Down-modulation of mu-activity through empathic top-down processes

Abstract

Simulation theories argue that humans simulate motor processes of others to gain information about intentions and emotional states of others. Mu-suppression is a valid electrophysiological correlate of these processes. Mu-activity can be measured via electroencephalography (EEG) in the alpha-band (8-13 Hz) above the sensorimotor cortex and is suppressed when actions are executed or observed. Based on a within-subject design, including 28 participants, it was tested whether the processes measured by mu-suppression could be modulated by empathic top-down-processes. Participants were asked to take the perspective of two actors, telling a story about a sad or neutral life event (video sequences). Afterwards, EEG was measured at central (C3, Cz, C4) and occipital (O1, Oz, O2) electrodes, while participants observed the actors drinking water (standardized video sequences, 8 s duration). Fast fourier transformation showed stronger suppression of power in the alpha-range (relative to baseline) at central and occipital electrodes while the actor with the sad story was observed relative to the actor with the neutral story. Furthermore, measures of state empathy correlated positively with the difference of mu-suppression between executed and observed movements, an indicator of self-other discrimination. Thus, mirror neuron activity measured by mu-suppression is modulated by empathic processes.

Enhanced mirroring upon mutual gaze: Multimodal evidence from TMS-assessed corticospinal excitability and the EEG mu rhythm

“…Other TMS studies have indicated that M1 excitability is also modulated by other social factors, such as, amongst others, emotional body language of the actor (Borgomaneri, Vitale, Gazzola, & Avenanti, 2015), social reciprocity (Sartori, Cavallo, Bucchioni, & Castiello, 2012), and the level of observed social interaction (Donne, Enticott, Rinehart, & Fitzgerald, 2011;Hogeveen & Obhi, 2012). Similarly, EEG activity in the mu frequency range has been demonstrated to depend on the extent by which participants are engaged in a social game (Perry, Stein, & Bentin, 2011), the perception of social information such as intentions and emotions (Perry, Troje, & Bentin, 2010) and empathic processes (Hoenen, Schain, & Pause, 2013). Taken together, this subtle and sophisticated adjustment of motor resonance according to the demands of the social context forms an essential competence of humans for flexibly engaging in interpersonal social interactions (Wang & Hamilton, 2012).…”

The impact of mood on empathy for pain: Evidence from an EEG study

“…The mu suppression were subjected to a three‐way repeated measures analysis of variance (ANOVA), Mood (negative, positive, neutral) × Pain (painful, neutral) × Site (C3, Cz, C4). Based on previous studies (Cheng, Chen, & Decety, ; Cheng, Yang et al, 2008; Hoenen, Lübke, & Pause, ; Hoenen, Schain, & Pause, ; Woodruff, Martin, & Bilyk, ), the pain empathy effects were operationally defined as the difference scores of mu suppression between painful and nonpainful conditions. The degree of freedom of the F ratio was corrected according to the Greenhouse‐Geisser method when sphericity hypothesis was violated.…”

Somatosensory mu activity reflects imagined pain intensity of others

“…EEG was recorded from 16 Ag/AgCl sintered active electrodes (positions Fp1, Fp2, F3, Fz, F4, C3, Cz, C4, P3, Pz, P4, O1, Oz, and O2 of the 10/10 system and earlobes), embedded in a stretch Lycra cap (actiCAP, 32-channel standard 2 layout, Brain Products GmbH, Germany). In accordance with previous studies, electrodes C3, Cz, and C4 were used to measure mu activity, while O1, Oz, and O2 served as a control for alpha activity (e.g., Cheng et al, 2008;Hoenen, Schain, & Pause, 2013;Oberman, Pineda, & Ramachandran, 2006;Perry, Troje, & Bentin, 2010). The remaining electrodes were used to correct eye movement artifacts.…”