Diagrammatical representation of the experimental paradigm.

<p>(A) Perception trial Note: 1. A nociceptive stimulus #5 (S1) was delivered to the participant’s lateral malleolus coupled with a low-pitched tone which both lasted for 50 ms. 2. The participant perceived the stimulus for 3,000 ms and maintained the image. 3. A nociceptive stimulus #5 (S2) was delivered to the site for 50 ms; 4. The participant was to respond by stating whether S2 would have been at the same intensity level to that of the nociceptive image maintained during the 3000 ms (Pe1); the participant should respond “yes.” 5. The participant rated the nociceptive image from S1 on an 11-point NRS. (B) Imagery trial Note: 1. A nociceptive stimulus #5 (S1) was delivered to the participant’s lateral malleolus coupled with a high-pitched tone, which both lasted for 50 ms. 2. The participant generated a sub-nociceptive image #5 (Im1) and mentally rehearsed the sub-nociceptive image for 3,000 ms. 3. A sub-nociceptive stimulus #3 (S’1) was delivered to the site for 50 ms. 4. The participant was to respond by stating whether S’1 would have been at the same intensity level to that of Im1; the participant should respond “no.” 5. The participant rated the nociceptive image from S1 on an 11-point NRS.</p

Correlations between the normalized pain NRS on different levels of nociceptive images and the amplitudes of the later ERP components at selected sites (included only those with p<0.05).

<p>Note: All significant level was p<0.05; Normalized Pain NRS = NRS_Imagery–NRS_Perception. Average normalized pain NRS is computed by averaging the ratings across five levels of stimulation.</p><p>No significant correlations were obtained for levels 2 and 4 normalized pain NRS.</p

Numerical rating scale (NRS) ratings of 1 to 5 level nociceptive images in Imagery and Perception conditions.

<p>Note: I – P  =  Differences in NRS ratings between the Imagery and Perception conditions. Standard deviations are in parentheses.</p

Correlations between the normalized pain NRS on different levels of nociceptive images and the Stroop Test scores (included only those with p<0.05).

<p>Note: Normalized Pain NRS = NRS_Imagery–NRS_Perception. Average normalized pain NRS is computed by averaging the normalized pain NRS across five levels of stimulation.</p><p>Key: WR = Word reading; CN = Color Naming; INC = Incongruent color naming. Different scores are computed by subtracting the reaction time score of the earlier from the later test. Proportional scores are computed by dividing the difference scores by the total time of the earlier test.</p>*<p>p<0.05.</p>**<p>p<0.01.</p><p>No significant correlations were obtained for level 2 normalized pain NRS (mostly r <0.40). Only one significant correlation was obtained for level 5 normalized pain NRS with CN Time Error (p = 0.566, p<0.05).</p