Supplementary Methods and Results
Methods
Participants
Forty-three female participants were recruited, 16 euthymic bipolar disorder (BD) patients, 13
borderline personality disorder (BPD) patients and 14 healthy controls. Participants were
recruited through the CADE Clinic (www.cadeclinic.com) at Royal North Shore Hospital and via
advertisements. The study was approved by the Human Research Ethics Committee at Royal
North Shore Hospital (Sydney, Australia) and all participants completed informed consent prior
to participation. All participants underwent a structured clinical interview by the psychiatrist
(GSM) to determine whether they met DSM-IV criteria for BD or BPD and were currently
euthymic. Healthy controls were also assessed to ensure the absence of unusual symptoms and
any psychiatric history.
Participants who were not currently euthymic, hospital inpatients, abusing substances, or who
had a history of traumatic head injury, neurological illness (eg, seizures or stroke), learning or
developmental disorders, or were not proficient in English were excluded from the study. All
participants were instructed to refrain from alcohol or recreational drug use 24 hours prior to the
brain scan and from caffeine or nicotine within one hour of the scan.
Questionnaires
A series of questionnaires about mood, emotion regulation, childhood trauma, and schemas were
administered: 1) The Depression Anxiety Stress Scales1 (DASS); 2) The Difficulties in Emotion
Regulation Scale2 (DERS); 3) The Emotion Amplification and Reduction Scale3 (TEARS); 4)
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The Childhood Trauma Questionnaire4 (CTQ); 5) The NEO Five-Factor Inventory5, 6 (NEO-FFI)
which measures the five main domains of personality; 6) the Self Report Manic Inventory7
(SRMI). The Weschler Test of Adult Reading8 (WTAR) was also administered as a measure of
premorbid intelligence.
Behavioral Task
The emotional Stroop task was programmed using Presentation software
(http://www.neurobs.com). Participants viewed a series of 72 words (24 positive, 24 negative
and 24 neutral) from the Affective Norms for English Words (ANEW) manual9. The emotional
words were selected carefully so that they held semantic salience to each patient group and
evoked powerful responses. Based on the ANEW norms for females9, the words were selected so
that the mean valence for the negative, positive and neutral words were 2.0, 8.2, and 5.1,
respectively. The level of arousal was comparable across positive and negative words with mean
arousal ratings for negative, positive, and neutral words were 6.1, 6.3, and 3.8, respectively.
Further words were matched for number of syllables in each valence condition.
Words were displayed in a 16sec block consisting of eight words. Six blocks of each valence
were presented, alternating with baseline blocks of non-words (****) over two functional runs.
Each word was presented for 1500ms, followed by an average 500ms (250-750ms) interstimulus interval (black screen). Words were not repeated, and the order of blocks was
counterbalanced. Words and non-words were displayed in one of four colors red, blue, yellow
and green and participants were instructed to indicate the color of the word as quickly and as
accurately as possible by pressing one of four buttons. Reaction time and accuracy of responses
were also obtained.
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MRI data acquisition
Imaging datasets (structural and functional) were acquired on a 3T Siemens Magnetom Trio
Scanner at the Advanced Research and Clinical High-field Imaging (ARCHI) facility of the
University of Sydney. A T2*-weighted gradient echo echo planner imaging (EPI) sequence (29
axial slices, slice thickness 4mm with 1mm gap, TR=2000ms, TE=35ms, flip=70o, 64 × 64
matrix) was used to acquire functional data. A high resolution T1-weighted structural image was
also acquired for precise localization of brain activity using a magnetisation prepared rapid
gradient echo (MPRAGE) sequence (TR=1570ms, TE=3.22ms, Flip=15o, matrix 256 x 256, 192
slices). To minimize head movement during scanning, the head was restrained using foam pads
inserted on each side.
fMRI data analysis
Data analyses were carried out using SPM5 software
(http://www.fil.ion.ucl.ac.uk/spm/software/spm5). Each subject’s functional and structural
images were first inspected visually for scanner artifacts and gross anatomical abnormalities, and
then re-oriented so that the origin of the image lay within 3cm of the anterior commissure.
Functional images were realigned, corrected for slice time variation, and were spatially
normalized to a common stereotactic space using the Montreal Neurological Institute (MNI) EPI
template. Finally, the functional images were spatially smoothed with a Gaussian kernel of 8mm3
full width at half maximum.
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Using the general linear model framework10, each experimental condition (positive, negative,
and neutral) was modelled with a box-car function convolved with a canonical hemodynamic
response function. In order to remove low-frequency confounds, data were high-pass filtered
(128sec) and temporal correlation was modelled using a first-order autoregressive model (AR1).
The experimental contrast was created by subtracting the neutral condition from the emotion
(positive + negative) condition and analysed in a subsequent random effects model.
