Electrocortical and Physiological Correlates of Memory and Attention During the Anticipation of Avoidable and Inevitable Threats.

When confronted with danger, humans display a range of defensive behaviors, such as freezing and active avoidance. Prior research has identified a distinct physiological response pattern to avoidable threats, characterized by heart rate bradycardia, reduced visual exploration, and suppressed visual alpha activity (8-13 Hz), all of which are associated with faster flight responses. While this pattern indicates an adaptive state of attentive immobility, it is largely unclear how this state influences the encoding of explicit threat-related memories. Clarifying these mechanisms seems important to understand the processes contributing to the formation of pathological fear memories. To address this question, we recorded parieto-occipital alpha activity, eye movements, and autonomic responses in 60 participants during anticipation of either an avoidable threat, an inevitable threat, or no threat, while viewing images of various facial identities. In a subsequent memory task, participants were asked to recognize previously seen faces among novel ones. Results showed enhanced suppression of alpha activity during avoidable threats, accompanied by heart rate bradycardia, centralized gaze, and increased sympathetic arousal. However, these responses were not linked to memory encoding. Instead, memory effects were associated with reduced pupillary responses, heightened visual exploration, and decreased alpha activity, particularly in occipitotemporal regions. Together, these findings suggest that when individuals face avoidable threats, they enter a state of attentive immobility that enhances perceptual processing and prepares them for action but does not extend to improved memory encoding.