Table 3.

BOLD responses to experimental stimuli

		IBS						Control						IBS > control
		Cluster			Voxel			Cluster			Voxel			Cluster			Voxel
		k	p(cor)	ROI^0.01	t	p(cor)	x, y, z	k	p(cor)	ROI^0.01	t	p(cor)	x, y, z	k	p(cor)	ROI^0.01	t	p(cor)	x, y, z
45 mmHg increase
Anterior insula	L	620	0.00*	69%	7.61	0.00*	−36, 26, −8	264	0.001	29%	5.63	0.002	−40, 8, 6
	R	540	0.00*	51%	6.16	0.001	38, 24, −12	279	0.001	29%	4.78	0.02	42, 4, 2
Posterior insula	L	371	0.00*	32%	6.78	0.00*	−48, 2, 2	129	0.02	9%	5.65	0.004	−40, 6, 6
	R	320	0.00*	30%	6.05	0.001	48, 4, 0	37	0.14	4%	5.41	0.004	42, 4, 4
Dorsal brainstem	L	130	0.005	38%	5.71	0.001	−6, −42, −24							10	0.17	6%	3.78	0.04	−6, −42, −24
	R	150	0.003	44%	6.04	0.00*	8, −30, −20
ACC dorsal	L	234	0.001	43%	5.35	0.003	−8, 4, 42							51	0.05	10%	3.18	0.17	−8, 12, 42
	R	161	0.003	45%	5.15	0.003	0, 16, 38
45 mmHg decrease
ACC supragenual	L
	R	29	0.14	3%	3.74	0.09	6, 34, 2
ACC infragenual	L	142	0.004	39%	3.92	0.04	−6, 32, −6	116	0.008	32%	3.74	0.05	−6, 44, −4
	R	12	0.16	16%	3.77	0.04	10, 52, −4
25 mmHg increase
Anterior insula	L	545	0.00*	61%	6.14	0.001	−38, 20, −2	245	0.002	28%	5.05	0.007	−32, 28, −6
	R	526	0.00*	50%	5.81	0.002	48, 10, −2	328	0.00*	31%	5.99	0.001	36, 22, 4
Posterior insula	L	211	0.004	15%	5.64	0.003	−48, 2, 0
	R	41	0.13	6%	4.84	0.01	46, 12, −6							28	0.19	4%	4.04	0.06	40, −14, 4
Dorsal brainstem	L	18	0.12	7%	3.65	0.05	−4, −28, −14
	R	53	0.04	15%	4.34	0.01	6, −30, −20
ACC dorsal	L	56	0.05	14%	3.87	0.05	−6, 18, 42
	R	25	0.11	14%	4.12	0.02	6, 8, 28							8	0.21	2%	3.56	0.07	6, 10, 28
25 mmHg decrease
ACC infragenual	L	42	0.06	12%	3.23	0.12	−8, 44, −12	128	0.008	35%	3.66	0.05	−12, 36, −10
	R	53	0.04	15%	5.34	0.002	12, 50, −6	26	0.09	10%	2.97	0.16	6, 52, −4
Amygdala	L	72	0.02	30%	4.39	0.01	−20, −8, −24	6	0.19	3%	3.43	0.07	−28, −12, −14
	R	52	0.04	21%	5.37	0.001	20, −6, −22	31	0.07	13%	3.75	0.04	20, −6, −22
5 mmHg increase
Anterior insula	L	201	0.004	23%	5.04	0.007	−34, 22, 4
	R	252	0.002	24%	4.39	0.03	28, 26, −2
ACC dorsal	L	14	0.18	5%	3.71	0.06	−14, 0, 38
	R
5 mmHg decrease
Amygdala	L	20	0.10	8%	4.46	0.009	−26, −4, −24
	R	5	0.19	2%	3.22	0.09	22, −6, −22
Cue decrease
Anterior insula	L							3	0.46	11%	4.74	0.02	−28, 32, −2
	R							285	0.00*	27%	4.93	0.01	36, 8, 2
Posterior insula	L							218	0.002	22%	4.96	0.02	−46, 0, 8
	R							306	0.00*	28%	5.11	0.009	42, −14, −6	94	0.02	9%	4.33	0.04	40, −10, 6
Dorsal brainstem	L							198	0.001	58%	4.49	0.01	−6, −26, −12	85	0.01	25%	4.01	0.03	−4, −26, −12
	R							118	0.005	34%	4.56	0.01	10, −24, −6	22	0.10	9%	3.76	0.05	4, −30, −24
ACC dorsal	L
	R							31	0.08	7%	3.79	0.05	4, 14, 42
ACC supragenual	L							68	0.04	8%	3.87	0.08	−10, 32, 22
	R							59	0.05	7%	3.62	0.13	2, 30, 24
Amygdala	L							98	0.008	40%	4.24	0.02	−22, −4, −24
	R							9	0.16	4%	3.89	0.09	26, 2, −26

For each region where peak voxel height or the spatial extent volume-corrected p < 0.1 of that cluster, the cluster size (number of voxels) is labeled k, followed by the volume-corrected probability associated with finding a cluster this large or larger [p(cor)]. Because the peak cluster is not always within the largest cluster, the two cluster columns are followed by an additional measure of spatial extent, the total percentage of ROI voxels where p < 0.01 (uncorrected), although there is no accepted statistical test associated with this measure. The three voxel columns present the peak voxel t-score, the volume corrected probability of finding a t-score this large or larger [p(cor)], and location in MNI space. The x, y, z coordinates represent approximate millimeter distances from the anterior commissure (voxel 0 0 0), with positive values to the right, anterior, and superior directions, respectively. Formal group comparisons are presented in the rightmost columns. All these results represent larger BOLD signal in the IBS-C group. It should be noted that this represents a bigger change from the resting baseline state in the control group in ROIs where the primary response to a stimulus was a BOLD decrease. ROI^0.01, Proportion of the region of interest where p < 0.01 (uncorrected). *p < 0.0005.