OXYGEN AND COGNITIVE PERFORMANCE - THE TEMPORAL RELATIONSHIP BETWEEN HYPEROXIA AND ENHANCED MEMORY

Oxygen administration coinciding with word presentation enhances word recall in humans, suggesting that elevated levels of circulating blood oxygen may be available to neural memory consolidation processes. Thi s double-blind experiment examined the relationship between blood oxyg en levels and cognitive performance when oxygen was inspired for 2 min at different times relative to a simple word recall task, forward dig it span and backward digit span. Transient hyperoxia, measured by haem oglobin-bound oxygen, was evident following oxygen inspiration. Neithe r forward nor backward digit span was affected by oxygen administratio n. Word recall (12 min following word presentation) was enhanced when oxygen was administered 5 min prior to, immediately before or immediat ely following word presentation; but not 10 min prior to, 5 min follow ing nor 10 min following, word presentation. These data suggest that o xygen administration can selectively enhance aspects of cognitive perf ormance and support a hypothesis whereby supplemental blood oxygen is sequestered by neural mechanisms involved in memory consolidation.