One's Interoception Affects the Representation of Seeing Others' Pain: A Randomized Controlled qEEG Study

Abstract

Objective: This research demonstrates that interoceptive attentiveness (IA) can modulate cortical oscillations related to the emotional and cognitive representations of observing pain in others.

Methods: Twenty participants were required to observe painful/nonpainful stimuli in an individual versus the interactive condition during the recording of the electroencephalogram. The sample was divided into experimental (EXP) and control (CTR) groups, and the EXP group was explicitly required to direct the attention on its interoceptive correlates while observing the stimuli.

Results: Mixed repeated measures, analyses of variance, were applied to each EEG frequency band. Significant findings were obtained mainly for theta and beta bands for the two groups. A hemispheric lateralisation effect was found, with right lateralisation of the theta band for the EXP group when observing painful stimuli and enhanced left activation of theta and beta bands for the CTR group when observing nonpainful stimuli. For both groups, frontal cortical regions were significantly sensitive to social scenarios, while posterior parietal activation was found for stimuli depicting the individual condition.

Conclusions: The results suggest that IA might enhance the emotional representation of painful stimuli, highlighting their negative and unpleasant features in the EXP group, while the attention of the CTR group was mainly drawn to nonpainful stimuli in social and individual conditions, with a positive valence. The role of frontal regions in the processing of social stimuli through social cognition, inducing emotional mirroring and requiring deeper analysis of the social context, was underlined. We propose that IA could be trained for promoting emotion regulation and empathic response.

Figure 1

Samples of stimuli used in the study for painful (left) and nonpainful (right) stimulation in the (a) individual condition and (b) social condition.

Figure 2

CONSORT flow chart.

Figure 3

Delta band. The bar chart shows the higher presence of delta power values in frontal brain regions for both groups. In the chart, bars represent ±1 SE; all asterisks mark statistically significant differences, with p ≤ 0.05. Abbreviations. ROI: region of interest; F: frontal; TC: temporo-central; PO: parieto-occipital.

Figure 4

Theta band. (a) Bar charts show theta power mean values in the EXP group. (b) Theta power representation for the EXP group. The red area represents the increase of theta power in the right hemisphere for painful stimuli, with a frontal activation for the social condition (left head) and a parieto-occipital increase for the individual condition (right head). (c) Bar charts show theta power mean values in the CTR group. (d) Theta power representation for the CTR group. The red area represents the increase of theta power for nonpainful stimuli, with a right frontal activation for the social condition (left head) and a left parieto-occipital activation for the individual condition (right head). For all charts, bars represent ±1 SE; all asterisks mark statistically significant differences, with p ≤ 0.05. Abbreviations. EXP: experimental group; CTR: control group; F: frontal; TC: temporo-central; PO: parieto-occipital; Ind: individual condition; Soc: social condition; pain: painful stimuli; no pain: nonpainful stimuli.

Figure 5

Alpha band. The bar graph shows the higher presence of alpha power values in parieto-occipital brain regions for both groups. In the chart, bars represent ±1 SE; all asterisks mark statistically significant differences, with p ≤ 0.05. Abbreviations. ROI: region of interest; F: frontal; TC: temporo-central; PO: parieto-occipital.

Figure 6

Beta band. (a) Bar charts show beta power lateralisation in the two groups. (b) Beta power representation for the EXP and the CTR group. The red area represents the increase of beta power mean values in the left hemisphere for CTR compared to EXP. (c) Bar charts show beta power mean values in the CTR group. (d) Beta power representation for the CTR group. The red area represents the increase of beta power in frontal areas for nonpainful stimuli in the social condition (left head), and in parieto-occipital areas for nonpainful stimuli in the individual condition (right head). For all charts, bars represent ±1 SE; all asterisks mark statistically significant differences, with p ≤ 0.05. Abbreviations. EXP: experimental group; CTR: control group; F: frontal; TC: temporo-central; PO: parieto-occipital; Ind: individual condition; Soc: social condition; pain: painful stimuli; no pain: nonpainful stimuli.