Effects on memory and activation pattern of the dorsal hippocampus in male mice subjected to witness of social defeat stress at different ages

Stress is a risk factor for the development of neuropsychiatric disorders. Epidemiological studies have identified a strong correlation between stress and mnemonic impairment. Furthermore, the age of the individual, combined with the nature of the stressor event, can dictate the individual`s ability to adapt or not to a stressful situation. The animal model of social defeat stress (SDS) allows for the understanding of the neurobiology of social stress responses. Also, it has been demonstrated that the hippocampus is a highly susceptible area to the effects of SDS. It remains to be determined whether the memory impairment induced by SDS is limited to the aggressed animals or if it could also be observed in animals that witness such confrontations. In this sense, we hypothesized that the use of the object recognition (OR) test is a useful tool to investigate the effects of SDS on short-term memory and hippocampus neuronal activation in mice that witness social defeat stress (WSDS).