Sex differences in visual working memory processing dynamics

The influence of sex on visuospatial working memory processing has been repeatedly studied, suggesting a significant male advantage. However, sex-related dynamic adaptations of brain connectivity during the time course of working memory processing remain elusive. We analyzed the electroencephalographic functional connectivity across different frequency bands using phase-locking synchronization to evaluate the effect of sex during the performance of a modified version of the Sternberg task, across different stages of working memory (WM) processing namely: encoding, maintenance, and retrieval. Forty-five university students (23 female, 22 male) performed the task using memory sets of five uppercase letters, followed by a single lowercase letter serving as the probe. Behavioral results showed slower reaction times for females, who exhibited higher connectivity indices in the theta frequency range during maintenance, particularly involving the left frontal and right posterior temporal areas. In contrast, males showed higher fronto-parietal connectivity in the alpha band during the maintenance and retrieval WM stages, and in the beta band during retrieval. The results suggest a significant effect of sex, not only affecting the behavioral response but also imposing a distinct brain functional dynamic, which likely underlies different cognitive processing strategies.