Modeling Emotional Arousal With Turbulence Measured by EEG

Turbulence-like dynamics in brain activity have been proposed as a signature of systems operating near criticality, and may reflect changes in neuronal function associated with emotional states. In this paper, we hypothesize that motor behavior linked to emotional expression modulates turbulence, reflecting a shift towards more streamlined brain dynamics characteristic of emotional motor control. We assessed EEG turbulence in 30 healthy participants in a motor paradigm varying in both task demand and degree of emotionality. Conditions included singing, swaying, responding to a virtual conductor of variable expressivity, having your own body movements mirrored by a virtual agent, and combinations thereof. Results showed an inverse relation of turbulence intensity in the alpha range to both degree of movement and perceived level of task emotionality, which was also true for the high gamma range, but to a lesser extent. When factoring in task demand, the effect of level of emotionality in the alpha range deteriorated. This is physiological evidence for why physical arousal is likely to increase the level of perceived emotional engagement or even be misinterpreted as such. Our findings suggest high gamma activity is a more accurate indicator of emotionality during motor tasks and can be key to differentiating EEG signatures of emotional motor control, which has been shown to be partly autonomous from voluntary motor control.