Olfactory bulb astrocytes link social transmission of stress to cognitive adaptation in male mice.

Emotions and behavior can be affected by social chemosignals from conspecifics. For instance, olfactory signals from stressed individuals induce stress-like physiological and synaptic changes in naïve partners. Direct stress also alters cognition, but the impact of socially transmitted stress on memory processes is currently unknown. Here we show that exposure to chemosignals produced by stressed individuals is sufficient to impair memory retrieval in unstressed male mice. This requires astrocyte control of information in the olfactory bulb mediated by mitochondria-associated CB1 receptors (mtCB1). Targeted genetic manipulations, in vivo Ca 2+ imaging and behavioral analyses reveal that mtCB1-dependent control of mitochondrial Ca 2+ dynamics is necessary to process olfactory information from stressed partners and to define their cognitive consequences. Thus, olfactory bulb astrocytes provide a link between social odors and their behavioral meaning.