Response inhibition to emotional faces is modulated by functional hemispheric asymmetries linked to handedness

Effective response inhibition requires efficient bottom-up perceptual processing and effective top-down inhibitory control. To investigate the role of hemispheric asymmetries in these processes, 49 right- and 50 left-handers completed a tachistoscopic Go/Nogo task with positive and negative emotional faces while ERPs were recorded. Frontal resting state EEG asymmetry was assessed as a marker of individual differences in prefrontal inhibitory networks. Results supported a dependency of inhibitory processing on early lateralized processes. As expected, right-handers showed a stronger N170 over the right hemisphere, and better response inhibition when faces were projected to the right hemisphere. Left-handers showed a stronger N170 over the left hemisphere, and no behavioural asymmetry. Asymmetries in response inhibition were also valence-dependent, with better inhibition of responses to negative faces when projected to the right, and better inhibition of responses to positive faces when projected to the left hemisphere. Frontal asymmetry was not related to handedness, but did modulate response inhibition depending on valence. Consistent with the asymmetric inhibition model (Grimshaw & Carmel, 2014), greater right frontal activity was associated with better response inhibition to positive than to negative faces; subjects with greater left frontal activity showed an opposite trend. These findings highlight the interplay between bottom-up and top-down processes in explaining hemispheric asymmetries in response inhibition.