Analyses were carried out within a priori anatomical regions of interest (ROIs). To investigate
lateral and medial prefrontal neural activity the inferior, middle, superior, and medial prefrontal
cortices including the anterior cingulate cortex (ACC) were chosen along with amygdala and
hippocampus. Regional masks were created using the WFU_Pickatlas11.
In order to ensure that the Stroop task recruited ROIs, the experimental contrast (emot-neut)
from all subjects was entered into a second level random effects analysis (one-sample t-test).
Activity was considered significant using a threshold of p < 0.05 (corrected for multiple
comparisons using false discovery rate, FDR) and a cluster size of 20voxels. Differences
between groups in ROI activity was determined using a one-way ANOVA, an uncorrected
threshold of p < 0.05, and a cluster size of 20voxels.
Correlation Analyses
Percentage BOLD signal change during the presentation of emotional words compared to neutral
words was calculated from the clusters of voxels where patient groups displayed similar and
differential pattern of neural activity (such as in the right ventrolateral prefrontal cortex (vl-PFC),
left dorsolateral prefrontal cortex (dl-PFC), medial prefrontal cortex (m-PFC), and amygdala
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(Ag)) using the MarsBaR Toolbox (http://marsbar.sourceforge.net). These changes from all
participants were then correlated with the total scores of DERS.
5
Clinical Data Analysis
Clinical data was analyzed using PASW Statistics Version 19. A series of One-Way Analyses of
Variance (ANOVA) for continuous data was used to compare the BD, BPD, and healthy control
groups. Potential confounds such as age, years of education, premorbid IQ, childhood trauma
history, and number of psychiatric medications, were explored first and then differences between
groups on self-report measures of mood, emotional dysregulation, and personality were
examined.
Where significant results of ANOVA were found, post-hoc analyses were conducted and the
Scheffè procedure was applied for multiple comparisons. An initial alpha level of 0.05 was used
for all statistical tests.
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Results
Demographic
Table 1: ANOVA results for demographic data and questionnaires.
BPD
BD
Healthy
Controls
Mean (SD)
Mean (SD)
Mean (SD)
32(7.9)
35.6(10.7)
31.2(11.1)
F(2,40) = .84
0.439
Years of Education
14.6(2.4)
15.9(1.5)
15.4(1.9)
F(2,39) = 1.44
0.249
Number Psychiatric Meds
1.4(1.2)
1.6(1.1)
0(0)
F(2,42) = 11.47
0.000
WTAR Standard Score
116(5.8)
117(6.9)
117(5.7)
F(2,38) = .16
0.376
54.8(6.7)
55.4(8.5)
51.3(7.0)
F(2,37) = .86
0.755
DASS Total Score
26.5 (12.4)
15.0 (9.7)
6.8 (5.1)
F(2, 40) = 14.33
0.000
DASS Depression
9.7 (6.7)
4.4 (4.8)
2.1 (2.7)
F(2, 40) = 8.26
0.000
Neuroticism
38.1(8.9)
30.6 (4.8)
17.4 (6.2)
F(2, 37) = 25.56
0.000
DERS Total Score
130.0 (18.6)
89.6 (19.6)
68.8 (17.5)
F(2, 40) = 37.9
0.000
TEARS Total Score
37.6 (7.7)
43.8 (6.9)
47.8 (7.6)
F(2, 40) = 6.61
0.003
SRMI Total Score
16.2 (5.1)
11.2 (8.6)
8.9 (6.7)
F(2, 40) = 3.87
0.029
Measure
Age (years)
CTQ (Total Score)
Statistics
F-Statistic
p-value
Questionnaires
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fMRI Findings:
Table 2: Summary of brain regions where bipolar disorder (BD) and borderline
personality disorder (BPD) patients displayed different neural activity compared to healthy
controls (HC).
Regions
Cluster
MNI co-ords
voxel
Size
x,y,z (mm)
equivZ
Healthy Controls (HC) vs Bipolar Patients (BD)
HC> BD
Frontal regions
dl-PFC extending to vl-PFC
dl-PFC
BD> HC
Frontal regions
dm-PFC
vl-PFC
263
171
-32 46 4
-28 - 4 44
2.68
2.94
156
67
90
-16 44 30
12 50 30
46 36 -10
2.89
2.14
2.49
Healthy Controls (HC) vs Borderline Patients (BPD)
HC> BPD
Frontal regions
dl-PFC
Limbic regions
Ag extending to Hi
BPD> HC
Frontal regions
vl-PFC
452
139
-34 34 34
34 38 38
3.45
2.28
98
36 -18 -20
2.91
102
329
44 36 -8
-42 38 -6
2.6
2.56
Abbreviation Used: Prefrontal Cortex (PFC), dorsolateral (dl), ventrolateral (vl), dorsomedial
(dm), Amygdala (Ag), Hippocampus (Hi)
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