Abstract
When encountering a potential threat, humans and animals engage in different strategic behaviours, such as orienting and defence, depending on the perceived threat imminence. Orienting has been associated with attentional immobility and heightened 'stimulus intake', while defence is linked to action preparation and 'sensory rejection'. First, we replicated previous findings showing that humans exhibit either heart rate (HR) acceleration or deceleration in response to the same threat-related picture content. Second, we provide direct evidence that orienting, as indexed by increased HR deceleration, leads to enhanced visuocortical processing of threat-related images, as measured by steady-state visual evoked potentials (ssVEPs). Excitation of motor-relevant cortical circuits, assessed by beta-band desynchronization, was reduced in relation to HR deceleration. Conversely, HR acceleration was associated with a reversed pattern: reduced visual processing and increased excitation of cortical motor circuits, as reflected in ssVEP and beta-band modulations. While self-reported measures of state and trait anxiety, along with valence, arousal and dominance ratings, did not account for variations in HR response patterns, shorter self-paced viewing time of looming threat pictures was linked to defensive HR changes, whereas orienting-like HR responses were associated with longer avoidance latencies.