Negatively valenced stimuli selectively enhance frontal midline theta during inhibitory control

Frontal midline theta (FMT) is a well-established neural marker of cognitive control, yet the extent to which emotional stimulus characteristics modulate this signal remains unclear. The present study examined whether emotional stimulus valence influences FMT during inhibitory control using a modified Go/No-Go task across two experiments. In Experiment 1, participants completed trials in which action cues were paired with negative or neutral images. Results revealed a significant Emotion × Action interaction, such that FMT power was selectively enhanced for negative relative to neutral stimuli during No-Go trials, with no emotional modulation observed during Go trials. In Experiment 2, positive stimuli were included to distinguish between valence-specific and general emotional salience accounts. Replicating Experiment 1, FMT was significantly greater for negative relative to both neutral and positive stimuli during No-Go trials, whereas neutral and positive conditions did not differ. Secondary analyses of control-related FMT (No-Go minus Go) showed greater FMT for negative relative to positive stimuli, whereas negative and neutral conditions and neutral and positive conditions did not significantly differ. Across both experiments, emotional stimulus valence did not reliably modulate behavioral accuracy or reaction time, indicating a dissociation between neural and behavioral indices of control. Together, these findings suggest that negatively valenced stimuli are associated with selective modulation of FMT during inhibitory control, a pattern more consistent with a valence-specific response than a generalized emotional salience interpretation. The absence of reliable behavioral effects further suggests that increases in FMT may reflect enhanced recruitment of control-related neural systems rather than improved performance.