Stress disrupts response memory retrieval

Summary Stress effects on memory are well-known. Most studies, however, focused on the impact of stress on hippocampus-dependent ‘declarative’ memory processes. Less is known about whether stress influences also striatum-based memory processes, such as stimulus–response (S–R) memory. First evidence from rodent experiments shows that glucocorticoid stress hormones may enhance the consolidation of S–R memories. Whether stress affects also S–R memory retrieval remains largely elusive. Therefore, we tested in the present experiment in humans the effect of stress on the retrieval of S–R memories. Healthy men and women were trained to locate three objects in an S–R version of a virtual eight-arm radial maze. One week later, participants underwent a stressor or a control condition before their memory of the S–R task was tested. Our results showed that participants ( n  = 43) who were exposed to the stressor before retention testing made significantly more errors in this test trial, suggesting that stress impaired S–R memory retrieval. Moreover, high cortisol concentrations were associated with reduced S–R memory. These findings indicate that stress may affect memory retrieval processes in humans beyond hippocampal ‘declarative’ memory.