1
ACC for both groups by thresholding stimulus-induced activation in the liminal state. Compared with controls, IBS patients' salience network demonstrated significant overlapping with the DMN and ECN in the prefrontal and posterior cingulate cortices (Fig. 1B). An excessive coupling of the salience network with other intrinsic networks can invokes more extensive attentional and cognitive processing of incoming sensory stimuli across brain networks. Therefore, our results suggest a link between the observed excessive coupling of the salience network with the DMN and ECN and the neural expression of visceral hypersensi- tivity in IBS patients. In a more general theoretical context, the findings support the theory that aberrant functional connectivity of the salience network may underline various attentional and cognitive disorders in human subjects. Tu1802 Patients With Irritable Bowel Syndrome Show Sex Related Differences in Resting-State Functional Connectivity Jui-Yang Hong, Jennifer S. Labus, Lisa A. Kilpatrick, Jean Stains, Nuwanthi Heendeniya, Suzanne R. Smith, David Katibian, Kirsten Tillisch, Emeran A. Mayer Background: Resting-state functional MRI has been widely used to investigate intrinsic brain connectivity in healthy and patient populations, including those with chronic pain. The anterior insula cortex (aINS) with its ventral (affective) and dorsal (cognitive) subregions is a major hub in the saliency network. Sex-related differences in the brain frequency power distribution of aINS have recently been reported in irritable bowel syndrome (IBS), a disorder more prevalent in women (Hong et al, 2013). However, the aINS functional connectivity of sex differences in IBS has not been investigated. Aims: 1. To characterize the intrinsic connectivity of subregions of aINS between age-matched female and male patients with IBS and healthy controls (HCs). 2. To examine the possible sex and disease related alterations in the functional connectivity of aINS. Methods: 48 Rome III positive IBS patients (24 males) and 48 age-matched HCs (24 males) were recruited. Images were acquired with echo planar sequence on a Siemens 3 Tesla Trio scanner. The aINS was manually delineated into dorsal and ventral parts based on Destrieux Atlas. The individual seed-to-voxel connectivity map was created in the CONN fMRI connectivity toolbox. The component-based noise correction method was used to remove confounds and head movement. Imaging data was bandpass filtered 0.008-0.08 Hz. 4 mm-smoothed Fisher transformed bivariate correlation maps were implemented in SPM8. A second-level random effects full factorial model specified the four groups as factors. Regions considered significant were corrected for multiple comparisons at the whole-brain cluster-level using FWE correction at a threshold of p<0.05. Results: In the left hemisphere, male IBS had increased dorsal aINS connectivity to several prefrontal regions (medial frontal cortex, dorsal lateral prefrontal cortex and inferior orbital frontal cortex [OFC]) when compared to female IBS. These regions were comprised within the default mode, executive and saliency networks, respectively. Male IBS also showed increased connectivity between left ventral aINS and inferior OFC compared to female IBS. In the right hemisphere, male IBS had greater ventral aINS connectivity to inferior and medial OFC compared to female IBS. There were no significant differences between IBS subjects and HCs when males and females were combined in each group, and no differences between male and female HCs. Conclusion: In the absence of any stimulus, IBS subjects showed sex-specific and hemisphere-related alterations in functional connectivity between aINS subregions and prefrontal/orbitofrontal brain regions, consistent with differences in the executive/saliency network between male and female patients. These findings are also consis- tent with previous observations from evoked brain responses of greater prefrontal modulation in male IBS patients. Tu1803 Influence of Extraversion on Brain Activity During Rest, Pain Anticipation and Visceral Pain Processing James K. Ruffle, Steven J. Coen, Adam D. Farmer, Michiko Kano, Vincent Gampietro, Steve Williams, Qasim Aziz BACKGROUND & AIMS: Eysenck proposed ‘trait theory' of personality, where the dimen- sions extraversion (degree of optimism and sociability) and neuroticism (degree of anxiety and fear) encompass numerous individual qualities. Whilst the influence of neuroticism on the brain processing of pain is well studied, the role of extraversion in pain processing remains to be investigated and thus this was the aim of our study using functional magnetic resonance imaging (fMRI). METHODS: 33 healthy volunteers participated in the study, all of whom consented in writing (17 male; mean age 29, range 20-53, all right handed). Extraversion was measured using the Eysenck Personality Questionnaire. fMRI data was acquired using a 3T GE MRI scanner during