Spatial object recognition memory formation under acute stress.

Stress is known to have a critical impact on memory processes. In the present work, we focus on the effects of an acute stress event closely associated to an unrelated learning task. Here we show that acute stress (elevated platform session, EP) experienced one hour after a weak spatial object recognition training (SOR), which only induces a short-term memory (STM), promoted the formation of SOR-long term memory (SOR-LTM) in rats. The effect induced by stress was dependent on the activation of glucocorticoid- and mineralocorticoid-receptors, brain-derived neurotrophic factor (BDNF) and protein synthesis in the dorsal hippocampus. In contrast, EP after a strong SOR impaired SOR-LTM probably by interfering with the use of necessary resources. Moreover, we show that the EP session before training induced anterograde interference, which it was not reversed by a subsequent exposure to an open field. Our findings provide novel insights into the impact of stress on LTM formation in rodents and they are discussed under the behavioral analogue of the synaptic tagging and capture hypothesis. This article is protected by copyright. All rights reserved.