Measuring competing motivations: Motivational conflict evokes rapid shifts in asymmetrical frontal alpha power and LPP amplitudes.

Motivational conflict occurs when an individual faces a situation involving competing drives to approach or avoid. Past work using ERPs and resting frontal alpha asymmetry has demonstrated that avoidance motivation and approach-avoid conflict evoke greater relative right frontal cortical activity. However, although they show similar findings, these separate literatures have not been connected. The current study attempted to fill this gap by measuring lateral differences in time domain ERPs and evoked time-frequency alpha (8-12 Hz) power during motivated movements. Participants (N = 71) completed a novel mobile tablet-based version of the approach-avoidance task, requiring ecologically relevant elbow flexion and extension movements to elicit motivational conflict. Participants were asked to make motivationally consistent or inconsistent motor movements while viewing images of disgusting or neutral stimuli. Differences in the late positive potential (LPP) amplitude over lateral frontal sites indicate that motivationally inconsistent (pull) movements toward disgust images activated more motivated attentional processing over the right hemisphere than motivationally consistent (push) movements, compared to other experimental conditions. Complimentary time-frequency analysis suggests that low-frequency alpha power is suppressed over the left lateral frontal cortex when pulling disgusting images compared to pushing disgusting images and pulling neutral images. These results demonstrate that motivational conflict evokes simultaneous time domain and frequency domain changes after motivated movements.