rest, anticipation of pain, and painful distal oesophageal balloon distention. During fMRI, 480 T2* weighted images per slice (40x3mm slices, 0.3 interslice gap, TE 30ms, TR 2500ms, flip angle 80°, matrix size 642, sum of images per scan = 19,200) were captured to illustrate blood oxygen level dependent (BOLD) contrast during the different experimental events. The effects of extraversion on fMRI response during these events were subsequently determined using ANOVA brain activation mapping analyses within XBAM, a statistical package of image processing and statistical inference. RESULTS: There was a diversity of extraversion scores (range 6-22), to which it did not influence pain threshold or rating. High extraversion was associated with significantly greater activity in the left cuneus (Brodmann Area (BA) 18) during rest (p<0.001) and the right S-847 AGA Abstracts insula (BA13) during both anticipation (p<0.0002) and pain (p<0.0008). Low extraversion was associated with significantly greater brain activity in numerous regions during pain anticipation, including the bilateral precuneus (BA31), bilateral lingual gyrus (BA18) and the right inferior temporal gyrus (p<0.0001). CONCLUSIONS: Our results suggest that the brain processing of pain can be influenced by the personality dimension of extraversion and therefore like other personality dimensions such as neuroticism, extraversion should be controlled for in brain imaging studies of pain in health and disease. Brain Regions Significantly More Active in the High Extraversion Group Size of activated clusters represents the number of voxels. Coordinates (x, y, z) listed above are as per (Talairach & Tournoux, 1988), expressed in millimeters. The given coordinates represent the point of maximum activity (highest median response) in each cluster. Clusters are determined by cluster mass statistics, and therefore do not have size limitations. Abbrevia- tions: BA, Brodmann area. Brain Regions Significantly More Active in the Low Extraversion Group Size of activated clusters represents the number of voxels. Coordinates (x, y, z) listed above are as per (Talairach & Tournoux, 1988), expressed in millimeters. The given coordinates represent the point of maximum activity (highest median response) in each cluster. Clusters are determined by cluster mass statistics, and therefore do not have size limitations. Abbrevia- tions: BA, Brodmann area. Tu1804 Resting and Guided Thinking State Functional Connectivity of the Thalamus With the Insula and Cingulate Cortex in Cyclic Vomiting Syndrome Erica A. Samuel, Mark Kern, Robert M. Siwiec, Arash Babaei, Andrew S. Nencka, Thangam Venkatesan, Reza Shaker BACKGROUND: Cyclic Vomiting Syndrome (CVS) is a disorder characterized by discrete episodes of nausea and emesis interspersed with symptom free periods. Emotional stressors have been found to play a role in triggering CVS symptoms. Thalamo-insular and thalamo- cingulate pathways may contribute to the etiology of this finding as they are known to be members of the interoceptive network. AIM: To characterize the effect of negative emotional stimulation (NES) on thalamo-cingulate (TCC) and thalamo-insular functional connectivity (TIC) in CVS patients and healthy controls (HC). METHODS: Ten Rome III positive CVS patients (6F, ages 19-49, average length of disease 11 years) in their inter-episodic phase and 10 HC (6F, ages 21-54) were studied. Functional MRI (fMRI) data was collected during two 10-minute scanning periods (TR 2 s, 3.5 mm isotropic voxels, 64x64 matrix, 240 mm FOV, 3.5 mm slice thickness and 41 contiguous slices). The first was a resting state and the second 10-minute scan was a guided thinking state scan after volunteers viewed 3 minutes of pictures with a negative valence from a standardized picture database. Analysis of Functional Neuroimages software and the afni_proc.py python script was used for analysis. A spherical 2.5 mm radius seed was placed within each posterior thalamic nuclei: right (R) and left (L) ventral posterior lateral (VPL), R and L ventral posterior medial (VPM), and R and L lateral posterior (LP). The average time series was extracted across each seed and a Pearson cross correlation coefficient (CC) was calculated. The connectivity was assessed between each thalamic nuclei and the cingulate and insula and was compared using an unpaired t-test. A p<0.05 was corrected for multiple comparisons. RESULTS: Group analysis demonstrated differences in resting state connectivity between the two groups. However, emotional stress had different outcomes within the CVS patients than in the HC. Both the TIC and TCC were altered by NES in HC. However, NES did not alter TIC in CVS patients. HC showed significant differences between the R VPM at the L dorsal anterior insula, the L VPL and the left dorsal anterior insula and L middle cingulate cortex (MCC) (Figure 1). CVS patients showed significant differences between the R LP and the R anterior cingulate AGA Abstracts
