Fear bradycardia and activation of the human periaqueductal grey

► Aversive stimuli increase activity and connectivity within amygdala-PAG circuitry. ► These stimuli elicit (parasympathetic) bradycardia and (sympathetic) pupil dilation. ► PAG activity uniquely correlates with bradycardia, not pupil dilation. ► This pattern is mirrored in regions involved in motor inhibition.