Behavioural data, illustrated separately for each experimental condition (H50, H100, T50, T100).

<p>Upper half: Subjective ratings on the dimensions arousal, valence, anxiety, and authenticity. Higher values indicate higher arousal, but positive valence. Lower half: Skin conductance data (range-corrected values). Error bars indicate the standard error of mean (SEM). #NS.SCR: mean number of non-stimulus specific skin conductance reactions; AMP.NS.SCR: mean amplitude of non-stimulus specific skin conductance reactions. * p < 0.05. ** p < 0.01</p

PPI results for the contrast heart > tone; seed region: right insula (x = 39, y = 15, z = 3).

<p><i>Note</i>. Significance threshold: p < 0.01 (uncorrected); minimum cluster size: 10 voxels.</p><p>PPI results for the contrast heart > tone; seed region: right insula (x = 39, y = 15, z = 3).</p

Behavioural data, illustrated separately for each experimental condition (H50, H100, T50, T100).

<p>Upper half: Subjective ratings on the dimensions arousal, valence, anxiety, and authenticity. Higher values indicate higher arousal, but positive valence. Lower half: Skin conductance data (range-corrected values). Error bars indicate the standard error of mean (SEM). #NS.SCR: mean number of non-stimulus specific skin conductance reactions; AMP.NS.SCR: mean amplitude of non-stimulus specific skin conductance reactions. * p < 0.05. ** p < 0.01</p

Demographic characteristics and questionnaire scores of the sample.

<p><i>Note</i>. Means and Standard Deviations are reported, except for the variables “Female gender” and “Smoking”. ASI = Anxiety Sensitivity Index; BDI II = Beck Depression Inventory II.</p><p>Means (SD) except where noted.</p

Correlation analyses.

<p>Scatterplots display correlations between the estimated beta values in the right anterior insular cortex (MNI coordinates (x = 39, y = 15, z = 3)) and AMP.NS.SCR (range-corrected) in response to H100 (a), subjective arousal ratings for H100 (b), and the Anxiety Sensitivity Index (c). Pearson correlation coefficients (R) are given in the plots. Estimated ß-values for the four regressors of interest (H50, H100, T50, T100) were extracted and added so that the t-contrast H50+H100 > T50+T100 was replicated, i.e. difference values were entered into correlation analyses. ** p < 0.01 (Bonferroni-corrected).</p

Design of the heartbeat paradigm.

<p>Upper half: Illustration of the block design structure (four conditions with four blocks of stimulation each, separated by 30 s baseline periods). Order of blocks was randomized across subjects. Lower half: Temporal sequence within one condition, using the example of the heartbeat condition. Hearts illustrate the heartbeat condition; clefs illustrate the sinus tone condition.</p