Figure 1.

Visualization of hypothesized effects of acute stress on learning and extinction of pain-related fear. Postulated effects depend on the timing of acute stress in relation to acquisition and/or extinction. (A) Acute stress just before or during acquisition may facilitate the formation and/or consolidation of pain-related fear, reflected by greater retrieval of pain-related fear. (B) Acute stress just before or during extinction learning may improve consolidation of the extinction memory trace, possibly resulting in enhanced retrieval of the extinction memory and hence reduced reinstatement or renewal. (C) Post-extinction stress occurring just prior to or during extinction retrieval may impair the retrieval of the extinction memory and result in enhanced reinstatement or renewal effects. Note that chronic stress or affective comorbidity may differentially affect these processes involving central and peripheral mechanisms of the inter-connected stress and pain systems (not shown here, see text).