fig.1). Participants were instructed to indicate
the facial affect with a button press response, while trying to ignore the task-irrelevant
word stimuli. Stimuli were presented for 1,000 ms, with a varying interstimulus interval of
2,000-4,000 ms (mean = 3,000 ms), in a pseudorandom order, counterbalanced across
trial types for expression, word, response button, and gender. Participants were given a
practice task before entering the scanner. Stimuli were presented with EPrime software
v.2.0 (Psychology Software Tools, Inc., Pittsburgh, PA) during functional MRI (fMRI)
scanning and displayed on a back-projection screen that was viewed by the participants
via a mirror attached to the head coil. Task duration was 12:46.
Imaging Data Analysis
All fMRI data were processed using SPM8 software (Statistical Parametric
Mapping; http://www.fil.ion.ucl.ac.uk/spm/) implemented in MATLAB (MathWorks, Inc.,
Natick, MA). The first four image volumes were excluded from analysis to allow for signal
equilibration effects. Preprocessing steps included: (i) image realignment, (ii) spatial
transformation to the Montreal Neurological Institute (MNI) template using the
participant-specific transformation parameters created by fitting mean functional images
to the single reference EPI standard template (in SPM). Data were not resampled during
normalization, thus retained the native resolution (3.44 x 3.44 x 4 mm) for subsequent
analysis. (iii) Images were then spatially smoothed with a Gaussian kernel of 6 mm full
width at half maximum.
A 128-second temporal high-pass filter was applied to the data, and temporal
autocorrelation was estimated using a first-order autoregressive model. Two
independent participant-level models were created in the context of a general linear
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Marusak et al., 2014
model to examine effects of (1) conflict and (2) conflict regulation. In the first model,
separate regressors for the stimulus events (convolved with a canonical hemodynamic
response function) were created for incongruent (I) and congruent (C) trials. 82
experimental trials were incongruent, and 81 were congruent. For the second model, trial
types were broken down based on the preceding trial type: regressors were created for
postcongruent incongruent trials (cI), postincongruent incongruent trials (iI),
postcongruent congruent trials (cC), and postincongruent congruent trials (iC). There
were 38 cI trials, 44 cC trials, 37 iC trials, and 44 iI trials. All participant-level models
included regressors of no interest corresponding to the six motion parameters, and
modeled error and posterror trials separately. Participant-level contrasts isolated (1)
conflict-related neural activity by comparing I-C trials, and (2) conflict regulation by
comparing iI-cI trials.
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Marusak et al., 2014
Table S1. Behavioral effects of task congruency.
ACC (%)
RT (ms)
Trial type
M
SD
M
SD
Congruent (C)
86.91
10.63
859.39
171.18
Incongruent (I)
77.99
15.09
898.19
186.96
Abbreviations: ACC, accuracy; RT, reaction time; mean, M; standard
deviation, SD.
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Table S2. Group Differences in Whole-Brain Activity During the Emotional Conflict Task.
peak
Contrast
Brain Region
BA
x
y
z volume (voxels) T-score
Conflict (I-C)
trauma > comparison
L cerebellum
n/a
-36 -76 -24
18
3.08
R midbrain
n/a
14 -12
-8
59
3.21
L midbrain
n/a
-18 -16 -12
57
3.35
L middle occipital gyrus
37
-38 -70
8
338
3.52
R middle temporal gyrus
41
38 -48
4
41
3.5
R primary visual cortex
19
26 -64
4
53
3.2
R middle occipital gyrus
19
38 -70
6
19
3.52
R middle occipital gyrus
19
44 -80 10
116
3.44
L middle occipital gyrus
19
-26 -82 20
243
3.39
L cuneus
19
-2
-92 26
40
3.29
R superior occipital gyrus
19
20 -90 30
59
3.29
L middle frontal gyrus
6
-28 -12 42
32
3.16
L precentral gyrus
6
-49
-4
48
24
3.18
L paracentral lobule
7
14 -42 54
25
3.09
comparison > trauma
no voxels survived at this threshold
Conflict regulation (iI-cI)
trauma > comparison
L lingual gyrus
18
-20 -92 -18
265
3.68
R lingual gyrus
17
6 -100 2
851
5.19
L superior occipital lobe
17
-22 -82
6
15
3.03
L superior temporal lobe
40
-54 -30 18
37
3.4
L superior occipital lobe
19
-26 -88 22
42
3.03
L middle temporal gyrus
39
-30 -62 24
22
3.04
L middle occipital gyrus
?
-30 -74 32
35
3.18
R cuneus
19
6
-86 32
13
3.01
L middle frontal gyrus
9
-46 30
38
26
3.42
R middle frontal gyrus
9
48
32
40
14
3.25
R precuneus
7
6
-84 42
12
3.04
R precentral gyrus
6
38
-8
56
76
3.91
L middle frontal gyrus
6
-44
6
56
42
3.84
L superior frontal gyrus
6
-26
-4
68
168
4.05
comparison > trauma
no voxels survived at this threshold
Whole-brain results provided at p < 0.005 uncorrected, cluster minimum = 10 voxels. Abbreviations:
BA, Brodmann's Area; L, left; R, right; I-C, incongruent minus congruent; iI-cI, postincongruent
incongruent minus postcongruent incongruent. Coordinates given in MNI convention
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